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Improving folding e-bike designs in SolidWorks by optimizing complex mechanism synthesis

May 25, 2023 By Rachael Pasini Leave a Comment

By Jody Muelaner, Ph.D. CEng MIMechE

BriefBike is an e-bike designed to fold in a single, almost instant motion, just like an umbrella. This is a great case study in mechanism design due to the many constraints that must all be considered to ensure the bike performs correctly when being ridden and folded and when in its folded state. I’ve written before about how the constraint-based sketch tools in SolidWorks can be used to solve some relatively simple mechanism synthesis problems. In this article, I show how these techniques can be extended, using scripting and data filtering, to solve a highly complex mechanism design challenge.

BriefBike was designed to fold as quickly and easily as an umbrella, but the initial design was a bit too wide, and there were issues with the way the height of the seat was adjusted. This work optimized the mechanism to provide a more compact fold with enhanced riding geometry.

In a previous article, I introduced how geometric constraint-based sketching can synthesize mechanisms. This article takes the ideas further, providing a real-world example of optimizing a mechanism with many different constraints. Most notably, it shows that it becomes impossible to formulate a single sketch that can encompass all these constraints to directly solve for the optimum solution.

The method, therefore, only uses the geometric constraint sketch to solve the mechanism for a given parameter set. This can be repeated many times for different combinations of input parameters, recording output parameters for each configuration. All the results can then be listed in a spreadsheet, filtered to remove configurations that don’t meet essential criteria, and sorted to find the optimum design. Using a spreadsheet at this stage also allows metrics to be calculated to combine parameters, even potentially creating a single objective function that can be used to rank designs using a single metric.

Using macros to solve large numbers of configurations

In practice, updating parameters in the sketch and recording driven parameters in a spreadsheet becomes time consuming and error prone as soon as there are more than a few parameters to update. For example, with seven parameters (or factors) and just three parameter values (or factor levels), there are 2,187 configurations. Even if you could update the parameters in the sketch and record the values in Excel for one configuration in just one minute, it would still take a week of tedious work. Using Excel-driven configurations in SolidWorks may seem like the obvious solution, but in practice, this doesn’t work well for a very large number of configurations. The solution is the use the SolidWorks API to open the file, read in the parameter set, rebuild the model, and store the results. We created an application to do this, which uses three simple text files for inputs and outputs:

Inputs.txt: This file is created by the user to define the problem to be solved. It has three lines:
- The file name of the SolidWorks part to open and interact with
- A comma-separated list of the driving parameters to be updated by the script
- A comma-separated list of the driven parameters to be recorded by the script
Parameters.txt: This file is also created by the user. Each line represents a different configuration as a comma-separated list of values, with each value corresponding to one of the driving parameters listed on the second line in inputs.txt.
Outputs.txt: This file is created by the script. It has a similar structure to parameters.txt, with each line also representing a different configuration as a comma-separated list of values for each parameter. In this case, it is the driven parameters listed on the third line of inputs.txt that are listed.

The mechanism design process involves first defining the problem in SolidWorks, generating configurations in Power Query, solving all configurations using a SolidWorks API script (we’re using an in-house code DimWorker.exe), and then identifying the optimum solution by analyzing the results in Excel. Experimentation and iteration are likely to occur at multiple points within this process.

Understanding the constraints

A demonstrator had already been created, which proved the bike could be unfolded in less than half a second. However, it was still a bit too wide when folded, and optimizing the mechanism to further reduce the folded width without impacting the important ride characteristics was proving challenging. The large number of constraints that needed to be simultaneously satisfied meant that a direct solution to find the optimum mechanism was not possible. This method of using a script to generate multiple solutions was therefore created.

The key criteria for BriefBike can be summarized as follows:

Folds and unfolds in a single effortless motion into a roller case format
- Less than 500 mm wide, able to roll behind a person through doors and crowds, and fit second-stage luggage fold
- Approximately 1,100 mm in height, providing correct grip height for rolling along
- Less than 150 mm thick to conveniently store flat against a wall and be held tight against the body when in confined spaces
- Transmission angles must be greater than 30° so the linkage does not bind
Second stage fold that reduces the height to under 700 mm to be within the standard luggage size for trains internationally (700 x 500 x 300 mm)
Stable two-wheeled trailing-link design when in roller case format, explained below
Riding geometry must be comparable with a conventional bicycle. The most important parameters are the head angle, trail, wheelbase, position of the bottom bracket between the wheels, and effective stem length. These parameters are illustrated where the parametric sketches are defined later in this article.
The frame must be structurally efficient. Dimensions measured on the sketch can be used as inputs to free body diagram calculations for truss joint forces at the Excel stage.
Parts must not clash with each other during the folding process, and various clearance dimensions with the defining sketches reflect this requirement.

What I mean by a stable two-wheeled trailing-link roller case format can be easily understood by considering the two different types of roller cases commonly available. First, there is the four-wheeled variety that you push in front of you. The four wheels form a reasonably stable base and roll along fine on smooth surfaces. However, if the surface is rough or you want to break into a run, the small base and high center of gravity mean they tip over easily. And then there are the two-wheeled roller cases that drag behind you. In this case, the base forms a stable tripod between the wheels and your hand. Even if you suddenly accelerate or run the case straight into a curb, the wheels lift off the ground and land again in a stable position, and there is virtually no tendency to tip over. While many folding bikes include wheels that allow them to be moved like a four-wheeled case, BriefBike is designed to be pulled along like a two-wheeled case.

BriefBike was designed to have a wide two-wheeled base that can be easily dragged behind you. This is quite unlike current folding bikes, which are more like the much less stable four-wheeled roller cases. Even when they are pushed on two wheels, they perform in the same unstable way because they are narrow and pushed in front of you. Only a flat, wide wheelbase dragged behind you provides stability required to move at speed over rough surfaces when the propulsive force provided by your hand is applied at a height way above the wheels.

The driving parameters define the mechanism using two sketches. First, a sketch defines the ride geometry using ten parameters, including the wheelbase, trail, head angle, reach, and crank length. The head angle is driven by a linear dimension, as inputting angles using the API proved more difficult.

The RideGeom sketch defined the important parameters affecting the handling of the bike. This was then used as a reference for the LinkSynth sketch, which solves for the linkages that enable the bike to fold.

The second sketch is the one that actually solves the mechanism synthesis problem. It achieves this by drawing the mechanism in the folded and unfolded positions, defining certain key parameters but allowing the constraint-based solver to determine link lengths and joint positions to achieve the required motion. A great deal of trial-and-error experimentation was required to find a robust way of constraining this sketch with dimensions that allowed many different configurations to be tested without the sketch failing to solve.

The LinkSynth sketch is where all of the mechanism synthesis actually happens. The main folding mechanism is a four-bar linkage; the ground link is not shown. The three remaining links are shown in the riding position with a thick dotted line and in the folded position as a thick solid line. Other construction, steering, and envelope geometry are shown with a thin line. The wheels are only shown in the folded position, and the front and rear axles of the frame are mated to the RideGeom sketch, which is hidden in this view. The fixed ground link is represented by having the joints where the links connect to it coincidentally. The links are set to be of equal lengths in the two positions, and angles are also forced to be equal by triangulating and setting equal length constraints on the diagonals.

The large number of parameters in the model means that even when using automation, parameter levels must be selected sparingly. If the 16 driving parameters were each given five values, there would be 150 billion configurations. With each configuration taking about 0.1 seconds to rebuild and store the parameters, this would take 480 years!

In practice, with larger parameter sets, memory issues with storing all the outputs mean the time per configuration can increase dramatically. Even much smaller parameter sets can therefore become unfeasible. So, while an automated optimization allows far greater experimentation than you could hope to achieve manually, you still can’t just get the computer to try every possible configuration. Therefore, it’s a good idea to start by manually exploring the parameters to determine which are most sensitive and then use the optimization code to explore combinations of potentially interesting parameter values. This design was explored through six iterations of optimization, with between 1,000 and 40,000 configurations in each.

Setting up Excel to generate configurations and filter results

Once you have selected a set of parameters to explore, you must generate a table with all the combinations. This is known as a full factorial set in the design of experiments. The easiest way to do this in Excel is by using Power Query, another Microsoft tool bundled with Excel. The process involves connecting tables in an Excel workbook to queries in Power Query. This is a bit too involved to explain fully here, but it’s not difficult and is explained well in this YouTube video. Once Excel has generated the table of configurations, this can be copied and pasted into Parameters.txt.

The 18 output-driven parameters were copied into an Excel table with the 15 input-driving parameters. An additional 25 columns were added to calculate other quantities from the parameter values; these included clearances between components and forces calculated at joints. All configurations were then filtered to ensure sufficient clearances and identify the most desirable characteristics, such as longer wheelbase, steeper head angle, more direct transmission angles, lower joint forces, and a more compact folded package. These selection criteria were drawn from driving and driven parameters and values calculated in Excel.

Results

This mechanism optimization work resulted in a bike with a longer wheelbase, steeper head angle, and longer trail, all resulting in a more stable ride. At the same time, the frame is more structurally efficient, and it folds into a much more compact package. You can find out more about BriefBike at http://www.betterbicycles.org.

Designed by engineers with nature’s help

March 29, 2019 By Leslie Langnau Leave a Comment

Engineers are increasingly turning to the already perfected designs found in nature to create lightweight and optimized products. And one software program—also inspired by nature– optimizes the CAD model for the job at hand

Jean Thilmany, Senior Editor

Want an example of efficient, environmentally friendly design? Look to nature.

When engineers take a biomimetic approach to their projects, they’re taking inspiration from how plants and animals, even the microbes around us, work. Nature has had eons to perfect its systems and shapes. Engineers haven’t. But they can crib from nature’s design methods and at least one form of CAD and analysis technology—itself based on biomimicry—can help.

Advances in additive manufacturing techniques mean the unusual geometries found in nature can be attempted and feasibly manufactured today.

For a modern-day example of biomimicry (that is, engineers drawing upon biology for their designs), look at the 500 Series Shinkasen Japanese bullet trains, which can reach speeds up to 200 miles per hour. This train was developed in 1992 to test technologies for future bullet trains. For the 500, designers wanted a fast train that ran quieter than earlier models.

Modeled after the kingfisher, the Shinkansen Bullet Train has a streamlined forefront and structural adaptations to significantly reduce noise.

Designer Eiji Nakatsu modeled the train’s nose after the beak of the kingfisher bird, which dives from air to water with very little splash thanks to its aerodynamic beak. The 500 is not only less noisy than earlier versions of the bullet train, it uses 15% less electricity and travels 10% faster, he says.

A few years ago, researchers in the University of California, Berkeley, Biomimetic Millisystems Lab created an adhesive based on the method geckos use to climb walls or hang from a tree branch from just one toe. They created the self-cleaning adhesive made from the long, slender polypropylene fibers that mimic the millions of hair-like structures called setae on the bottom of a gecko’s toes.

The adhesion is based on the geometry of the fibers: sliding the tape against a surface uncurls the fibers to engage the adhesive while sliding the tape in the opposite direction causes it to unstick, says Ronald Fearing, an electrical engineering professor at the school who led the research.

Because engineers could optimize the geometry of the polypropylene fibers using engineering analysis software, the adhesive can be made much stronger and stickier than a gecko’s feet. Also, the gecko adhesive, unlike conventional adhesive tapes, does not feel sticky to the touch, Fearing says.

Making things lighter, stronger and faster has long been the goal in engineering and biomimetics is one tool that can help. Automotive and aircraft companies—to name just a few—want to decrease the weight of their products as much as possible so they burn less fuel and are easier to handle.

Some of them—Airbus, Boeing, and Volvo among them—are using a topology optimization tool to cut excess material and weight. The tool is itself based on algorithms derived from a natural, biological process.

From the body to the aircraft
Engineers have been using the OptiStruct topology optimization program from Altair Engineering to optimize their CAD models for weight and strength. The program does this in the same way bones grow to be as light and strong as possible, says Janine Benyus. She’s co-founder of the Biomimicry Institute, of Missoula, Mont., which states its mission is to promote the transfer of ideas, designs, and strategies from biology to sustainable human systems design.

The OptiStruct program, developed by Jeff Brennan, is based on the way human bones grow. As a biomedical graduate student at the University of Michigan, Brennan investigated the theory that bone growth responds directly to external stimuli, he says.

He and his fellow researchers created a mathematical model to represent bone growth in the human body, theorizing the model could help point medical researchers toward ways to induce bone growth to treat conditions like osteoporosis. They found that bones grow in response to stress into an optimal structure through trial and error, says Brennan, now chief marketing officer at Altair.

And bones, of course, are not stiff and heavy. Rather, they’re porous, lightweight, but very strong. Many engineered structures could be designed in that same way, he says. Brennan applied the mathematical growth patterns seen in bone to static structures to bring to them that same type of lightweight, strong flexibility.

Brennan’s model is now the basis of the Altair topology optimization program. Engineers use topology optimization to discover the best way to distribute material throughout a structure, given their goals for that structure as well as their set of constraints.

The topology optimization software OptiStruct is based on human bone growth patterns. It’s now included in HyperWorks from Altair. Depicted is the way the software can filter and handle thousands of curves.

Now companies in many different industries use the Altair software to analyze and optimize structures for strength, durability and noise, vibration and harshness (NVH) characteristics and to help improve on existing designs, Brennan says.

For instance, the software was instrumental in helping Airbus reduce the materials used for certain wing and airplane rib assemblies by up to 40 percent, Benyus says.
“It’s pure biomimicry in the sense that by studying bones and then mathematically describing what it is they do to make themselves lighter, we’ve been able to save all of this material, but you wouldn’t look at that plane and say, ‘That’s biomimicry,’” she says. “But there’s biomimicry inside, and I really think that these are some of the most powerful things, these algorithms.”

The software offers engineers a different way of thinking about the design process. They can use topology optimization to specify constraints and them simulate potential designs before they’ve created their initial CAD model, Brennan says. They can choose the best of the potential designs returned to them and then further optimize them and adjust to their own needs, he adds.

The designs suggested by the tool may require some additional redesign or tweaking so as to be manufactured using traditional processes. The tool may suggest unorthodox shapes that just can’t be made with the help of a CNC machine or with an extruder, for example.

Though 3D printing is changing that…
As additive manufacturing continues to evolve it gives engineering companies the capability to manufacture nontraditional designs. Because 3D printers build up materials layer after layer they can print objects with any type of geometry. With 3D printing, for instance, designs can be created in intricate or swirling shapes. It also means patient aids like a prosthetic limb or dental implant can be printed exactly to the wearer’s unique shape and specifications.

A design practice and Airbus researchers teamed to design a partition for its A320 series. The partition is 3D printed for lightness and its shape is based on the structure of slime mold, for strength.

And the printers can now produce objects in a variety of materials. The introduction of engineering-grade metals to 3D printing, along with the already-existing array of engineering-grade thermoplastics, means manufacturers can build parts that are strong, yet lightweight, and that can be used directly in the final product.

Look, up in the air (the design of slime)

Airbus continues in its efforts to reduce the weight of the aircraft by using biomimicry and additive manufacturing.

Bastian Schäfer, an Airbus engineer, believes the capability to 3-D print airplane parts that range in size up to and including the plane’s very skeleton structure will revolutionize air travel. These lightweight additively produced parts will make planes that weigh much less than today’s models. A lighter plane uses less fuel and reduces the amount of greenhouse gases it emits. Planes with a smaller carbon footprint could be bigger and roomier, with improvements like larger and moldable seats, Schäfer said.

For him, the move to a 3-D-printed airliner begins with a printed partition his group unveiled two years ago and continues to perfect.

Schäfer is project manager on what his group calls the Bionic Partition Project. The project itself is under the purview of the Airbus Emerging Technologies and Concepts Group, led by Peter Sander.

Working under Schäfer, the group has created a 3-D printed partition to separate the seating area on the A320 from the galley. The partition weighs 45% less than the 7-feet-tall partitions now used on that model. It’s also substantially stronger, as the team replaced the component’s solid aluminum alloy parts with a number of slender, 3-D-printed metal pieces that connect to form a lattice of the same shape and size as the existing partition. The lattice is then covered in a thin material.

Partitions of this nature are large, weighty, and can be somewhat of a design challenge, Schäfer said. It needs to include a cutout wide and tall enough for a hospital stretcher to pass through and to be strong enough to anchor the two seats that fold down from the frame, which flight attendants sit in for takeoff and landing. And it must withstand impacts of up to 16 g-force. Oh, and it also must be less than 1-inch thick (to save space) and attach to the plane in only four places to decrease the weight of connecting hardware and to make for easy changeout.

With all that in mind, the team turned to nature. The partition’s internal, 3-D-printed structure mimics that of human bones, which, though light, have a high strength-to-weight ratio as they are dense at their stress points. Schäfer’s team designed a lattice structure comprised of metal pieces that are printed individually and then fit together to form the partition.

The Living, an Autodesk-owned design and prototyping studio in New York, also played a part in the project by creating the biological algorithm that would allow for the mimicking of human bones.

“Our algorithm was based on the growth of an organism called slime mold,” says David Benjamin, head of the group.

The mold grows and stretches its form to connect a set of points—or locations of food—with the minimum number of lines. It also has built-in redundancy; each point is connected with at least two lines so if one fails, the point is still connected to the network, or slime body, he says.

“The mold spores are efficient because they use the least amount of material to connect the dots. And they are redundant because when one of the paths is broken, the network can route around the problem and stay connected,” he said. “Although the size and material of the partition is different than that of slime mold, the logic is similar. And in our application, this approach worked very well.”

Schäfer has plans to further improve upon the partition’s existing design and build. He’d like to cut out a step in the manufacturing process by printing larger pieces of the structure at once, rather than printing the individual parts that are then fit together. Printer size now limits this capability.

The partition isn’t in production, but that will probably change within five years as Airbus furthers its move toward lighter planes, Schäfer says.

While no slime mold was injured in the making of the Airbus partition, the lowly organism will soon be helping the planes use less fuel—and emit fewer greenhouse gases—as they fly through the skies.

You may not want to thank the slime mold in person, but the engineers who use it—and well as many other natural designs—for inspiration—may just to do it for you.

Altair Engineering
www.altair.com

CAD and Analysis: Integration and Beyond

December 18, 2018 By Leslie Langnau Leave a Comment

CAD and analysis programs need to work together. Regardless of how the geometry gets to the analysis program, the important thing is it gets there easily and can be quickly analyzed. That smooth transfer and analysis are how companies are cutting product lifecycle time and increasing profits.

Jean Thilmany, Senior Editor

You’ve created your CAD design, but you’re not done. You need to analyze the geometry to ensure air or fluid will flow through it correctly, that it can withstand a certain amount of pressure, that it’s structurally solid, or that it meets a host of other specifications.

The important thing is that the model needs to be analyzed within the analysis software.

CAD and analysis software work together much better than in the past, when CAD models had to be exported, then imported into the analysis software that then required engineers make even more changes before they could be read.

Today, CAD and analysis integration is key. But it’s not everything. The way modeling and analysis work together depends on the type of work you do and the physical forces you need to analyze. Sometimes geometry is imported directly from the CAD package. Sometimes geometry is created within the analysis software itself.

Because these needs vary, some products–like Comsol multiphysics analysis software–contain two engines for creating and managing geometry. Once the geometry exists within Comsol, the software can solve for more than one physical effect that acts on the geometry at the same time.
Comsol’s CAD import module–as the name implies–directly imports CAD geometry. Or, users can create their own geometry directly within the multiphysics software.

Regardless of how they get CAD into the analysis system, engineers and analysts will need to select the physical phenomena they want to apply. For this, they’ll need to mesh their designs. The mesh, which looks like a net over the model, creates nodes that the analysis software applies mathematical formulas to and studies.

“Some of our users analyze designs that are generated within a design department. That could be a product that’s close to being released,” says Lorant Olasz, Comsol’s technical product manager working with CAD. “Those geometry files are not drawn for simulation, so they come with some challenges for analysis.”

In those cases, the existing model will need to be meshed and, often, simplified, for analysis.

“But, in the end, we provide tools that allow you to work as if the geometry had been drawn directly within Comsol,” he adds. “You shouldn’t feel like, ‘I’m importing something and it’s not going to work!’ It just works,” Olasz says.

Electrical engineers can also analyze their printed circuit board designs in Comsol. The recently upgraded software now has the tools to generate geometric objects from the 2D layouts of ECAD files, group them into easy-to-use selections for simulation setup, and automatically take care of the geometric complexity inherent to ECAD formats before meshing.

All multiphysics analysis tools offered by Comsol can be run on the imported CAD model. Engineers need not worry they won’t be able to solve for, say, both structural and fluid-flow within the same, imported model, Olasz adds.

Both CAD import and the CAD design kernel allow users to import and then repair geometries, “and if you’re using the design kernel you have a few extra g operations like fillets or the option to thicken the surface of a solid,” he said.

The CAD Import Module supports the import of a variety of different file formats including the Parasolid and ACIS formats, and standard formats like STEP and IGES. Users import their files by saving them in any of these formats. The import module also allows users to import the native file formats of a number of CAD systems, such as Inventor, Creo Parametric, and SolidWorks. The optional file import for Catia V5 provides support for importing the native file format for this system.

Sometimes, for various reasons, engineers will choose to make preliminary, or even final designs directly within the analysis tool, he says.

At the beginning of the design process, for instance, engineers sometimes quickly create a model directly within their analysis software, which they use to test and analyze the feasibility of several ideas and variations. This makes it easy to find the geometry needed to meet fluid-flow and other specifications before designers commit to modeling the part in-depth within a CAD package, Olasz says.

“If you don’t need all the details, sometimes it’s faster to quickly draw something in your analysis package rather than try to simplify a complex assembly and take out the components not needed before you analyze it,” he says. “It really depends on the workflow you’re in.”

Designing directly within the analysis tool is often done if the piece will never be created in real life. The geometry still needs to be analyzed for other purposes.

A model eye

Take the case of the human eye. One company recently created an exact digital replica. They don’t intend to actually create a human eye. Though researchers are experimenting with 3D printed organs, they haven’t yet moved to experimenting with the eye. Instead, the model is used to study the human eye with the intent to change it with laser treatment. Or, as many middle-aged humans like to think, to perfect it.

Engineers at the company, Kejako, in Switzerland, created and imported 3D geometries pertaining to the human eye. Once the geometry was in Comsol software, they worked on that model some more. They were studying how laser treatment might work for aging eyes.

Engineers at Kejako in Switzerland created and imported 3D geometries pertaining to the human eye to study how laser treatments might work for aging eyes.

Let’s face it, almost everyone will need reading glasses or bifocals or specialized contact lenses as they age thanks to presbyopia. There is an operation that can decrease dependency on reading glasses and like, but as with all surgeries, it’s invasive and comes with risk.

Presbyopia is very common in middle age and older adults as it’s due the loss of elasticity in the lens of the eye that comes with aging, according to the National Eye Institute, part of the National Institute of Health. In 2015, 1.8 billion people around with world had presbyopia, according to researchers publishing in the journal Ophthalmology in 2015.

Presbyopia is a common eye condition due to the loss of elasticity in the lens of the eye that comes with aging. In 2015, 1.8 billion people around with world had presbyopia, according to researchers publishing in the journal Ophthalmology in 2015. Kejako hopes to develop a procedure that helps people with this condition.

Younger people who still have soft and flexible lenses within their eyes, can adjust their eyes easily to focus on close and distant objects. That’s why they don’t have to hold their restaurant menus at arm’s length to read them.

David Enfrun cites research that finds presbyopia will affect 2.3 billion people across the globe in 2020. He theorizes, probably correctly, that quite a few of them will resist wearing reading glasses or bifocals because they think the look will immediately age them, he says.

Enfrun is Kejako’s chief executive officer. His company is at work on a method to fend off the need for reading glasses and do away with the need for the invasive surgery that can correct presbyopia.

To that end, two years ago engineers at the company built a 3D model of the human eye that they use to determine how the eye changes over time.

“We built a full-eye multiphysics 3D model with consideration for mechanics, fluidics and optics,” Enfrun said. “We have imbedded in our multiphysics model everything necessary to simulate visual accommodation, explain the root causes of the occurrence of presbyopia, and to test any potential solution,” Enfrun says.

Engineers at Kejako built a full-eye multiphysics 3D model with consideration for mechanics, fluidics and optics. With the help of the model, researchers and engineers were able to brainstorm a list of potential solutions to presbyopia and model the way those solutions would affect the human eye.

Computational modeling enables the company to validate their concept before it goes to clinical trial, he adds.

With the help of the model, researchers and engineers were able to brainstorm a list of potential solutions to presbyopia and model the way those solutions would affect the human eye, Enfrun says.

The company is now moving forward with a concept of what it calls phakorestoration, which is a series of laser eye surgeries. They begin when a patient first develops presbyopia and continues until the patient develops cataracts. Kejako plans to soon bring phakorestoration to market.

To create the accurate 3D model of the eye that led to the creation of phakorestoration, several physics phenomena were considered as were the eye’s material properties, said Aurlien Maurer, research and development engineer at Kejako, who lead the project. Always acting within the eye are many different types of physics, such as the fluidics of the aqueous human; optical behavior of the lens and cornea material; and refractive index, which involves modeling the muscle ligaments as they deform the lens.

“We wanted to model the entire eye and adapt its properties to look at different outcomes,” Maurer says.

The Kejako researchers used geometries from statistical measurements and optical coherence tomography imaging techniques, which they then translated into a 3D geometry. Then they imported that information into Comsol. When the geometry was within the analysis software they modeled the mechanical elements of the eye, including the complex muscle ligaments that pull the lens into shape, and the viscoelastic properties of the vitreous fluid that fill the eye.

Once the Kejako tool is released, clinicians will be able to use the standard OCT imaging to image a patient’s eye. They’ll then send that information to Kejako, where a team can create a personalized 3D parametric full-eye model of the individual’s eye. The model is then further optimized and customized and a phakorestoraction procedure particular to the patient is created.

The procedure tells doctors how to perform the laser surgery on that particular eye and can detail when it will likely need to be done next, after the patient’s lens changes and needs further accommodation.

Comsol
www.comsol.com

MSC Apex Harris Hawk accelerates structural analysis for aerospace composites

June 26, 2018 By Leslie Langnau Leave a Comment

Bruce Jenkins | Ora Research

MSC Apex Harris Hawk is the eighth release of MSC Software’s revolutionary new CAE platform aimed at making sophisticated, full-powered structural modeling and analysis capabilities easily, intuitively and safely usable by engineers and designers without specialized CAE training and expertise. This newest release targets the need for accelerated structural analysis in aerospace engineering and manufacturing. For background, see our MSC Apex Grizzly: Structural analysis for massive assemblies and MSC Software democratizes vibrational analysis with MSC Apex Fossa, both published in this blog.

Aerospace vehicles are some of the most complex structures to design because of the high levels of physics and mathematics involved, MSC notes. “CAE has been a key driver for reducing cost and accelerating innovation,” the company observes, “but current processes still suffer workflow inefficiencies, and results often come too late in the design cycle—especially when designing composite structures.”

“Unique composite modeling and simulation experience that closely mimics the steps of the manufacturing process”

MSC Apex Harris Hawk delivers what the company describes as a “unique composite modeling and simulation experience that closely mimics the steps of the manufacturing process.” Instead of using finite element abstractions, MSC Apex lets engineers manipulate physical representations such as fabric, layups, plies, panels and zones. Within a few hours, the company reports, MSC Apex users can become efficient with composite modeling and on-the-fly failure calculation.

structural modeling and analysis — MSC Apex Harris Hawk model of a composite-layup airframe structure.

“MSC Apex gives EcoFlight the tools it needs to fulfill many of our aerospace and motorsport engineering analysis requirements,” says John Wighton, Director at EcoFlight, an Aspen, CO-based organization that uses small aircraft to educate and advocate for the protection of remaining wild lands and wildlife habitat. “The composite functionality in Apex Harris Hawk embeds methodology and capability, which greatly improved process efficiency. We couple the advanced composites capabilities of MSC Apex with MSC Nastran to give consulting clients a flexible and fast capability at a cost-effective price.”

Key new features

Modeling productivity—This release introduces a new geometry tool for surface extensions to eliminate manual rework and to allow engineers to automate model preparation tasks. Generative tie connections for assembly creation now takes minutes instead of hours, MSC says. Users can now create large assemblies of parts using mesh-dependent connections while preserving the product structure. MSC Apex Harris Hawk also features a high-performing hex meshing tool to help users mesh complex solid geometries.

Complete structural analysis—MSC Apex Harris Hawk expands its structural analysis capabilities with support for multi-events static analysis. Users can now manage multiple load cases. It also provides the ability to define pre-stiffening in the linear bucking scenario. The brand-new model browser-picking tool better supports result processing for model introspection.

Open and complementary—Beyond modeling productivity and structural analysis completeness, MSC Apex Harris Hawk continues to build on an open and interoperable framework through a full set of Python scripting APIs for conceptual modeling iterations, and interoperability with MSC Nastran-Patran including export of scenarios.

MSC Apex Harris Hawk

EcoFlight

The perfect, unorthodox design

June 15, 2018 By Leslie Langnau Leave a Comment

What if you could create the perfect part unlike anything that exists today? New CAD tools combined with 3D printing can make that happen, makers say.

Jean Thilmany, Senior Editor

No matter what you call the design method, having the computer generate the designs from am engineer’s directions may just be the future. Unorthodox, 3D printed shapes can be found in aerospace now. Soon, such designs will be all around you.

3D printing methods are enabling the development of shapes unproducible by other manufacturing methods. Now, CAD developers are including design tools that take full advantage of the capabilities of 3D printing. These tools are often labeled generative design or topology optimization. They enable engineers to use design software in a new way to best fit design needs.

In April, Autodesk released generative design to subscribers of its Fusion 360 Ultimate product development software. The design concept allows engineers to define design parameters such as material, size, weight, strength, manufacturing methods, and cost constraints–before they begin to design. Then, using artificial-intelligence-based algorithms, the software presents an array of design options that meet the predetermined criteria, says Ravi Akella, director of product management at Autodesk.

“Our effort now is in helping people define the problem they’re trying to solve,” Akella says. “That’s a shift in focus in this industry and makes people have to change the way they have to work.

“The software asks the user preliminary questions. ‘What sorts of materials would you consider for your design? Where does it connect with other things as part of an assembly? What are the loads? What are the pieces of geometry?’” Akella says.

This Elbo chair was designed using Project Dreamcatcher, which was the name Autodesk used for its generative design tool before officially unveiling it this spring.

The software then presents designers and engineers with an array of design options that best meet their requirements. Designers choose the best option. Or, if none of the options meet their needs, they can begin the generative process again, this time offering slightly different inputs.

The computer-generated (“generative”) designs might be unorthodox, new, and unexpected, with geometries that wouldn’t naturally occur to the designer. Yet, no matter how different, if the design is shown to work, it can be created through additive manufacturing,” Akella says.

The method adds value to the present way designers use CAD software, he adds.

“None of these generative questions are asking ‘What is your solution and please start documenting it,” he says. “Without generative design, it’s like engineers were using a piece of paper to explain the problem to themselves. Our job is to get all of that into software.”

He compares generative design with the job of the wine merchant.

By using Autodesk’s generative design and additive manufacturing technologies, engineers at Stanley Black & Decker shaved more than three pounds off this crimping tool attachment, reducing the weight by more than 60%.

“Someone walks into a wine store and wants a Cabernet Sauvignon,” he says. “To get the best version you go in and say ‘It’s summer and this is what’s on my dinner menu’ and you’re trusting the sommelier to present you with a variety or vintage you’ve never heard of.

“Generative expands your solution options, which sometimes aren’t intuitive,” Akella adds. “Users look at their results and think ‘I never would have thought of it. I’m not sure it’s the right answer but I’m going to check it out further.”

By any other name?

Akella takes issue with what he calls “technologies that masquerade as generative design,” which, he says, include topology optimization, lattice optimization, or parametrics.

“Topology optimization assumes you have a solution you’ve thought of and are making a better version of that solution,” he says. “But generative design expects the user to define the problem they’re trying to solve. Then we use cloud computing and other technologies to present them with a set of solutions that solve their problem in a practical, manufacturable way.”

Generative design produces many valid designs instead of an optimized version of an already-modeled part.

“Optimization usually involves removing excess material without any notion of how something is made or used,” he says.

Generative design also takes manufacturability into account, which reduces an engineer’s need to redesign products after manufacturing weighs in, Akella says.

But developers and executives at other makers of CAD technology may take issue with that depiction of their topology optimization features, which can radically change designs and reduce weight and slash costs, they say.

SolidWorks introduced topology optimization capabilities into its recent release of SolidWorks 2018 Simulation Professional and Simulation Premium.

“We expect the computing platform to anticipate your design goals,” said Gian Paolo Bassi, chief executive officer at Dassault Systèmes SolidWorks, when he spoke at SolidWorks World 2018 in January.

“The era of design and validate is about to end. We are entering the era of optimize and manufacture,” Bassi said.

That means designers specify the aspects of the part they absolutely need, including loads, constraints, boundary conditions, and manufacturing methods. The CAD tool then supplies many versions of a near-optimized part, Bassi says.

Topology optimization can be an additive or subtractive algorithm, meaning it can create parts based on user inputs like loads and boundaries or it can subtract from an existing design by essentially chiseling away at the part, says Robbie Hoyler, a SolidWorks elite application engineer for TPM, an engineering services and design provider in Greenville, S.C.

SolidWorks uses the subtractive method. It creates a meshed part based user-defined loads, constraints and boundary conditions. The software cuts out elements that offer few structural or manufacturing benefits. This process is then repeated until the part meets all constraint requirements, Hoyler says.

The optimized CAD design shows engineers the areas of the part that need to stay and the areas where material can be removed, Hoyler says. He cited an example in which SolidWorks topology optimization reduced the weight of an existing part by 50% without removing areas designers had flagged as necessary.

The part can then be saved as a mesh body in the stereolithography (SL) format for 3D printing or can be retraced as a new SolidWorks part.

Another software package, Inspire, also features generative design and topology optimization tools. It allows users to save the enhanced design as a CAD model (skipping the retracing step). The software is from Altair channel partner solidThinking.

The Inspire’s generative feature is easy to learn and is ideal for small and medium-size businesses with little or no simulation experience, says James Dagg, Altair’s chief technology officer for user experience.

Solid Edge, from Siemens PLM Software, of Plano, Texas, also includes a generative design feature that brings topology optimization to the Solid Edge 3D product development toolkit, according to the company. With the feature, designers define a specific material, design space, permissible loads and constraints and a target weight, and the software automatically computes the geometric solution.

The results can be immediately manufactured on 3D printers, or further recreated as a Solid Edge model for traditional manufacturing. Designers can run multiple weight targets, load cases and constraint scenarios simultaneously, according to Siemens PLM.

Refining the real world
Recently, engineers at automaker General Motors began putting Autodesk’s generative tool to the test to cut weight from GM vehicles. Lighter cars use less fuel, emitting less carbon.
Since 2016, the automaker has launched 14 new vehicle models with a total mass reduction of 350 pounds per vehicle, says Ken Kelzer, GM vice president of global vehicle components and subsystems. The 2019 Chevrolet Silverado, for example, reduced mass by up to 450 pounds as compared to earlier model years.

To further lighten the load, as it were, in May the automaker announced an alliance with Autodesk that will use additive manufacturing and Autodesk’s generative tool to develop future cars and trucks, Kelzer says. The pairing of additive and generative capabilities is a natural for the automaker, Kelzer adds.

GM has used additive technologies for more than 30 years to print 3D parts. The automaker has more than 50 rapid prototype machines that have produced more than 250,000 prototype parts over the last decade, Kelzer says.

And the generative capabilities now included in the Autodesk CAD systems put those printers to work in unique ways, he adds. “When we pair the design technology with manufacturing advances such as 3D printing, our approach to vehicle development is fundamentally different; to co-create with the computer in ways we simply couldn’t have imagined before, Kelzer says.

But the design of formerly unimaginable parts doesn’t mean the engineer lacks ingenuity. Rather, those reduced weight, and perhaps rather odd-looking shapes are the whole point of the generative process, which provides thousands of solutions to one engineering problem, Akella says.

He gives the example of a designer who wants to create a chair. Typically, the designer would start with some geographical representation of the chair humans have taken for granted for centuries; that is, four legs, a seat, and a back. But if the designer were to begin by specifying the amount of weight the chair must support, the materials it will be comprised of, and its cost, “the designer will get hundreds or even thousands of options he or she couldn’t have conceived of on their own,” Akella says.

The nature of the creation process also allows for a part with such complex geometries that it can replace multi-part assemblies. And they can be created with 3D printing, he adds.
The process is also being tested in other industries that design with CAD tools.

For instance, architects at Arup, the building and infrastructure design consultancy in the Netherlands, paired topology optimization and additive manufacturing to redesign a steel node for a unique, public lighting and artistic tensegrity structure.

Needle Tower, public art by American sculptor Kenneth Snelson demonstrates the concept of tensegrity. The piece is located outside of the Hirshhorn Museum and Sculpture Garden in Washington, D.C.

Buckminster Fuller coined the term tensegrity to refer to a structure that uses the principle of floating compression, with parts compressed inside a net of continuous tension with cables or tendons delineating the system. Think, of course, of his famous geodesic domes.
Arup designers created their trio of tensegrity structures for a shopping street, the Markstraat, in The Hague. Unveiled in 2013, the “urban chandeliers” integrate street lighting and add an artful element to the area.

Arup architects designed several variations of the node using conventional and optimization techniques. The third figure, on the right, is the final, lightest shape attained through topology optimization.

The urban chandeliers are beautiful. But they weren’t easy to create, says Salomé Galjaard, an Arup senior designer for the project.

Due to the irregular shape of the structures most of the 1,600 nodes that connected the cables to the struts, were different due to the more than one thousand variations in angle and position of the attached cables, Galjaard told attendees at the 2015 Future Visions symposium in Amsterdam.

The Arup architectural firm created this 3D-printed, optimized node for a study of nodes used in its urban chandeliers street-lighting project in The Hague.

“This ‘uniqueness’ inspired us to learn more about additive manufacturing,” she says.
Curious as to what optimization could have done for them on a project like the urban chandeliers, Arup designers conducted a study. Both topology optimization and additive manufacture have been little used in the architectural world, so this seemed like an excellent opportunity.

After performing topology optimization, using the Optistruct software from Altair, they found the node they’d modeled traditionally closely resembled the optimized node. And yet, that optimized design reduced the weight the node from 44 pounds to 11 pounds, a 75% drop, without compromising the functional and structural performance of the product, Galjaard says.

Still, the designers spent much more time working with the complex, optimization software than they normally would, and the process could be frustrating, she says.

“Our research illustrates that 3D printing can have a positive impact on the design and production process and the functional product,” she says. “The resulting costs of future construction products could be decreased significantly, whereas architectural freedom will be increased dramatically.”

Generative design and topology optimization can bring the same design freedom and cost reduction to engineering and other types of design of course. Imagine a complex, oddly shaped part that is printed and performs as an assembly. In other words, a part beyond your imagining. That’s the promise of generative design and topology optimization.

Altair
www.altair.com

Autodesk
www.autodesk.com

Dassault Systèmes
www.3ds.com

Siemens PLM Software
www.plm.automation.siemens.com

Can you find gold in IronCAD?

May 24, 2018 By Leslie Langnau Leave a Comment

Phil Foley, Contributor

When reviewing new software, I’m always carful not trust my first impressions as they can prevent you from seeing important features and capabilities. With IronCAD this rule of thumb was important.

In reviewing IronCAD I was surprised at how cool and powerful it was. IronCAD reminds me of many cad packages. It feels like AutoCAD was out drinking with 3dsMax, and Inventor felt cheated on by AutoCAD so it started dating Rhino3D. Revit called IronCAD to get together, and while they were driving to the movies their car was hit by Sketchup. The surface models of the cars did a Fusion 360 and due to IronCAD’s Houdini driving they were fine. After the movie they got pizza and Draft Sight. Onshape walked in to the pizza joint and everyone else was jealous because Onshape was the only one that had web access.

For the record, I am wary of software packages that rename functions, sketch commands or features that are the cornerstone of computer aided design. An example of this is the Fillet command; in IronCAD it’s called Blend Edges.

As an engineer, when I see this I get a bit worried that the software is being developed by non-engineers. I love development and enjoy breaking paradigms within design of machines, products and robotics. However, there are some paradigms that should almost never change. I really can’t believe I said that! When companies compete to convert users from one 3D package to the next its critical that the initial learning curve isn’t too steep. The quickest way to lose the attention of a new potential user is to rename items such as Fillet to something fluffy like Blend Edges.

One other feature I historically dislike has been drag and drop features; maybe because it reminds me of using TinkerCad. I feel TinkerCad is the annoying little brother of all the other parametric modelers. It’s like if AutoCAD and Inventor were going to the park to shoot hoop with their friends, Solidworks and Onshape, and Mom makes them take their annoying little brother, TinkerCad.

That said, I’m glad I broke through the TinkerCad viewpoint and gave IronCAD Drag and Drop Modeling a try. It’s a slight departure in my typical design flow, however, it was a great time saver and they may have converted me. If you give it a try I think you will incorporate this into your future workflows. I am looking forward to spending more time exploring IronCAD.

But I think there is an identity crisis with IronCAD. I thought I was opening a modeling package specifically developed for mechanical engineers designing sheet metal parts, machines, and products, however, it’s so much more. This package is extremely flexible for mechanical engineers, architects, game developers, animators and product rendering specialists.

Using IronCAD’s Catalog Browser, I opened every tab as if I were exploring a new frontier. The list of shipped catalogs was expansive and fun to review. The tabs are located at the bottom right of the screen, which allows for quick access to your most useful 3D models.

In IronCAD’s Catalog Browser, tabs are located at the bottom right of the screen, which allows for quick access to your most useful 3D models.

I initially didn’t like the Selector Wheel because I was expecting different right click results, but continued to use it, and found it useful. This can be turned off and edited as well.
IronCAD puts out regular improvement updates, and they are free! There website is clean and organized showing summary updates and product offerings.

The Export options were not vast like Rhino3D, but they hit all the standards and a few surprises such as Visual Basic files, 3D PDFs and Raw Triangles. IronCAD has been built to be flexible and scalable. Add-Ons are available for several CAD packages such as CATIA, Solidworks, SolidEdge, Pro /E and Inventor. They also offer a Native CAD Translators that run alongside with IronCAD that I’m excited to check out.

The IronCAD package competes with all the heavy weights in the industry, however, their product offerings and price tags are the best in the industry. I looked up pricing as it’s not listed on the IronCAD site and here’s what I found.

IronCAD Draft: $559
IronCAD Inovate: $1,199
IronCAD Inovate/USB dongle: $1,395
IronCAD PRO XT: $615
IronCAD Translate Add-On: $659

One of my favorite features in IronCAD was the ability to Save All as External, which will create a new single file for each part within your design and locate in a selected directory. In the early days of parametric modeling this was a chore. However, today we see similar functions in Solidworks such as Pack-and-Go. I opened the Awards tab in the Catalog Browser, dragged in every model and then used the Save All as External, Selected the destination folder and presto!, it created a nice neat directory of every model.

A key feature in IronCAD is the ability to Save All as External, which will create a new single file for each part within your design and locate it in a selected directory. In this example, using the Awards tab in the Catalog Browser, I dragged in every model and then used the Save All as External, Selected the destination folder it created a nice neat directory of every model.

To sum up my experience of IronCAD; it exceeded my expectations and left me wanting more.

IronCAD
www.ironcad.com

Innovative motor designs for electric cars come to life through Multiphysics

February 22, 2018 By Leslie Langnau Leave a Comment

The automotive industry is in the midst of a disruption, and the transcendence of electric vehicles from niche to mainstream products is a driving force behind this change.

Yet challenges remain to improve the motor designs used in electric vehicles. One potential solution is the use of Power Magnetic Devices (PMDs), a category of devices that include motors, generators, transformers and inductors. In simple terms, these components use an electromagnetic field to convert electrical energy to mechanical energy, or vice versa.

In the field of power engineering, and particularly in the design of PMDs, modern advances are targeted at reducing system losses, mass, volume, and cost, while simultaneously increasing power capability, reliability, and large-scale manufacturability.

Modeling, optimization, and collaboration come together

Achieving these competing objectives in modern applications requires advanced methods to optimize the design of various PMDs such as electric motors. These include computationally efficient device models in conjunction with state-of-the-art optimization techniques. Furthermore, the design constraints pertaining to electric motors represent a complex multiphysics problem from a mechanical, electrical, and thermal perspective. (Figure 1)

Figure 1. Finite element analysis (FEA) of a nonlinear-surface permanent magnet synchronous motor (PMSM)

Faraday Future, a start-up technology company focused on the development of intelligent electric vehicles, is using COMSOL Multiphysics software, a multiphysics finite element analysis program, to produce state-of-the-art electric motors with high power density.

The organization is also taking an innovative, modular approach to electric vehicle design. Omar Laldin, Lead Electromagnetic Engineer at Faraday Future, explained: “My group develops motor designs for a generic set of vehicles, primarily suited to our variable platform architecture, which allows for modular development of electric vehicle powertrains. We can add or remove motors, adjust battery quantities, and collapse or increase the size of the chassis.”

“To be able to do that, we have to design the motor for a variety of conditions, and need to take into account several different aspects of the motors beyond just the electromagnetic components, such as the mechanical and thermal behavior,” Laldin added. Figure 1 shows an example of an electromagnetic analysis conducted by the group.

This involves completing a series of advanced optimization algorithms, which quickly model how particular designs will behave. Speed is important as these optimization algorithms must be run over numerous iterations to ensure a variety of designs are investigated. As a result, some aspects of the models need to be simplified.

Laldin explained: “It could take several weeks to do a full CFD analysis to predict thermal behavior. There are often thousands of designs to be considered, and hundreds of operating points for every given design, making it impractical to do detailed multiphysics analysis with a computationally heavy tool. Tools like COMSOL, which allow us to conduct thorough electromagnetic and mechanical analyses along with simplified thermal analysis, work in a very stable way and give us quick feedback on each of these aspects during the design process.”

The versatility of COMSOL also helps the Electromagnetic Motor Design Group collaborate with the other teams within Faraday Future, including Motor Mechanical, Inverter, Motor Control, Powertrain Control, Systems Engineering, and so forth. Collectively, these groups form the Powertrain Group within the organization.

“We do all the early stage analysis before we send data to other teams to make sure we’re in the right ballpark, and that limits the number of iterations we have to do with other teams. I think that’s one of the most beneficial aspects of the COMSOL simulation and modeling tools,” he added.

Designing an actuator

The EM team designed an EI-core actuator to meet certain constraints, while obtaining the compromise between competing volume and power loss objectives. While the power loss must be minimized, they did not want to increase the size of the component to do so, as package size is a critical metric in most vehicular systems. The actuator was made up of a coil of conducting wire wrapped around a stationary E-core, along with a movable I-core (Figure 2).

They performed a 2D electromagnetic field analysis in COMSOL, coupled with a genetic algorithm implemented in MATLAB software. The model accounted for the highly nonlinear behavior of the various steel materials, while the genetic algorithm provided the globally optimized and multi-objective “Pareto-Optimal Fronts,” which provided the tradeoff between reducing the volume and power loss (Figure 3).

Top: Pareto-Optimal Front providing mass vs. loss tradeoff. Bottom: Magnetic flux distribution in the EI-core actuator.

They used geometric parameters of the actuator as inputs in the algorithm, and obtained losses based on the coil resistance. This allowed for the rapid investigation of numerous designs of the electromagnetic actuator, capable of delivering 2500 N of force.

Investigating losses

The team investigated the nonlinearity of the steel used in electric motors, which changes the nature of high frequency conductor losses in a slot. These losses increase at high speeds due to the increase in skin and proximity effect in the conductors, they are also affected by the temperature. Due to the geometry of the motor, some winding architectures and their conductors are more easily cooled than others. For example, the spacing of the conductors and their dimensions can affect the heat transfer in the slot.

Laldin and his colleagues performed further multiphysics analysis coupling the electromagnetic components with the thermal behavior to identify hotspots in the motor that could cause catastrophic failure. They discovered that the current density within the conductors changed significantly due to changes in flux density across the slot. They calculated the loss density in each of the conductors and then obtained the temperature distribution, which provided the maximum hot spot temperatures in different areas of the motor (Figure 4).

Temperature. Model geometry, magnetic flux, current density, power loss, and temperature distribution in a model of a stator slot.

Laldin said: “The loss in different conductors can differ even if we have the same current. We model these variations and do some approximate and quick thermal analysis in COMSOL, which allows us to study the temperature distribution.”

By identifying the maximum hot spot temperatures, this enables manufacturers to determine the reliability of the design and prevent destructive motor events.

This multiphysics approach brings further time savings to Faraday Future as one person can both design and analyze a motor and its components. Laldin said: “Instead of doing 10 iterations with the various teams, our tools allow us to complete the design in 1 to 2 iterations. This is one of the biggest advantages of having a multiphysics analysis tool—we can cut down on the number of iterations we need to do between different groups. It’s a lot quicker for one person to optimize the design, followed by minor refinements across the teams, than it is for each team to independently analyze each aspect of the physics.”

Application exchange for the future

Faraday Future is a relatively young company, and yet it has achieved great strides in the electric vehicle sector as it designed, developed, and constructed a working electric vehicle within just two years. The organization has embraced COMSOL’s Application Exchange, an online community where users can upload and share their models, and discuss techniques and findings with other users, to help fuel this growth. Laldin said: “The only realistic way to achieve such innovation is to use the experience of our suppliers and the capabilities they have. In a user community, it’s a lot easier to find solutions to the tool for problems that we all have in the field.”

Laldin added: “COMSOL was a very natural choice for us as we are developing state-of-the-art technologies and appreciate the need for speed. For example, if I need a new feature in the software, the company is very responsive in including that feature in the next release.”

COMSOL’s open and responsive Application Exchange platform will also help Faraday Future keep ahead of the competition, as Laldin added: “On top of that, fostering this online community fits with the startup mentality where you’re willing to contribute non-sensitive data and know-how in an open exchange for the benefit of everyone involved. I have always felt that you always get more out of user communities and the exchange than what you put into it, especially when it’s backed by a state-of-the-art industrial partner. It’s a very good combination for a company like ours.”

COMSOL
www.comsol.com

Iowa State University’s Formula SAE team uses solidThinking Inspire to slash weight of rear aerodynamic wing

January 29, 2018 By Leslie Langnau Leave a Comment

Bruce Jenkins | Ora Research

Cyclone Racing, Iowa State University’s Formula SAE team, consists of 40+ active members who design, build, test and race a formula-style race car each year to compete with approximately 80 teams representing seven different countries at the Formula Lincoln event and some 30 different teams at the Formula North event. Cyclone Racing is currently ranked fourth in the United States and fourteenth in the world out of 550 teams. Most aspects of being a professional racing team are evaluated and judged, and the team operates largely from private sponsorship with support from Iowa State University. Teams must demonstrate a top-performing racing machine on the track, and also demonstrate their working knowledge of both engineering and marketing through a series of presentation events.

When designing their latest vehicle, CR22, one of the team’s goals was to reduce the weight of the vehicle’s rear aerodynamic wing. Nate Lenz, Cyclone Racing’s Technical Director at the time, noted, “With last year’s car, the internal wing structure was very heavy, to the point that we would see some very excessive roll, and a few times, even though the car was super-fast, we would find ourselves up on two wheels. Keeping that in mind, a huge goal with this year’s car was to reduce the weight of the entire wing package, while also ensuring that it was very strong and stiff.”

Nate first learned about solidThinking Inspire from a flyer he saw posted on campus. “It immediately caught my attention,” he said, “and I thought it was fascinating, but other priorities came up and I did not have a chance to try it at that time.” When the project to redesign the bracket mount for the rear wing package came up, Nate immediately thought of Inspire. “Knowing that the mount had to be extremely light, while also being as stiff as possible, it seemed like a perfect project to try Inspire on. After struggling to complete the project with some other tools, I downloaded solidThinking Inspire.”

solidThinking Inspire in the design process

The first step in using Inspire was to learn how to use the tool successfully. Nate mentioned, “Inspire was very intuitive to learn— it honestly only took about five hours of working through the tutorial models for me to become comfortable with using the tool.” Once confident enough with the tool and its capabilities, the team created an initial design space for the brackets in an external CAD tool. “This particular beam was unique in that it had to stretch over a long distance, be high off the ground, and put under a bending load. The nice thing with it was that we were only constrained by the mounting locations, so we were able to work through a few different design space options, as well as loading scenarios, prior to ending up on the final design.” After running through a number of different iterations in Inspire, the team was able to select a final optimized design for the bracket which it then used Inspire, as well as third-party analysis and verification tools in order to simulate and analyze the performance of the part.

Mount design space and loads setup in Inspire.

After the design was verified, the team moved into the manufacturing process, where the new brackets were manufactured using waterjet cutting—which was not only quick but also very cost-effective. Nate mentioned, “I really liked being able to set the different manufacturing and symmetry constraints in Inspire. This allowed us to design the part specifically for the manufacturing process we wanted to use.”

Results

New optimized mount design and analysis in Inspire.

The new swan-neck wing mounts were a great success. Not only did Inspire allow the team to design these parts for the specific manufacturing process they wanted to use—waterjet cutting—it also enabled them to significantly reduce the weight of the entire wing package from approximately seven pounds to four. “The weight reduction in the mounts was significant,” Nate reported. “We even went from a hollow wing last year to a foam-filled wing this year, which increased its weight, so the reduction in weight for the mounts was imperative. This ultimately helped reduce the weight of the entire car, and helped us perform better in competition. The mounts were not only very light, they were also very stiff and survived all of the rigors that our competitions put on them. My teammates regularly come up to me now and say, ‘Hey, Nate, can you solidThinking this part for us?’”

Full wing structure including optimized swan-neck mounts.

What’s next?

Today Nate is on the senior design team of Cyclone Racing, where he and the team are currently working on some new and exciting projects. “We plan to continue to use Inspire,” he says. “Right now we are completely looking to redesign the car’s differential. This will be integrated into the car with a number of new mounts, as we will be going from a floating differential and floating engine, to now having them mounted in-between each other. We are working on taking the new loads from the chain tension and applying these in Inspire to generate and design all of the new mounts, which will be water-jetted or machined.” Nate also mentions that a number of other teammates are working on learning Inspire so Cyclone racing can use and reap the benefits of using the tool into the future.

About Iowa State University

Iowa State University SAE International is a student organization of five teams: Baja, Clean Snowmobile Challenge, Aero, Formula and Supermileage. Iowa State University SAE International’s mission is to expand upon the ISU classroom education through participation, leadership, outreach, design and fabrication in the Baja, Clean Snowmobile, Formula and Supermileage SAE Collegiate Design Series competitions. These internationally sanctioned competitions allow colleges from around the world to compete every year.

Iowa State University SAE 2025 Black Engineering, Ames, IA 50011

stuorgs.engineering.iastate.edu/sae/

http://forum.solidthinking.com/

Is SolidWorks CAM Better Than an Integrated System?

December 15, 2017 By Leslie Langnau Leave a Comment

When the engineering software vendor announced it was moving from integrated CAM to a total CAD/CAM solution industry watchers took note.

Jean Thilmany, Contributing Editor

For engineers and design companies, it’s not difficult to find integrated computer-aided design and computer-aided manufacturing technologies. Yet, the announcement of SolidWorks CAM, released in October as a SolidWorks 2018 add-on, has created a small buzz in engineering technology circles.

Why?

It’s no secret that engineers struggle to create designs that are easy to manufacture while machinists complain about receiving unworkable CAD models.

An imperfect fit

CAM software uses the CAD models to generate the toolpaths that drive computer numerically controlled manufacturing machines. Engineers and designers who use CAM can evaluate designs earlier in the design process to ensure they can be manufactured, thus avoiding product costs and delays.

Without CAM, manufacturers can be on their own when programming machines to make the CAD model. And not all those who design in CAD enter design features into CAM to control the machine tools. Without CAM, manufacturers use the CAD design to program the tools themselves.

SolidWorks CAM could create codes for the end machine used for manufacturing.

“The general idea has been that engineers design something and then the manufacturing people eventually figure out how to manufacture it,” says Sandesh Joshi. “With integrated CAM, they’re not as disconnected as that, but there’s still a disconnect. This SolidWorks tool could close that disconnect.”

Closing the CAD/CAM disconnect

Joshi is chief executive officer at the CAD outsourcing firm Indovance. Previously, he spent six years on the SolidWorks research and development team.

The SolidWorks offering could ramp up the number of CAM users by making the tool available to more engineers and designers, Joshi says. The SolidWorks 2018 release marks the first time that SolidWorks is providing the CAM product as part of its design solution.

SolidWorks CAM is “powered by” CAMWorks, in the vendor’s parlance. Before the October release, CAMWorks, from HCL Technologies, was one of many third-party CAM tools available for integration with the vendor’s CAD program.

Of course other CAD vendors offer integrated CAD and CAM solutions.

Siemens PLM Software, for example, also offers CAMWorks as an embedded solution within its Solid Edge CAD program. NX CAM, also from Siemens PLM Software, is integrated with other NX solutions, which allows NC programmers and manufacturing engineers to associatively access design, assembly and drafting tools in a one part-manufacturing environment, according to that software maker. And CAM features are integrated into the Fusion 360 design tool from Autodesk.

But rather than taking on two separate software solutions, CAD and CAM can act as one system within SolidWorks CAM, Joshi says. That could make CAM easier and more straightforward to the software’s users.

The solution is fully integrated with SolidWorks so users need not leave the familiar SolidWorks environment, says Mike Buchli, senior SolidWorks product and portfolio manager. It supports feature recognition and can generate machining operations directly from native SolidWorks files or from imported data. Toolpaths are automatically updated based on changes to the model.

If SolidWorks 2018 engineers and designers feel they’re working within one integrated system–rather than two separate but connected software systems—they might begin to automatically use CAM and to consistently consider manufacturability as they design the product, he adds.

The vendor’s tool opens the way toward making CAM ubiquitous on engineers’ desktops, much as 3D CAD is now more-or-less used across an industry that once relied on 2D drawings, he said.

The part process from CAD to machining will never be a “one-click process,” Joshi says. But it certainly can become more streamlined through the use of a common CAD and CAM system.

“The difference is engineers would be using CAM as they design so manufacturability is easier,” he says.

“When we build assemblies, we have clash detection. Similarly, CAM gives us red flags for manufacturability right at he design stage, saves a lot of time and money,” Joshi says. “Today all design engineers don’t necessarily deal with CAM, so having access to that will help engineers design for manufacturing way ahead in the product design cycle.

SolidWorks CAM holds the potential for both designers and manufacturers–the possibility of a key to the elusive quest for CNC standardization.

“Some kind of machining cannot be done, and if that’s true it’s better to change the design right away rather than during the manufacturing process,” he says.

The system offers tools to validate and improve part and tool designs, including part-manufacturability checks and tool-motion simulation, Buchli says.

In a blog post introducing the tool, he outlined other benefits, such as the capability to:

–Recognize certain types of geometry to understand how those features will be manufactured, and how much it will cost to manufacture.

–Read tolerances and surface finishes and make decisions about how to manufacture the product

–Automatically apply best manufacturing strategies so manufacturing processes faster and more standard

–Automate quoting and compare it to traditional methods to ensure all aspects of the part are accounted for ahead of time

Fewer codes in the future?

The introduction of SolidWorks CAM holds the potential for another big benefit for both designers and manufacturers: the possibility of a key to the elusive quest for CNC standardization, Joshi says.

If the CAM tool becomes popular among SolidWorks users, Joshi can envision a day when the software automatically produces the G-codes that drive the machines that manufacture the part.

Right now, manufacturers struggle to drive their machining processes directly from their design software. The CAD systems don’t “speak the language” of various machines such as cutters and laser cutters, CNC mills and lathes.

“There are different flavors of G-codes depending on the CNC controller,” Joshi says. “The basic commands and operations generally will work on all machines but there are particular specialties and differences.

If SolidWorks CAM becomes widespread with designers who already use the vendor’s CAD program, the vendor “could potentially create codes for the end machine used for manufacturing,” Joshi adds. “The designer may not have to worry about that up front, but it makes manufacturing a lot smoother.”

With enough popularity, others will adopt those same end-machine codes, he says, creating a more-or-less-standard manufacturing-machine programming code.

And he knows of what he speaks. Currently, designers often rely on machinists and production engineers to develop strategies to effectively make the part.

“Job shops and manufacturing generate G-code for their CNC machine tools based on the CAD models they receive,” Joshi says.

Technologists at his company help interpret “on the back end” how to machine CAD designs, he says. He sees the issues manufacturers have with CAD designs.

“These companies get models from anybody and everybody and they don’t necessarily have all the types of CAD software. So they’re importing raw data rather than inclusive parametric models,” Joshi says. “It still works, but it’s more work.

“If the process is more integrated from end to end, it’s more likely to be seamless,” he adds. “If something has to be changed or modified it can be done quickly rather than going to engineering and coming back and being modified for machining.”

At SolidWorks World 2017, held last February, at which SolidWorks CAM was teased, Buchli related the benefits integrated CAD and CAM can mean for a company, specifically CP-Carillo, of Irvine, Calif., which makes pistons and connecting rods for high-performance race vehicles. The company saw a “significant increase in throughput” when using the then-integrated SolidWorks and CAMWorks, Buchli said in February.

Before using CAMWorks, the manufacturer input SolidWorks model geometry into the Mastercam program to create toolpaths and generate G-codes.

“We programmed each custom piston order manually, slowing down manufacturing,” says Karl Ramm, former CP-Carillo senior technology manager and project developer.

“Each job would take about 10 minutes for non-complex pistons and up to 40 minutes for complex pistons–and that’s programming time alone,” Ramm adds.

When the company brought in the integrated CAD and CAM solution, “custom orders that took days to design and program went down to hours,” Ramm says. “What used to take five to 15 minutes takes seconds now.”

The time-savings comes because the process is automated. Designers load custom criteria into a database and launch SolidWorks. The design application automatically pulls in that criteria and the designer can then create the new piece, which it transfers into CAMWorks. The CAM program then automatically generates new toolpaths and posts them to CNC machines in the shop, Ramm says.

The capability to share that kind of design and programming knowledge between engineering and manufacturing speaks to one of the biggest benefits of an integrated CAD and CAM system, Buchli says.

Another benefit is consistency of workflow. At CP-Carillo, custom orders always follow the same path. Design engineers and manufacturers know what’s expected of them when creating and manufacturing custom orders, Buchli adds.

SolidWorks CAM is much too new to see if any of Joshi’s predictions about standardization and popularity will play out.

But product lifecycle management consultancy CIMdata Inc. says it welcomes the decision to package and offer SolidWorks CAM.

“It protects the investment of CAMWorks users and adds proven CAM capabilities to SolidWorks,” according to a CIMdata statement.

While it remains to be seen if SolidWorks CAM is a step beyond the type of integrated CAD and CAM systems that exist today, Joshi and CIMdata are certain the engineering software vendor has taken a step in the direction down which the industry must travel to iron out disconnects between engineering and manufacturing and to save manufacturers costs and development time in the future.

Dassault Systemes SolidWorks Corporation
Solidworks.com

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