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Leslie Langnau

How to combine 1D and 3D thermal simulation for modeling aircraft fuel systems

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Leveraging advanced 3D CAD-embedded CFD capabilities can add robustness and fidelity to a 1D system model.

By Mike Croegaert, Siemens Digital Industries Software

A common issue with modeling complex 1D systems is adding the required detail for complex components that cannot easily be represented through correlations or empirical data. To get the data for these types of components, engineers have two options: physical testing and 3D computational fluid dynamics (CFD) simulation and analysis. Physical testing can be costly and obtaining the data can be difficult for all possible operating scenarios. Whereas, 3D CFD can be time-consuming and often requires an expert to get reliable results.

Fortunately, we now have the option to use advanced 3D CAD-embedded CFD solutions in conjunction with 1D CFD tools to quickly and accurately characterize complex components without the need for a specialist, while providing an added level of robustness to a complex system model.

The basic fuel system: solving pump limitations
To illustrate the effectiveness of using this combination, a simple passenger aircraft fuel system example will be used. Figure 1 shows a 1D system model drawn on top of the basic fuel system schematic image. It includes source components for the boundary conditions and extra loss components for items such as filters and couplings. The thin link lines represent a direct connection between adjacent components, but they are not pipes themselves. Nodes sit in the middle of the links and serve as convenient points to enter elevation data and interrogate flow results of temperature and total pressure.

Figure 1: Basic aircraft fuel system schematic. The three large blue sections represent the wing and the center fuel tanks, the white boxes represent pumps, and the fuel feed and transfer plumbing is represented in green. The refueling lines are represented in dark blue. Shut-off valves are depicted throughout the model as the circular symbols, indicating normally open or closed.

During normal operation, the fuel is drawn from the tanks with mechanical fuel pumps. However, most mechanical pumps must be fully wetted to function properly. This means sometimes unusable fuel is left in the bottom of the tank. To extract the residual fuel, jet pumps can be added with the suction side connected to the lowest sump point on the inner wing tank. This pump feeds the collector cell by using the motive energy provided by a small amount of high-pressure fuel bled directly from the mechanical fuel pumps. For this example, the jet pumps are placed in the lowest portion of the tank.

In contrast to most other components, this jet pump does not come pre-supplied with performance data. That leaves the designer with two options to define performance. The first method is to enter detailed geometry for the pump and the 1D CFD tool can apply a built-in empirical correlation for jet pump behavior. The second option is a more rigorous databased approach. The pump requires a curve of flow ratio versus head ratio and a curve of motive flow rate versus pressure difference between the motive and suction arms. This data can come from many sources, including the vendor of the pump, physical testing, or 3D CFD characterization and analysis.

3D-1D characterization
Sophisticated 3D CAD-embedded CFD programs have key technologies that facilitate 1D data generation. These tools can be used by the typical engineer as well as seasoned CFD analysts. They apply automated modified wall functions to capture boundary layer effects properly, regardless of the density of the mesh in the boundary layer. They also have an automated solver to determine the flow regime between laminar, turbulent, or transitional without intervention. The most advanced 3D CAD-embedded CFD software has a unique and automated mesher that is geometry aware. If the CAD geometry changes, the mesh changes automatically, updating as the problem solves, intelligently putting more mesh where it is needed. Because these tools are completely CAD-embedded, the designer can run parametric studies, by not only varying flow conditions, but also changing the actual geometry over the course of a study, feeding data back to the 1D CFD software as seamlessly as possible.

Using an intuitive graphical interface, the designer inputs the key variables—choosing the units, the physics to consider in the simulation (including heat transfer, gravity effects and rotation), the fluids to use in the simulation, and lastly, the initial conditions such as temperature, pressure, and initial velocity. The 3D software then calculates a computational domain surrounding the relevant fluid geometry. The design engineer can resize the domain area or even slice the volume in half and do an axisymmetric simulation to save computational resources. The mesh (Figure 2), although highly automated, can be manually driven to add grid cells where needed and manually refined by selecting specific geometry, adding optional control planes, or even disabled bodies into the CAD model to serve as the mesh structure.

Figure 2: 3D CAD-embedded CFD adaptive mesh.

Once the model is prepared, the boundary conditions set, and goals determined, the simulation is ready to run launching the solver. The solver is the only aspect of 3D CAD-embedded CFD that does not operate directly in the CAD environment. Instead, a second window is launched to monitor the progress of the solution. Custom-defined preview plots for parameters such as pressure, velocity, and even the mesh can be created. Goals can also be plotted to have a real-time monitor on current value and their trend toward convergence. Parametric studies can also be performed on multiple machines at once to improve performance.

Once complete, the results are loaded back into the CAD interface, the first example of a result is a cut plot that shows the contours of velocity with overlaid streamlines (Figure 3). The cut plane can be manually adjusted with a live preview. 3D CAD-embedded CFD can also generate three dimensional flow trajectories inside of the fluid region.

Figure 3: Sample results from 3D CAD-embedded CFD.

Typically, for characterizing a component using 1D CFD software, multiple simulations are needed to generate data over a range of flow conditions. Once the study is complete, the results can be saved to a file that acts as a raw record of the flow conditions at each boundary at each experiment point. Each point contains data for flow rate, pressure, temperature, density, viscosity, enthalpy, and heat capacity. From this data, non-dimensional curves can be created so that the software can extrapolate performance of the part over a range of fluids, temperature, and pressures.

After the curves are created, they can be imported into the 1D CFD tool either as an individual data curve or as a complete component. The software will parse the data and automatically determine what type of component to create. Once this step is done, the 1D CFD software adds the component to the catalog and automatically populates it with the data just generated.

Before using the component in the fuel system model, it will first be verified in a unit test. Unlike most components, components sourced from the 3D CAD-embedded CFD program require no further data to use because relevant data such as the curves are pre-applied. All that is required to run a unit test is to add boundary conditions and run an analysis, and the component should perform exactly as the software predicted during the characterization step. After the unit test has verified the component was created correctly, the jet pump can be added to the fuel system model (Figure 4), and the designer can run a series of analyses.

Figure 4: Adding the characterized jet pump to the system model.

In this example, two transient simulation scenarios will be examined. In the first simulation, the jet pump has been included but blocked the motive flow, so the tanks will only feed into the collector cell via gravity. The connection between each section of the tanks is through a series of holes in the ribs that separate each compartment. These holes span almost the entire height of the tank, but the bottom 2-in. of the tank is blocked by structure.

As shown in Figure 5a with the blue line, the outer tank is draining briefly into the inner tank marked in red. The outer tank stops flowing as the level of fuel drops below the holes in the rib. Rendering the remaining 2-in. of fuel in that tank unusable. The inner tank in red, and the collector cell in green both drain together. The collector cell is drained via the mechanical fuel pumps, and the inner tank drains via gravity into the cell until it too reaches about 2 in. of height and can no longer drain. The tank is exhausted of all usable fuel in about 125 seconds.

Figure 5a: Scenario 1 – Jet pump inactive.
Figure 5b: Scenario 2 – Jet pump active.

The second case shown in Figure5b has the jet pump enabled. Here, the jet pump is moving fuel from the inner tank to the collector cell at a rate of about 10 gal per minute. In this case, the inner tank drains much faster, but that fuel is being transferred to the collector cell to feed the pumps. Because the suction inlet to the jet pump can be placed at the lowest point in the tank, it can drain almost all of the fuel out of it before it stops providing flow. At this point, the fuel level in the collector cell starts to drop quickly until it is completely exhausted. In this case, because more fuel is available, the tank does not drain for 320 seconds, a significant improvement.

Leveraging advanced 3D CAD-embedded CFD capabilities can add robustness and fidelity to a 1D system model. The 3D CFD solution does this by characterizing complex components within the CAD environment and then automatically importing the results into the 1D model. Here, a common issue with 1D system models of aircraft fuel systems was examined: how to add the required detail to the model for complex components that cannot easily be represented through correlations or empirical data. Siemens 3D CFD software, Simcenter FLOEFD, runs inside of several CAD packages including Siemens NX and Solid Edge, CATIA V5, PTC Creo, and a standalone version. This example also uses Siemens Flomaster 1D CFD software for the system simulation.

Until recently, designers had to choose between costly physical testing and time-consuming 3D CFD that usually requires an expert to obtain reliable results. This approach that combines 3D CAD-embedded CFD and 1D CFD can be used to quickly and accurately characterize complex components without the need for a CFD analyst and provide an added level of robustness to complex models such as the aircraft fuel system.

Siemens Digital Industries Software
www.sw.siemens.com

IronCAD launches Design Collaboration Suite 2020

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IronCAD, the 3D CAD platform of choice among metal fabricators and custom machinery manufacturers, unveiled IRONCAD 2020 and it’s got more than just perfect vision for design productivity. Designed to increase productivity for CAD software users to get their products to market faster, this release focuses on performance, commonly asked usability items, and continued improvements on key functionality that sets IronCAD apart in the design process.

Every year, IronCAD users submit feedback with enhancement requests that matter the most for increasing the design productivity or improving the 3D to production drawing process. The IRONCAD 2020 release delivers improved large assembly performance, streamlined workflows, and new capabilities that help users design, present, and communicate their ideas faster and easier. This year’s release, the main focus was on improving the ICD (IronCAD Drawing Environment) to increase productivity. With this in mind, our goal was to improve the 3D to 2D detailing process to reduce the design to manufacturing timing with better performance, improved commands, better accessibility to common commands, faster drawing creation with our automated bulk view creation tool that enable users to go from concept to manufactured products faster.

Beyond the IronCAD Drawing Environment, IronCAD delivered performance improvements for working with large assemblies. This significant development was implemented to increase the system’s performance and to take advantage of newer hardware with multiple cores. In addition, many functional items were added to streamline the interaction with large assemblies, such as additional improvements in our Shrink Wrap commands for condensing large assemblies into workable reference geometry. With IronCAD 2020, noticeable improvements can be found importing, opening, saving, and working daily with large assembly files.

Examples amongst the new improvements in IRONCAD 2020 are:

· Large Assembly Performance – Open/Save/Import speed is improved for files that contain large structures that may have large assembly trees containing many nodes under individual assembly levels. Changes implemented have significant improvements in speed in all areas while working on large assemblies that range from 30-50% improvement.

· Real-time Interchanging of Full and Lightweight Models – Using IronCAD’s Shrink Wrap capabilities to create lightweight versions of parts and assemblies, you can dynamically interchange the fully detailed model and the lightweight model within an assembly file. This capability significantly improves the interaction with large assemblies not only on load/save but while design within the context of the full assembly.

· Many Technical Drawing/Detailing Improvements – IronCAD 2020 focused heavily on improving the speed from taking 3D Designs into production drawings ready for manufacturing. Speed improvements in creating and editing dimensions with quick access to dimension properties, Automatic Break Line support, Overall View Dimensions, 2D Catalogs support for reusable Annotations, and Spell Checker are among some of the many improvements added to improve the process.

· Commonly Requested Functionality – Focus was given to provide functionality commonly requested by our industry users. Command Search, Dockable Catalogs, 4K Support, Feature Fill Pattern, Sheet Metal Conversion and Layflat Design feature are among items added to enhance the design experience with IronCAD.

“Expanding on our recent 20th year release capabilities, IronCAD 2020 gains a significant leap in the ability to work and manage large assembly files commonly used among our custom machinery manufacturers” stated Cary O’Connor, V.P. of Marketing of IronCAD. “Users will feel improvements to the performance while working in 3D all the way through to the final production drawing output with the many improvements developed in the IronCAD Drawing Environment to speed up and aid the detailing process” he continued.

IronCAD
www.ironcad.com

Meshmatic optimizes CAD files for real-time visualization

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Meshmatic is a 3D optimization software that helps engineers prepare design files for real-time visualization faster. A challenge with many large and complex engineering files is having to manually clean and optimize them for 3D rendering or AR/VR development. Such tasks are often repetitive and tedious, as well as prone to human error.

Meshmatic is standalone software that automates tedious optimization tasks and helps companies save time when cleaning up heavy and complex design files for simulation and AR/VR applications. It works with applications such as Keyshot and V-ray or game engines like Unreal Engine or Unity.

The software’s proprietary algorithms mathematically calculate the rotation, position, and scale of each of the 3D objects in a scene and groups them for duplicate instantiation or further modification. This method of calculation is useful for CAD conversions such as FBX or OBJ, with reset transformation.

Meshmatic reads 3D data from common file formats such as FBX, OBJ, STL, Sketchup, STEP and more, and processes them as polygonal mesh without harming shape integrity. Multiple data clean-up tools help users efficiently reduce file complexity without compromising the quality of the visualization or accuracy of the data.

In addition to its mesh, hierarchy clean-up and duplicate optimization tools, Meshmatic is equipped with data analysis tools to identify bottlenecks and errors in a file, which can be resolved with suggestive actions. The software also provides updates on file parameters such as file size, vertex count, face count, and more to help users track performance improvement during the clean-up and optimization process.

VRSquare
meshmatic3d.com

Better analysis of mixed fluid-particle interactions

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Cradle Software, part of Hexagon’s Manufacturing Intelligence division, announced advanced co-simulation and post-processing capabilities that make it easier for engineers to analyze multi-physics problems and mixed fluid-particle interactions.

The Cradle CFD v2020 suite comprises scSTREAM (structured mesh) and scFLOW (next-generation unstructured mesh) Computational Fluid Dynamics (CFD) technology. Cradle combines open cosimulation with the scPOST postprocessor.

New aero-acoustics simulation in Cradle CFD v2020 analyzes flow-induced noise in scFLOW by seamlessly connecting to the Actran acoustics simulation software through a dedicated plugin. It enables users to simulate aeroacoustics such as the noise from a car door mirror in a single software environment without learning to use acoustics software or spend time coupling systems.

Another development adds Discrete Element Method (DEM) to CFD and thermal dynamics within the scFLOW environment, reducing the complexity and manual work required to simulate fluids with particles. For example, optimizing the energy and water usage of a washing machine. Using the DEM feature, it is possible to evaluate heat transfer and filtering in isolation, or combine it with CFD analysis and other physics types.

Integration with system modeling software is also enhanced. Building on the open Functional Mockup Interface (FMI) integration already provided, Cradle now connects directly with more 1-D simulation tools. This enables customers to model complete products including electrical and mechanical subsystems in conjunction with the software’s built-in thermodynamics. Customers can easily map the heat transfer between electrical components using Cradle’s HeatPathView tool to visualize these multi-physics interactions. For example, providing optimization of heat routes in consumer electrical goods to enable system-level decision making with Maplesim or other 1-D simulation tools.

Noise from Door Mirror calculated by scFLOW2Actran.

Cosimulation with MSC Software simulation solutions including MSC Nastran, Marc and Adams have also been enhanced to rapidly generate high quality static and dynamic visualizations in scPOST. Cradle, and all MSC Software products including Actran can be accessed through the MSC One token-based licensing system so it is easy for anyone to access and use any tool to produce more realistic multi-physics simulations.

scPOST also makes product and engineering design reviews more accessible for designers, customers or business management. Any simulation through video export, virtual reality or interactive 3D models.

Cradle v2020 is available from today.

Hexagon | Cradle Software
www.mscsoftware.com/product/software-cradle
www.cradle-cfd.com

nTop Platform 2.0 overcomes the geometry bottleneck

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nTopology announces the latest version of its computational-modeling software, nTop Platform 2.0, an engineering software that enables engineers to simultaneously consider geometry, performance and manufacturability within a single, reusable workflow. This release includes support for prepackaged, application-specific nTop Toolkits, letting engineers quickly learn and use its capabilities right out of the box.

nTop Platform was developed to solve engineering problems where geometry is a bottleneck. It can handle complexity and iteration with speed and ease. The prepackaged Toolkits and authoring capabilities can be used to automate engineering workflows, delivering efficiencies and scaling an organization’s best talent across the enterprise. With nTop Platform, teams can automate tasks that take hours, days or weeks with traditional design tools because of the ability to build reusable workflows.

nTopology is also partnering with industry leaders in additive manufacturing hardware to deliver new capabilities to their users. “The flexibility and high performance of nTopology software and its ability to package-up customer workflows helps us and our customers to create advanced Digital Foam,” says Fabian Krauss, Global Business Development Manager at EOS. “We use it in projects to create 3D-printed products with architected materials properties tailored to customer needs. It unlocks the true potential of generative design in additive manufacturing for Digital Foam and for many other applications.”

In addition to the new prepackaged Toolkits, nTop Platform’s authoring capabilities allow a company’s engineers to create their own proprietary toolkits, enabling secure knowledge transfer across the organization.

Lightweighting Toolkit
● Quickly and easily reduce the weight and maximize the performance of parts.
● Shell parts in seconds no matter how complex the geometry.
● Apply variable wall thickness to shelled parts.

Architected Materials Toolkit
● Engineer functional materials that perform at any scale—hundreds of unit cells, or hundreds of billions.
● Design with multifunctional requirements from the start. Structural, thermal, acoustics, or aesthetics; all with total control at any length scale.
● Optimize unit cells to create unique material properties to perfectly suit the application. Increase surface area while reducing weight. Turn geometric complexity into a competitive advantage.

Design Analysis Toolkit
● Use fully integrated simulation capabilities to seamlessly analyze parts in a single, connected workflow.
● Drive geometric parameters directly from simulation results to achieve high-performance parts that meet functional requirements.
● Integrate with the simulation tools an organization already uses, including ANSYS, Abaqus, and Nastran.

Topology Optimization Toolkit
● Discover new and innovative designs early in the product development cycle.
● Apply multiple loading conditions and optimize for a variety of performance criteria including stress, displacement, stiffness, and weight.
● Use automated geometry reconstruction tools to quickly generate instantly editable geometry.

Additive Manufacturing Toolkit
● Position, orient and prepare parts for additive manufacturing from a set of common build platforms.
● Add lattice support structures easily and quickly
● Slice parts avoiding error-prone STL files and export manufacturing data directly to machines

nTopology
www.ntopology.com

COMSOL launches Version 5.5 of COMSOL Multiphysics

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COMSOL, a leading provider of software solutions for multiphysics modeling, simulation, and application design and deployment, announces the latest version of its COMSOL Multiphysics software. In version 5.5, the Design Module provides an entirely new sketching tool for easier creation and more versatile parametric control of geometry models. New and updated solvers speed up a range of simulations. Two new add-on products, the Porous Media Flow Module and the Metal Processing Module, further expand the product suite’s multiphysics modeling power.

Parametric sketching with dimensions
The Design Module provides a new sketching tool that makes it easy to assign dimensions and constraints to planar drawings for 2D models and 3D work planes. “We have carefully integrated the new dimensions and constraints tool in the Model Builder so that it becomes a natural part of the COMSOL Multiphysics workflow,” said Daniel Bertilsson, technology manager for mathematics and computer science at COMSOL. “The new tools for dimensions and constraints can be used together with model parameters in COMSOL Multiphysics to drive the simulation, whether for a single run, parametric sweep, or parametric optimization.”

Parametric optimization of fluid flow in a microvalve using the new sketching tool with dimensions and constraints capabilities available in the Design Module.

New solver technology for Acoustics Simulations
Ultrasound technology is becoming increasingly important in a range of applications spanning from process engineering and nondestructive testing to consumer electronics. New functionality based on the time-explicit discontinuous Galerkin method enables efficient multicore computations of ultrasound propagation in solids and fluids, including realistic materials featuring damping and anisotropy. The method also has low-frequency applications, such as in seismology. The included multiphysics capabilities can seamlessly combine linear elastic wave propagation in a solid and its transition to a fluid as an acoustic pressure wave, and back again. The new elastic wave functionality is available for users of the Structural Mechanics Module, MEMS Module, and Acoustics Module. The fluid-structure acoustics coupling is available in the Acoustics Module.

 

Sound pressure field in a car interior solved with the finite element method at 7 kHz using a specialized solver for wave propagation analysis.

For frequency-domain simulations, a specialized solver for wave propagation analysis makes it possible to handle higher frequencies (shorter wavelengths) using the finite element method. The new solver can be used to analyze enclosed structures such as that of a car cabin interior as well as other acoustics simulations.

Introducing the Metal Processing Module
The new Metal Processing Module makes metal phase transformation analysis accessible within the COMSOL Multiphysics environment for applications within welding, heat treatment, and metal additive manufacturing. “The Metal Processing Module makes it possible to predict deformations, stresses, and strains resulting from wanted or unwanted heat-driven phase changes in metals,” said Mats Danielsson, technical product manager at COMSOL. “The module can be combined with any of the other COMSOL products for virtually any kind of multiphysics analysis that includes metal phase change. We envision users combining this with, for example, the Heat Transfer Module for the influence of heat radiation, the Ac/dc Module for induction hardening, and the Nonlinear Structural Materials Module for highly predictive analysis of material behavior.”

 

Residual stresses in a spur gear after quenching, calculated using the Metal Processing Module.

Introducing the Porous Media Flow Module

The Porous Media Flow Module gives users within, for example, food, pharmaceutical, and biomedical industries a wide range of transport analysis capabilities for porous media. The new add-on product includes functionality for single- and multiphase flow in porous media, drying, and transport in fractures. The flow models cover linear and nonlinear flow in saturated and variably saturated media with special options for slow and fast porous media flows. The multiphysics simulation capabilities are extensive, with functionality that includes options for calculating effective thermal properties for multicomponent systems; poroelasticity; and transport of chemical species in solid, liquid, and gas phases.

Simulation of a packed bed latent heat storage tank, using the Porous Media Flow Module.

Simplified Shape and Topology Optimization with the Optimization Module
Users working with mechanical, acoustics, electromagnetics, heat, fluid, and chemical analysis have been able to perform shape and topology optimization in COMSOL Multiphysics for many years. The Optimization Module now offers simplified setup of shape optimization with new built-in features such as moving boundaries parameterized by polynomials and built-in support for shell thickness optimization. A new smoothing operation for topology optimization ensures higher-quality geometry outputs that can be used for additional analysis and additive manufacturing. COMSOL Multiphysics now has general support for import and export of the additive manufacturing formats PLY and 3MF, in addition to the STL format that is already available.

Shape optimization of a sheet metal bracket using the Optimization Module. The structure is subjected to a bending load resulting in ridges in the optimal design.

Nonlinear Shell Analysis, Pipe Mechanics, and Random Vibration Analysis
A wide range of nonlinear analysis options are now available for shells and composite shells, including plasticity, creep, viscoplasticity, viscoelasticity, hyperelasticity, and mechanical contact. The mechanical contact modeling functionality has been extended to support any combination of solids and shells, including solid-shell, solid-composite shell, and membrane-shell. Depending on the type of analysis, these improvements will be available to users of the Structural Mechanics Module, Nonlinear Structural Materials Module, and Composite Materials Module.

For users of the Structural Mechanics Module, a new user interface for pipe mechanics provides functionality to perform stress analysis of pipe systems. The new functionality can handle a variety of pipe cross sections and can include effects from external loads, internal pressure, axial drag forces, and temperature gradients through the pipe wall.

Users of the Structural Mechanics Module can now perform random vibration analysis to study the response to loads that are represented by their power spectral density (PSD).

This allows users to include loads that are random in nature, such as turbulent wind gusts or road-induced vibrations on a vehicle. The loads can be fully correlated, uncorrelated, or have a specific user-given correlation.

The Multibody Dynamics Module provides new functionality for analyzing rigid and elastic chain drives with automatic generation of the large number of links and joints needed for modeling chain drives.

 

Elastic chain drive analysis in the Multibody Dynamics Module. Colors and arrows show the velocity and velocity direction, respectively, in the chain and sprockets.

Compressible Euler Flow and Nonisothermal Large Eddy Simulations
Users of the CFD Module will get new interfaces for compressible Euler flow and nonisothermal large eddy simulations (LES). In addition, the flow interfaces for rotating machinery now support the level set and phase field methods as well as Euler–Euler and bubbly flow. The Heat Transfer Module comes with a new interface for lumped thermal systems, an equivalent circuit modeling approach for heat transfer simulations. Radiation in semitransparent (participating) media now supports multiple spectral bands, and a new open boundary formulation for convective flow reduces solution time by 30%.

Multiscale Wave and Ray Optics, Piezoelectric Shells, and PCB Ports
The Ray Optics Module can now be combined with the RF Module or Wave Optics Module for simultaneous full-wave and ray tracing simulations. This enables multiscale modeling, such as analyzing a waveguide beaming into a large room, where using a full-wave simulation would be computationally prohibitive. Combining the AC/DC Module and the Composite Materials Module, users can now analyze layered materials with both dielectric and piezoelectric layers in thin structures. In the RF Module, a set of new ports for vias and transmission lines makes setup much quicker and gives more control to the user for modeling of printed circuit boards.

Efficient Distribution of Standalone Applications
COMSOL Compiler enables you to create standalone applications based on COMSOL Multiphysics models with specialized user interfaces that have been built with the Application Builder. Compiled applications require only COMSOL Runtime — no COMSOL Multiphysics or COMSOL Server license is required. “Since the release of COMSOL Compiler last fall, we have seen great response from our Application Builder users with this new possibility of distributing their applications in standalone form,” said Daniel Ericsson, application product manager at COMSOL. The latest version of COMSOL Compiler has a new compile option for generating minimum-sized files for easier distribution. When the user launches an application for the first time, where the new compile option has been used, COMSOL Runtime is downloaded and installed, if needed, from COMSOL’s website. Only one instance of COMSOL Runtime is needed for applications using the same COMSOL version. COMSOL Runtime has a size of about 350 MB and an application file can be as small as a few MB.

The COMSOL Runtime installer for standalone applications created with the Application Builder and compiled with COMSOL Compiler.

Highlights in Version 5.5:

–New sketching tool with dimensions and constraints

–Fast linear elastic wave simulations

–New Metal Processing Module for welding, heat treatment, and metal additive manufacturing

–New Porous Media Flow Module for food, pharmaceutical, and biomedical industries

–Improved tools for shape and topology optimization for mechanical, acoustics, electromagnetics, heat, fluid, and chemical analysis

–Import and export of the 3D printing and additive manufacturing formats PLY and 3MF

–Editing tools for repair of STL, PLY, and 3MF files

–Structural analysis of nonlinear shells, pipe mechanics, random vibration, and chain drives

–Compressible Euler flow and nonisothermal large eddy simulation (LES)

–Rotating machinery with level set, phase field, Euler–Euler, and bubbly flow

–Lumped thermal system equivalent circuits

–Multiple spectral bands for radiation in participating media

–More efficient open boundary condition for convective heat transfer

–Use of thermodynamic database properties in any simulation type

–Combined full wave and ray optics simulations

–Piezoelectric and dielectric shells

–New PCB ports for vias and transmission lines

–Link images to Microsoft PowerPoint presentations

–Create your own add-ins for customizing the Model Builder workflow

–Minimal file size standalone applications with COMSOL Compiler

Availability
COMSOL Multiphysics, COMSOL Server, and COMSOL Compiler software products are supported on the following operating systems: Windows, Linux, and macOS. The Application Builder tool is supported in the Windows operating system.

To browse version 5.5 release highlights, visit: www.comsol.com/release/5.5

To download the latest version, visit: www.comsol.com/product-download

COMSOL

Developing a zero-emission, all-electric regional commuter aircraft

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Dassault Systèmes announced that the electric air mobility pioneer, Eviation Aircraft, used the 3DEXPERIENCE platform on the cloud to develop the first prototype of its zero-emission, all-electric regional commuter aircraft – Alice – in two years.

In the race to create and commercialize new categories of sustainable air mobility systems, Eviation Aircraft accelerated the prototype’s development by deploying the “Reinvent the Sky” industry solution experience based on the 3DEXPERIENCE platform. This scalable cloud solution supported the company’s holistic approach to 3D, composite design and flow simulation with improved collaboration while securing data in a single, standards-based environment.

“The electrification of aircraft isn’t a question of if, but when. As we aim to make clean regional air travel accessible for all, we needed to be able to make a product that people trust, sit in and fly, and do it quickly,” said Omer Bar-Yohay, CEO, Eviation Aircraft. “The right way to go about it was to use tools that we would want to use in the long run, and to work in the cloud to ensure fast, secure access and global collaboration. When we selected the 3DEXPERIENCE platform, we were an early-stage startup with limited resources and time. We’ve developed our commercial-stage prototype faster than we imagined, and have already signed our first customer in the U.S.”

Eviation Aircraft realized that transforming a prototype into a product that can be manufactured by the hundreds each year would require empowering its engineers with the long-term knowledge and know-how to build it to maturity for the next generation.

Once commercialized, Alice will be the world’s first all-electric regional commuter aircraft, capable of carrying nine passengers and two crew on a single charge for 650 miles at 10,000 feet.

Dassault Systèmes
www.3ds.com

Siemens expands SaaS offerings to Simcenter Amesim and Simcenter 3D

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Siemens Digital Industries Software announces the availability of Simcenter 3D software and Simcenter Amesim software delivered as a service. Through a strategic collaboration between Siemens and Rescale, a leader in enterprise big computing, engineers can gain immediate, cost-effective software-as-a-service (SaaS) access to simulation tools. Particularly useful for small to medium-sized businesses, the SaaS framework offers tiered product bundles in which customers can select the right level of capabilities they need, as well as monthly subscription-based billing and licensing and a pay-per-use computing infrastructure.

Large enterprises can also benefit from the availability of Simcenter on the Rescale cloud platform with multiple flexible licensing options available to solve specific business challenges. SaaS licensing can be used to add short-term software licenses in times of peak usage or bring your own licensing (BYOL) can be used to let Simcenter customers leverage their existing investments when high-performance computing (HPC) capabilities are needed.

Siemens is committed to using the cloud to deliver its software and make high quality simulation capabilities available to all businesses. In addition to Simcenter Amesim and Simcenter 3D, Simcenter Nastran and Simcenter STAR-CCM+ can be accessed through the cloud so that companies of all sizes can create and simulate digital twins of their products, on-demand on an established HPC platform.

Siemens Digital Industries Software
www.dex.siemens.com/plm/simcenter-on-the-cloud

PTC to acquire Onshape

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PTC announced that it has signed a definitive agreement to acquire Onshape, creators of Software as a Service (SaaS) product development platform that unites computer aided design (CAD) with data management and collaboration tools, for approximately $470 million, net of cash acquired.
The acquisition is expected to accelerate PTC’s ability to attract new customers with a SaaS-based product offering and position the company to capitalize on the inevitable industry transition to SaaS. Pending regulatory approval and satisfaction of other closing conditions, the transaction is expected to be completed in November 2019.

Located in Cambridge, MA, Onshape was founded in 2012 by CAD pioneers and tech legends, including Jon Hirschtick, John McEleney, and Dave Corcoran, inventors and former executives of SolidWorks. Onshape has secured more than $150 million in funding from leading venture capital firms and has more than 5,000 subscribers around the world. The company’s software offering is delivered in a SaaS model, making it accessible from any connected location or device, eliminating the need for costly hardware and administrative staff to maintain. Distributed and mobile teams of designers, engineers, and others can benefit from the product’s cloud nature, enabling them to improve collaboration and to dramatically reduce the time needed to bring new products to market – while simultaneously staying current with the latest software.

This acquisition is the logical next step in PTC’s overall evolution to a recurring revenue business model, the first step of which was the company’s transition to subscription licensing, completed in January 2019. The SaaS model, while nascent in the CAD and PLM market, is rapidly becoming industry best practice across most other software domains.

Onshape will operate as a business unit within PTC, with current management reporting directly to PTC President and CEO Jim Heppelmann.

Barclays acted as exclusive financial advisor to PTC on the transaction.

PTC
www.ptc.com

Parametric Modeling: still going strong thirty-one years on

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To get to parametric modeling and to the newer direct modeling, CAD has undergone such radical changes as to make the early systems look unrecognizable to today’s engineers. Here’s a quick review.

Jean Thilmany, Senior Editor

Last year, parametric modeling turned thirty.

“Parametric modeling made solid modeling practical for the first time and was a huge time saver,” says Jon Hirschtick, chief executive officer at OnShape, a CAD software company. “The beauty of feature-based parametric modeling was that engineers could create solid models with an ordered list of understandable modeling features like sketch, extrude, fillet, and shell. By changing dimension values—or adding, editing, reordering or deleting features—a solid part’s geometry would automatically update,” he says.

Now, direct modeling has joined parametric design as a model-building maneuver, and other techniques join their repertoire. Yet, parametric modeling continues to roll along. Mostly because, as Hirschtick points out, it works well.

To get to parametric modeling and to the newer direct modeling, CAD has undergone such radical changes as to make the early systems look unrecognizable to today’s engineers.

With the kinds of advances Hirschtick and others have made to CAD software through the years, it sometimes can be difficult to remember the technology has only been around since the 1960s, and parametric modeling since 1988.

The Wayback Machine
Ivan Sutherland is often credited with creating the modern graphical user interface and kicking off CAD. He essentially came up with the idea of drawing on a screen.

In 1963 while still a Ph.D. student at the Massachusetts Institute of Technology, Sutherland created his Sketchpad system, the first program to use a graphical user interface to interact with users. The program comprised an x-y plotter display and the recently invented light pen, a computer-input device shaped like a wand.

Ivan Sutherland created his Sketchpad system, the first program to use a graphical user interface to interact with users in 1963. The program comprised an x-y plotter display and the recently invented light pen, a computer-input device shaped like a wand.

“In the past, we have been writing letters to, rather than conferring with, our computers,” Sutherland wrote in his thesis. “For many types of communication, such as describing the shape of a mechanical part or the connections of an electrical circuit, typed statements can prove cumbersome. The Sketchpad system, by eliminating typed statements in favor of line drawings, opens up a new area of man-machine communication.”

Sutherland’s system displayed vector graphics rather than the raster graphics we’re used to today. Sketchpad users controlled the cathode ray tube’s electron beam via light pen to draw vectors on screen, creating shapes line by line. It was like operating a ray gun. You’d turn it on, draw a line, turn it off, move to the next point, and turn it on again in a process not entirely unlike the workings of an Etch-a-Sketch (which is, in fact, a simplified vector plotter), says Bernhard Bettig, a mechanical engineering professor at the West Virginia University who has taught a course on CAD history.

The phosphate that displayed the drawings tended to fade so users had to continually refresh the display. With very complicated displays they’d have to refresh often, he says. “And the system blinked a lot and when you got really complicated, you got a lot of blinking,” Bettig says. “But you still had lines on a screen, so it was a big deal.”

The systems allowed engineers to work out potential manufacturing errors on screen, to readily update their designs, and to render designs faster than they could by hand,” Bettig says. “These were wireframe drawings, which couldn’t depict volume and that could oftentimes lead to confusion.”

“Did a part open from the top, from the left, the right? It was ambiguous in terms of where the surfaces were. You didn’t know how to look at it,” he says.

The 1970s saw the advent of 3D modeling. Those early systems were based on solid modeling and stem from the work of two men on two continents who worked on separate approaches at about the same time. In 1976, mechanical engineering professor Herbert Voelcker’s group at the University of Rochester in New York used a process that came to be called constructive solid geometry, essentially a molding and joining of shapes.

Also in the middle 1970s, Ian Braid at Cambridge University in England released his solid modeler, Build, which delineated the boundary between solids and nonsolids to create models. As their methods varied, so did the eventual CAD systems based on those methods. Still, their underlying principle was much the same, writes David Weisberg in his 2008 self-published book “The Engineering Design Revolution: The People, Companies and Computer Systems that Changed Forever the Practice of Engineering.”

Yet, 3D CAD systems met with resistance from designers who said it was difficult to use.

“It was not until the introduction of parametric-based CAD that this resistance began to melt away,” writes Jami Shah in the book “Theoretical and Computational Basis Toward Advanced CAD Applications (Springer, 2001). Shah is an Ohio State University professor of engineering design.

In parametric design, the relationship between each element is used to inform the design of what will become complex geometries and structures. When using a CAD system driven by this method, engineers are called upon to build a geometry piece by piece, based on parameters like the depth of a hole, the diameter of a circle, or the thickness of a shape, Weisberg says.

One important and defining feature: the software tracks each step in the building process. When an engineer modifies the value of a dimension, the shape of the model changes accordingly. That single change can ripple through the model to automatically update each area affected. Engineers needn’t isolate and make those changes themselves.

In 1988, Parametric Technology Corporation, founded three years earlier by mathematician Samuel Geisberg, released the first commercially successful parametric modeling software, Pro/Engineer, Weisberg writes.
The goal was to create a system flexible enough to encourage engineers to consider a variety of designs, with the cost of making design changes as close to zero as possible, he says.

PTC Creo delivers a scalable range of 3D CAD product development packages and tools. Its variety of specific features and capabilities help engineers imagine, design, and create products better.

Pro/Engineer was implemented from the start as a solids-based system. Everything was done with double-precision solid geometry and NURBS surfaces.

To create a model, the user typically started by creating a profile of the object. This shape was then converted into a solid model by translating it through space or revolving it around a centerline. Additional geometry could be added or subtracted from the base model. Some of the geometry was in the form of features such as holes, bosses, and ribs, Weisberg writes.

“A key characteristic of Pro/Engineer was that as the model was created, the software recorded each step the operator took. This was referred to as a ‘history tree.’ The software also recoded geometric aspects of the model such as whether two surfaces were parallel or the fact that a hole was a specified distance from the edge of the part. Each dimension used to define the part was also recorded. If the user placed a through hole in a block and the thickness of the block was later increased,” he says.

The program was successful from the start in part because it didn’t have to support the legacy minicomputer and mainframe-based software that its competitors did at the time, Weisberg says.

“PTC developed Pro/Engineer from the start to be hosted on networked UNIX workstations. Its software was written in a higher-level language and the system used the latest software architecture techniques,” he writes.

Another modeling method
That’s the point at which things more or less rested until around the turn of the most recent century, which saw the introduction of a new method called direct modeling.

CAD systems driven by direct modeling don’t require engineers to use parameter-driven regenerations of a solid model. Instead, an engineer changes a solid model by pulling it, stretching it, and moving it as needed, rather like working directly with clay, says Holly Ault, mechanical engineering professor at Worcester Polytechnic Institute, Worcester, Mass.

Alternate terms for direct modeling include synchronous modeling and dynamic modeling, she adds.
“Direct modeling is an intuitive approach to creating geometry without the burden of history-based dependencies,” Ault says. “Construction methods are similar to those used in conventional solid modeling. The user can design a 2D profile and then develop the model using commands like extrude, revolve, mill, and bore. Without the presence of a parameterized history tree, manipulation of the geometry is greatly simplified.
The approach allows engineers to design directly on the model’s geometry, she adds.

Direct modeling creates geometry rather than features, so it’s prefect for conceptual modeling where the designer doesn’t want to be tied down with the interdependencies of features and the ramifications making a change might have,” Ault says.

CAD into the future
Of course, CADmakers don’t stand still. Many are looking at ways to include artificial intelligence to increase the ways engineers can use CAD tools for design.

Last year, for example, 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, who headed the product management team for Autodesk’s generative manufacturing solutions before moving last year to become director of product development at Roblox. The feature focuses on helping designers define the problem they’re trying to solve, he says.

“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.

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

CAD software will continue to evolve and who knows how AI will influence design. But it will be an interesting journey.