Good FEA Vendors Should Respond to Customer Requests for More Efficient Design Workflow

Michael L. Bussler
President
ALGOR, Inc.
Pittsburgh, PA

The more efficient the design workflow is, the faster companies can fulfill consumer needs and desires and the more competitive and profitable those companies can be. In order to get well-designed products to market quickly, engineers need effective Computer-Aided Engineering (CAE) software that supports an efficient design workflow. Effective CAE software requires a synergistic combination of many features and technologies that enable engineers to modify and analyze parts quickly and easily and offer tools to examine analysis results and determine how they may affect the overall design. 

A typical design workflow begins with the concept phase and quickly moves to part or assembly design with a CAD solid modeler. Working with CAD is a necessary function of CAE in today’s marketplace. While CAE systems have long used CAD geometry as a starting point for FEA, today’s CAE solutions work directly with the native CAD geometry, eliminating time-consuming geometrical errors due to translation to universal file formats. Some CAE vendors offer the convenience of full associativity to exchange data between CAD and CAE for each design modification.

ALGOR’s InCAD technology was used to capture this Bourdon tube pressure gauge model directly from Pro/ENGINEER without file translation. ALGOR’s single user interface with right-click application, modification and deletion of loads, constraints and FEA properties and one-step meshing enabled engineers to obtain an accurate finite element mesh of this model quickly.

Even at this early stage of the design workflow, the accuracy of the FEA model is as much of a consideration as speed. Automatic, one-step solid assembly meshing with surface-inward meshing technology puts the best-shaped elements on the surface where stresses tend to be highest and built-in element quality and aspect ratio checks eliminate the need for additional, transitional mesh enhancement. The more accurate the solid mesh on the first pass, the more time engineers can save because they can have greater confidence in the results. 

Additional finite element modeling options enable users to account for particular design features, use element types that most accurately reflect their geometry and take advantage of the processing speed associated with particular element types. These options may include a midplane mesh engine for automatically converting thin, solid parts into plate/shell elements; feature suppression, which enables engineers to specify the detail level of geometry needed by the CAE software; and a full library of available elements, such as 2-D, beams, trusses, plates, tetrahedron and bricks as well as linear and nonlinear engineering elements to simulate real parts. 

Streamlining the design workflow requires a CAE solution with an interface that will provide a high level of ease-of-use as the engineer moves from the design phase to the analysis and simulation phase. Single-interface FEA solutions offer extra flexibility for the design environment because engineers only need to learn to use one type of interface in order to take advantage of a broad range of meshing and analysis capabilities regardless of the CAD system. This type of a modern, Windows-style graphical user interfaces includes many easy-to-use features such as tree views that visually guide users to provide all necessary information, multiple view windows, docking toolbars and context-sensitive menus that are tailored to particular steps in the analysis process. 

Educational support within the software should include a built-in users’ guide containing up-to-date software operating and reference documentation organized using a process-oriented approach that provides detailed instruction on how to perform each type of analysis. Additional learning aids may include keystroke-specific tutorials and context-sensitive help that provides answers when users click on any field in a data input screen. The Internet can also provide additional support. The most effective way of supporting software on the Internet moves beyond static text and graphics and uses the latest in broadcast television quality Internet Webcasts for product demonstrations and training. Step-by-step, Internet-based distance learning instruction enables engineers to learn about using FEA software and general FEA concepts without incurring the costs of travel and time outside the office.

While easy-to-learn interfaces streamline the CAE process, the availability of the full breadth of analysis capabilities enables engineers to realize even greater benefits. A full suite of analysis tools is essential, including motion and mechanical simulation with linear and nonlinear material models, static stress with linear and nonlinear material models, linear dynamics, heat transfer, fluid flow, electrostatic, MEMS, full multiphysics, civil engineering and piping. Of these capabilities, motion and mechanical simulation with linear and nonlinear material models, such as Mechanical Event Simulation (MES) and multiphysics simulation have the greatest potential to save engineers time during the total design cycle. 

The mechanics of the Bourdon tube pressure gauge were simulated with ALGOR’s Mechanical Event Simulation software, which simultaneously replicates motion and stresses.

The advantage of MES and multiphysics lies in simulating real-world, real-time events, eliminating the need to make time-consuming assumptions, so an engineer can get analysis results in which he can be confident. MES replicates motion and resulting mechanical behavior with linear and nonlinear material models and, therefore, enables engineers to avoid the assumptions inherent in traditional analysis methods, such as imposing unnatural constraints and using rule-of-thumb methods to approximate applied loads. The combination of motion and stress analysis considering full inertial effects enables engineers to see motion and its results, such as impact, buckling, permanent deformation and additional displacement. Simulation of an entire multiphysics event instead of a single static stress analysis allows engineers to examine the effects of multiple physical phenomena interacting over time. By considering all applicable physical phenomena, failure due to factors such as heat or the flow of fluids can be eliminated earlier, resulting in less physical testing. 

ALGOR’s heat transfer analysis software calculated the temperatures experienced by an automotive exhaust header (upper left). The calculated temperatures were then used by ALGOR’s structural analysis software to determine the thermal-induced stresses of the header (lower right).

Making CAE results easy to understand and share with others is as important as making the software easy to use. In order to get products to market most efficiently, engineers must have tools that enable them to quickly and easily visualize analysis results so that they can determine what, if any, design changes should be made. Today’s feature-rich FEA software enables engineers to visualize findings such as stress and displacement using result contours to determine whether designs require further modification as well as precision contours to decide whether the mesh quality is sufficient for their accuracy needs. Display capabilities such as dynamic viewing are also standard features that help engineers to more quickly decide whether to go back to the drawing board or proceed to market. 

Once the engineer has analysis or simulation results, the process of refining the design begins. At this stage, full associativity is critical because changes to the CAD geometry will be automatically reflected in the FEA model. Furthermore, full associativity enables CAE vendors to also offer automatic design optimization tools. CAD-integrated, parametric shape optimization requires only the input of CAD geometry, the dimension of a part that needs to be optimized and design criteria, such as stress, temperature or frequency. The software then iteratively captures geometry; generates a high-quality solid mesh; performs an analysis; reviews results against the specified criteria; and updates the CAD geometry until the design criteria are met. With automated design optimization, the computer shoulders the burden of repetitive manual work and, therefore, frees engineers for higher-level tasks, thus increasing total productivity.

Most CAE solutions also include built-in, Internet-ready presentation tools that enable engineers to automatically generate HTML reports and publish them to internal or external web sites once results indicate that a design is modeled to specifications. These HTML reports can contain automatically produced images of result contours, graphs and animations of results over time and VRML files that enable others to view the model in 3-D over the Internet.

Most CAE solutions also include built-in, Internet-ready presentation tools that enable engineers to automatically generate HTML reports (upper left). In addition, today’s feature-rich FEA software enables engineers to visualize findings such as stress and displacement using result contours (upper right) or animations for viewing results over time (lower right).

The benefit of using any CAE solution is, of course, that digital means of optimizing designs reduces expensive, time-consuming physical prototype testing. When parts need to be verified by less physical prototype testing, costs and time-to-market are reduced. Because more realistic simulation methods such as MES and multiphysics provide more accurate and comprehensive analysis while requiring fewer assumptions, these methods have the potential to reduce prototype testing even more than traditional analysis methods do and can be performed by any level of engineer. As you can see, effective CAE software supports an efficient design workflow through a synergistic combination of many features and technologies that enable engineers to modify and analyze parts quickly and easily and then have tools to visualize analysis results.