Siemens PLM Software Buyer’s guide for FEA software Tips to help you select an FEA solution siemens.com/plm/femap To enable effective finite NASA Goddard Space Flight Center – element modeling and James Webb Space Telescope analysis, don’t overlook Femap model courtesy of SGT Inc. the pre- and postprocessor part of the solution. This document gives you insight into what to look for and the many advantages that accrue from using a world class pre- and postprocessor. 2 “The benefits [of using a In selecting a finite element analysis conditions. The degree of control offered powerful pre- and (FEA) software solution, it is crucial that by the pre- and postprocessor is vital to postprocessor] include a you consider the pre- and postprocessor, increasing model quality while decreasing significantly reduced error which can be critical for the analysis analysis time. The risks of poor model rate for designs, greater speed and accuracy. FEA analysts rely on quality and accuracy increase as models product quality, and the pre- and postprocessor to work with and analyses grow in complexity. elimination of repairs an assortment of data files, provide a during manufacturing and variety of ways to idealize the model, This guide presents the critical role of the substantially reduced support one or more solvers and produce pre- and postprocessor in improving the costs.” the data and reports that are needed to accuracy of FEA results and making the Cui Zhongqin meet both internal and external most of engineering resources. Read this Chief Engineer requirements. Engineering managers rely guide to find out more about these top Baotou Hydraulic Machinery on the pre- and postprocessor solution to considerations: reduce the risks associated with accuracy • Accuracy while meeting time-critical product • User interface development deadlines. • Accessing CAD data • Understanding the results Although FEA solvers are tasked with • FE model creation and Idealization providing accurate results quickly, the • Automation and customization role of the pre- and postprocessor should • Solver support and solution scalability also be considered. The pre- and • Overall value and support postprocessor enables you to idealize a product model based on geometric information and then simulate how that model will behave under certain real-life 3 Role of the pre- and postprocessor and the FEA process The greatest challenge for engineering managers is mitigating The importance of meshing the FE model cannot be under- the risks inherent in any new product design. FEA technologies stated for both accuracy and speed. Figure 3 illustrates a mesh help enable significant reductions in risk, which is why they are convergence analysis in the preprocessor which can help deter- so widely used. Industry-leading pre- and postprocessing can mine an ideal mesh size for an analysis thereby minimizing run- provide an additional order-of-magnitude gain in analyses. The time while conserving accuracy. In a report titled “Cost Saving gains are in accuracy and control – simplifying and cleaning up Strategies for Engineering: Using Simulation to Make Better the geometry and the discretized data that goes into creating Decisions,” researchers at the Aberdeen Group, Boston, found the finite element model and ensuring that the calculated that engineers at 61 percent of the report’s “Best-in-Class” com- results are both understandable and relevant. Figure 1 illus- panies had significant control over meshing elements and his trates the role of the pre- and postprocessor and solver in the control was a contributing factor to the companies’ success. product design process. See a link to this report in the Other resources section. Preprocessor Analysis solution Finite element modeling Solver • Geometry editing • Apply loads • Apply contraints • Create FE model (mesh) Plate model 100mm x 100mm x 2mm • Define material properties fixed edges, pressure=1MPs (n=8 elements per edge) 1.1 Design feedback 1.0 0.9 Postprocessor 0.8 0.7 Geometry modeling (import from CAD system) 0.6 0.5 Figure 1: The finite element analysis process. 0.4 0.3 The role of the preprocessor, as seen in figure 2, is to import Maximum displacement (mm) 0.2 the geometry data, correct the geometry and discretize or 0.1 mesh it in order to idealize a physical design and create an FE 2 4 8 16 32 64 n model for analysis. Automation and customization capabilities provided by the preprocessor can help to speed up this pro- Figure 3: Mesh convergence analyses can help determine the cess. Following analysis by a solver, the postprocessor imports required model size to ensure accurate results. and displays the results in a graphical format and helps the understanding of model behavior. With a good understanding of the performance of the design from the analysis, the analyst may return to the preprocessor to further refine the model if necessary, and rerun the analysis. Solid Edge loads internal results NX Nastran SolidWorks constraints solver interpretation NEi Nastran NX materials technologies and correlation MSC Nastran Ideas TMG AutoCAD Engineering knowledge Adina Unigraphics Abaqus MicroStation Ansys Pro/E LS-Dyna Catia v4/v5 Sinda CAD Pre- and post Solvers Results processor Figure 2: The role of the FEA pre- and postprocessor. 4 Key questions for your software vendor Accuracy – Does the pre- and postprocessor enable you to control the FE model creation process sufficiently to ensure the creation of efficient FE models without sacrificing accuracy? Accessing CAD data – Can the pre-processor import and manage geometric data from multiple CAD systems and data formats? FE model creation and idealization – Does the pre- and postprocessor allow you to idealize certain topologies such as thin-walled models, and create smaller, more accurate finite element models? Solver support and solution scalability – Does the pre- and postprocessor support the export of solver input files and the import of solver results files? Can it support the parameters needed by industry-leading solvers? You should not only consider your current analysis needs but also compre- hend the potential scalability of the solution as new and unforeseen factors may lead to additional simulation requirements in the future. User interface – Does the user interface promote productivity in the use of the software and expedite learning? Understanding the results – Given the potentially huge amount of data that can be created by a finite element solution, it’s important to be able to quickly interpret results and gain an understand- ing of the model’s behavior for a quick analysis turnaround. Automation and customization – Does the pre- and postprocessor have built-in toolkits, macro creation capabilities and an application programming interface? Is knowledge capture possible and can workflows be automated and adapted to the organization’s processes? A pre- and postprocessor should be able to automate time-consuming tasks while also allowing the analyst to retain control of the adjustments made to the model and the steps of an FEA analysis. Can the pre- and postprocessor interact with third party programs? Overall value and support – Does the pre- and postprocessor vendor provide sufficient support to ensure maximum productivity? Does the vendor release regular software updates and do they provide useful new capabilities as well as error fixes? 5 Top pre- and postprocessor considerations “Creating advanced models These top considerations provide more encountered in generating an FE model that are both accurate and information and answers to the key from a CAD model. Left untouched, these fast definitely gives us a questions to ask your software vendor and similar geometry errors will degrade competitive edge and has when selecting an FEA solution. mesh quality and ultimately reduce become a critically important results accuracy and solution efficiency. contribution on these Accuracy The preprocessor should be able to effi- fast-paced, technically The preprocessor should provide the abil- ciently detect all such geometric irregu- challenging spacecraft ity to fully control creation and adjust- larities and repair or remove them from projects.” ment of the finite element mesh. That is, the model completely, while ensuring Jeff Preble meshing toolboxes should be available to that there is no consequential loss of President help create properly sized and shaped other associated model data, such as SpaceWorks Engineering elements in the right locations to ensure boundary condition definitions. that the final model will produce accurate “One single beam element results efficiently. In addition to CAD data access and replaces hundreds of solid import, the pre- and postprocessor elements. This is a definite Accessing CAD data should also have the ability to create and advantage of Femap. You can It may be possible to take advantage of manipulate geometry and finite element start your model from nodes the CAD model of the design to be ana- entities in the absence of any geometry. and elements and not just lyzed, and use it to create a finite ele- from solid geometry.” ment model. To this end, CAD data can The time taken to perform an analysis is be imported for meshing and idealiza- directly proportional to the model size as Alexander Naatje tion. CAD neutrality is important for a shown in figures 4 and 5. Model size is Project Engineer Femto Engineering BV standalone pre- and postprocessor, as dependent upon the number of node there are many different CAD programs points and their associated degrees of “Other products focus on auto- and data formats. The preprocessor freedom in a model. Certain topologies matic meshing of complex should be able to import geometric data can be idealized to significantly reduce mechanical components, which from all leading CAD software packages model size without compromising accu- Femap can do. But if you tried including Solid Edge® software, racy. For example, thin-walled structures to do that with something as SolidWorks, Autodesk, NX™ software, can be represented by fewer two-dimen- big as a [drilling rig] hull, your Pro/ENGINEER, CATIA and I-deas™ model would be composed of software.