CAE Spreads and Integrates its Analyses

Computer-aided engineering (CAE), including computational fluid dynamics (CFD), non-linear analysis, fluid structure interactions (FSI), and other forms of finite element analysis (FEA), is a very theoretical, very complex, and very compute-intensive scientific endeavor. Both product development and manufacturing engineering rely on CAE to show how things will behave in natural conditions, in normal wear and tear, and under stress from forces caused by unexpected or unintentional events. Because CAE is so important, it’s constantly under development. New software packages come out for new analysis domains; existing packages broaden to include more solvers and multiple analysis domains; algorithms are tweaked to run faster; packages get easier to use; and, lately, solvers and software packages are combining under one virtual roof.

New and broader
Engineers typically want their designs to stand the test of time. Or to fail gracefully and safely. The latter is especially true in crushable structures, which absorb energy and protect people and cargo during a crash. In terms of “new,” CZone for Abaqus from the Simulia group of Dassault Systèmes is an add-on for the Abaqus/Explicit FEA software. CZone lets engineers simulate composite components and assemblies upon impact. Engineers can predict the crashworthiness of crush zones, namely at the point of impact (front) and the back-up structure. The add-on also determines other potential failures, such as composite delamination, fracture, and buckling. CZone results can lead to design changes in the placement, thickness, construction, and geometry of crush structures to maximize energy absorption.

In terms of “broader,” STAR-CCM+ from CD-adapco (Melville, NY; www.cd-adapco.com) is already a multi-disciplinary CAE/simulation package. The program includes finite volume solid stress modeling, automatically solves the physics of both fluid and solid domains simultaneously, simulates the movement of solid bodies and heat transfers, simulates extreme levels of rotation (such as lifeboats falling into water or shipping containers slamming into the ocean), and simulates laminar-turbulent transition (such as for designing turbomachinery). Version 4 includes new erosion modeling, improved combustion models, and the capability to simulate melting and solidification.

In general, perfect simulations of the real world is the goal in CAE. The latest release of Polyflow from Ansys, Inc. is another step toward that. Polyflow is for modeling viscoelastic materials, such as many plastics, glass, rubber, pastes, and dough. The latest version includes several new solvers and modeling features tailored for specific applications. Three new solvers (fully coupled, multifrontal, and iterative) let engineers run simulations faster and on much larger meshes than in previous versions of Polyflow. For glass applications, Polyflow now includes thermal stress relaxation and Narayanaswamy models.

Speedier simulations
High performance computing (HPC) is a computing environment powered by supercomputers and computer clusters. Applied to CAE and other advanced computation problems, and compared to conventional desktop computers, HPC-oriented programs let users work with larger data sets, run more simulations, perform more complex analysis, and solve problems in less time. Much of the recent impetus toward HPC comes from two directions. First, buying several multi-core computers (dual- and quad-core), the basis of a compute cluster, has gotten where it won’t break the bank. Second, Windows HPC Server from Microsoft Corp. This software is basically an operating system for combining 64-bit desktop computers into high-performance computing clusters. Users can submit and monitor jobs from HPC-oriented programs without having to learn yet another, and complex, user interface. HPC-oriented programs are specifically written for the parallel computing managed by Windows HPC Server.

For example. the CFdesign HPC Module from Blue Ridge Numerics (Charlottesville, VA; www.cfdesign.com) dramatically speeds up the simulations of complex flows and thermal transfers. Company officials claim that even an HPC cluster with two computers (8 cores) can speed up simulations 400%. For example, a transient pump simulation on a conventional computer setup might take 10 hours. In a mini-cluster setup, the simulation takes 2.5 hours. That mini-cluster could be as simple as two desktops running Windows Server 2008 HPC, one host channel adapter for each desktop, a cable connecting the adapters together, software drivers for network support, and a network manager.

Centralized simulation management
The business strategy of growing by acquisition produces a particular problem in the world of CAE and simulation. The analysis tools appeal to different domains, and each software package has its own user interface and data format. Data translations and transformations introduce errors and inefficiencies, which are compounded by analysts having to master the user interface of each software package and the fundamental complexity of CAE. To help simplify their CAE product lines, vendors are creating single, integrated environments for their software to work in.

For example, SimEnterprise from MSC.Software Corp. integrates simulation and analysis, providing what CIMdata (Ann Arbor, MI; www.cimdata.com) calls “enterprise simulation management.” Essentially, this allows the knowledge captured by the specialists to be shared by others in the organization who need it—people who may not be specialists. SimEnterprise does this through templates that, according to CIMdata, “represent the best practices for pre-processing data, selecting and setting up solvers, and post-processing analysis results as learned and recorded by a company’s simulation experts.” SimEnterprise also provides a backbone for accessing engineering analysis tools and solvers from MSC.Software and other suppliers. SimXpert from MSC.Software is a standalone, multidiscipline CAE system for dedicated analysts and a major component of SimEnterprise. The SimXpert interface consists of “workspaces” (including structures, motion, thermal, and explicit) to help the analyst set up an FEA application and interpret the results. The SimTemplate Studio lets SimXpert users capture, share, and reuse all stages of the simulation process, which helps promote consistency and corporate best practices.

Isight from Simulia takes a different approach. It is an add-on to the company’s Abaqus FEA software. Isight does a lot of things under the heading of “simulation lifecycle management,” Simulia’s slant on product lifecycle management (PLM). But unlike current PLM products, it takes a more active role in the decision making in setting up and running analysis projects and simulations, and then in analyzing the results. As a design optimization front-end, Isight has a collection of optimization techniques (such as approximations, Monte Carlo analysis, Six Sigma, and design of experiments) for simulating behavior in an FEA package (Abaqus or third party). Through Isight, analysts can submit multiple optimization jobs to multiprocessor computers. Because Isight is also a reporting tool, analysts can explore the results of thousands of design runs within a predetermined range of design options, and quickly determine design trade-offs based on real-world behaviors. Last, as with PLM, Isight captures operational experience that can be revisited by analysts, management, and partners for decision support.