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Improving Analysis With Better Physical Fidelity

A Look At The Latest LMS Virtual.Lab

What's the latest in the LMS simulation environment? With the latest release of LMS Virtual.Lab, 4.b, LMS North America (Troy, MI; www.lmsintl.com) has migrated its previous-generation simulation applications—LMS Sysnoise (radiated noise analysis), LMS Dads (engine analysis), and LMS Falancs (fatigue analysis)—to LMS Virtual.Lab. It still covers the design simulation and analysis of mechanical systems. Various other changes help it better mimic our physical world.

 

One of the new modules involves morphing. Doesn't that have more to do with CAD than with FEA?

New designs are often slight variations of existing designs. As in 3D CAD, analysts need a finite element (FE) model. The LMS Morphing module saves analysts from creating and meshing a new FE model from scratch. An existing FE model can be iteratively changed, stretched, adapted and otherwise modified to a new or different design. This can all be done during the concept stage of a new design, when neither detailed nor complete CAD or FE models exist of the new design. The morphed FE model helps in assessing whether a "predesign" meets performance targets.

 

How incomplete can the "incomplete" FE model be?

That pretty much depends on how the FE model will be used and what type of detail, and level of detail, will be required for design analysis. The Morphing module is only a shortcut to an FE model. Alternatively, you could start with a blank sheet of paper.

 

How does the LMS Structural Analysis module fit in?

It creates an active, associative link between the simulation process in LMS Virtual.Lab and the linear and non-linear structural FE solvers from Abaqus, Ansys, Catia CAE (computer-aided engineering), and MSC.Nastran. This is interesting because Virtual.Lab is based on the Catia V5 development platform (Component Application Architecture, CAA) from Dassault Systèmes. Not surprisingly, Virtual.Lab fully integrates with the CAE tools from Dassault. Because of the Structural Analysis module, Virtual.Lab integrates with other established solvers. Users no longer have to jump through hoops to either deploy V5 or somehow integrate Virtual.Lab with their existing non-Dassault FE solvers.

 

What about "empty" structures, namely the interior of a car?

Virtual.Lab Acoustics can automatically create a cavity mesh from a structural mesh (full vehicle or trimmed body model) by filling holes, removing ribs, and so on. (This would be a HEXA-dominant FE mesh of the interior cavity.) The module can also create an exterior acoustic mesh by "wrapping" the structure with a frequency-dependent "rubber sheet." This sheet smoothes out small surface features while maintaining the acoustical sensitivity of the exterior. According to LMS, creating a good cavity mesh conventionally takes 10 to 15 days; with Virtual.Lab Acoustics, a couple of hours.

Once the cavity mesh is made, the module lets engineers analyze the effect of, say, orifice and shell noises caused by mechanical and acoustic loadings of lightweight components (such as mufflers). Engineers can also analyze the effect of tire noise using techniques such as FEM/BEM (finite/boundary element modeling), I-FEM, frequency, and time domain. Coupling this module with Structural Analysis, for example, lets engineers trace acoustic radiation from analysis back to the structural point at the root of the vibration, such as the engine.

 

What's available for moving parts?

LMS Virtual.Lab Motion for multibody dynamic simulation extends its modeling and simulation capabilities to four additional applications: full-vehicle, suspension, gear system, and track vehicle. Each module has its own model creation and simulation templates, post-processing tools, and visualization capabilities. For instance, the post-processing in the suspension module includes such characteristics as Ackerman angle, wheel camber, caster, and toe; for the full-vehicle module, post-processing functions include body roll, pitch, yaw angles and rates, and suspension-related characteristics. The modeling template in the gear-motion module lets users define the nominal layout of the gear train, the gear properties, and the shape of gear teeth.

 

What else is there in this latest revision of Virtual.Lab?

Well, the Durability module has dedicated configurations for MSC.Nastran and Ansys users. It also has new functions for seam weld fatigue life analysis: analyzing thin sheet structures and improved algorithms for analyzing welds that change the angle between sheets. Plus it has some new visualization features, including one to pinpoint failure locations.

 

Position of the product?

Bruno Massa, director of corporate marketing for LMS International: "What we've been doing is transferring some of the technologies from the physical testing world"—where LMS has its roots—"into virtual simulation. Now we're trying to move analysis, once detailed FE models become available, earlier into the development cycle."