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Over the past decades, Computer Aided Engineering (CAE) based assessment of vehicle durability, NVH (Noise, Vibration and Harshness) and crash performance has become very essential in vehicle development and verification process. CAE activity is often organized as different groups based on the specific attributes (durability, NVH and crash). Main reasons for this are the expertise required and the difference in the finite element software technologies (explicit vs implicit) used to perform and interpret various CAE analyses in each of the attributes. This leads to individual attribute team creating its own model of the vehicle and there is not much exchange of the CAE models between the attribute teams. Different model requirements for each attribute make model sharing challenging. However, CAE analyses for all attributes start with common CAD and follow the same sub-process in vehicle development cycle.

For suspension systems, fatigue and strength simulations are accomplished mostly at the component level. However, the selection of loading conditions and replication of boundary conditions at the component level may be difficult. A system level simulation eliminates most of the discrepancy between component level and vehicle level environment yielding realistic results. Further advantage of system level simulation is that the boundary conditions are limited to suspension mounting points at body or frame and the loading is limited to wheel-end or tire patch loading. This provides for a robust set of boundary constraints that are known and repeatable, and loads that are simpler and of relatively higher accuracy. Here, the nonlinear transient dynamic behavior of a suspension system along with its frame and mounting was simulated using a multibody finite element analysis (FEA).

Two finite element methodologies for simulating oil-canning tests on closure assemblies are presented. Reflecting the experimental conditions, the simulation methodologies assume load-controlled situations. One methodology uses an implicit finite-element code, namely ABAQUS®, and the other uses an explicit code, LS-DYNA®. It is shown that load-displacement behavior predicted by both the implicit and explicit codes agree well with experimental observations of oil-canning in a hood assembly. The small residual dent depth predictions are in line with experimental observations. The method using the implicit code, however, yields lower residual dent depth than that using the explicit code. Because the absolute values of the residual dent depths are small in the cases examined, more work is needed, using examples involving larger residual dent depth, to clearly distinguish between the two procedures.

Build variation is an important aspect of vehicle assembly. However traditional variation analysis assumes parts are rigid, leading to overestimation of variations. A finite element analysis procedure to estimate the build variation due to variations of shape, size and mechanical properties of flexible parts is presented. In addition to the part deformation, assembly force and stress can also be calculated by this method. This procedure is illustrated with an example problem.