Combined Variation Modeling of Structural and Tuning Components for Vehicle Performance Assessment

During the vehicle development process, dimensional variation simulation modeling has been applied extensively to estimate the effects of build variation on the final product. Traditional variation simulation methods analyze the tolerance inputs of structural components, but do not account for any compliance effects due to stiffness variation in tuning components, such as bushings, springs, isolators, etc., since both product and process variation are simulated based on rigid-body assumptions. Vehicle performance objectives such as ride and handling (R&H) often involve these compliance metrics. The objective of this paper is to present a method to concurrently simulate the tolerance from the structural parts as well as the variability of compliance from the tuning components through an integration package. The combination of these two highly influential effects will allow for a more accurate prediction and assessment of vehicle performance. Vehicle alignment modeling is used as the case study in this paper to demonstrate this developed process because the variability of alignment is a key contributor that impacts handling performance. The benefit of coupling tolerance analysis and system compliance analysis is the ability to ultimately assess static and dynamic effects of component variability on the range of ride and handling performance experienced by the customer.