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Robust design approaches can be applied to create designs that are insensitive to input variation so that they work almost all the time, regardless of manufacturing and operating conditions. In this paper, the performances of two automotive designs - a steering column and a deck lid system - are significantly improved by using the robust design approach through mathematical optimization. For each design, calculation of the performance indices, the formulation, and results of the optimization problem are presented.

Optimization techniques can be applied to synthesize the design of automotive systems and components to meet product requirements. In this paper, the performance of two automotive designs - a rear suspension system and a clip shape - was improved by using optimization techniques. For each design, calculation of the performance indices and the formulation of the optimization problem are discussed.

Build variation has long been recognized as one of the most important factors in vehicle performance. In this study an elastic assembly simulation program is used to guide a wheelhouse assembly process design to reduce build variation. Five (5) different clamping schemes are evaluated through the simulation program. From the five proposed process design choices, the best assembly process was identified, which results in reduced assembly variation and less tooling and manufacturing costs. Two different variation simulation approaches, one based on perturbation and the other based on Design of Experiments, were used to predict the assembly variation. Good agreement between the two approaches provided a validity check for the simulation tool.

A method is proposed for simulating the effects of dimensional variation from geometric dimensioning and tolerancing (GD&T) specifications. The method converts GD&T specifications into equivalent covariance matrices which are needed in the statistical simulation of random processes. Examples are given to show how the method can be implemented.

A mathematical model was developed for the analysis of a fuel filler door with a torsional spring. The model calculates performance indices such as opening and closing forces, kinetic energy during opening and closing and the maximum spring stress. The model was integrated with an optimization program. Two types of optimization problems were formulated: the traditional problem which does not include the effects of random design parameters, and the stochastic type optimization, which does. An example shows how the mathematical model, in conjunction with optimization techniques, can help determine fuel filler door designs.

A direct method is developed for designing a vehicle fuel filler door with torsional spring. The design parameters include the door's geometrical parameters and spring dimensions. The design requirements are based on the finger force curve during closing and opening, and the bending stress in the spring. An example is included to demonstrate the effectiveness of the new method.