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Using a finite element approach, a technique for optimization of an exhaust system design was developed. This technique involved the creation of the parameterized model, implementation of the loading and finally the optimization of the model. In the creation of the finite element model, pipe elements were used. Parameters were assigned to the structure using coordinate relations between nodes, instead of the positions of the nodes in coordinate space. The model was then verified using modal analysis. A random vibration analysis was used as a loading criterion for the model, as well as static gravitational loading. The optimization of the design focused primarily on the shape characteristics of the structure and secondarily on each component thickness. Using only thickness parameters, a 15% reduction of the weight of the system was achieved, with an additional 2-3% decrease in weight possible through shape optimization.

Using finite element methods, an exhaust system's design can be optimized for weight and cost considerations. The optimization process involved the initial modeling of the system, the determination of an accurate loading system and the iterative analysis of trial designs. A static, gravitational loading was initially applied to the structure. A dynamic loading was then applied, using sinusoidal displacements at the exhaust system's support points. The optimizations resulting from the dynamic and static analyses yielded structures with 22% and 25% reductions in weight, respectively.

The new design for a diesel engine chassis mount bracket was fitted with strain gages and placed in a test vehicle instrumented with an on-board data acquisition system to find stress levels under actual service conditions. All experimental stresses were smaller than endurance limit of the part, so the bracket was predicted to have infinite life. In addition, a finite element model of the chassis mount bracket was optimized. The solution suggested removal of three portions of the bracket, reducing the weight by 13.49% and saving some manufacturing costs.

An expert system, XPRING, for design and selection of helical compression springs has been developed. The expert system was implemented in CLIPS, a rule-based, forward chaining pattern-matching expert system language. Success has been realized in designing the springs to meet the user's requirements. However, further development is needed for the problem of multiple constraint satisfaction.

This paper presents an application of the finite element technique to the solution of the dynamic behavior of an engine chassis mount bracket. The method is used for prediction and evaluation of the natural frequencies and mode shapes of the engine chassis mount brackets. The influence of the C-section edges, ribs, bolt holes and boundary constraints on the modes of an engine bracket are analyzed according to the requirements for an engine mount. Some suggestions for improving the dynamic behavior of the engine bracket are presented.

A new diesel engine mounting bracket, that was used as a part of a repowering package for one ton trucks, was analyzed under maximum static loading using a finite element model. Upon finding stresses above the yield strength of the material, alterations in the design were made to stiffen the bracket in the areas of high stresses, the maximum of which was at the dampener mounting hole. This new design added several dimples and bends to increase the stiffness of the entire bracket, especially in the dampener mounting area. The results of these design changes indicated a successful reduction of the stress in that critical area. The fatigue life was evaluated for the chassis mount, and was found to be acceptable for this retrofit condition.