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A case study of an application of shape optimization techniques in the design of an upper control arm of an automotive suspension system has been presented. An existing design of an upper control arm had high stresses and low fundamental frequency. The designer's inputs as to the various possible shape changes, constraints of movements etc. were built into the optimizer as shape variables and constraints. Shape optimization was then performed using approximate direct linearization method of MSC/NASTRAN software. A number of design directions were obtained. With a 24% weight penalty the first frequency was raised to 834 Hz. and brought closer to the target of 900Hz. and the stresses were also brought down by 30%.

The aim of this analysis is to study the effects of flexibility of the suspension components like upper control arm, lower control arm and knuckle on the suspension forces as experienced by a vehicle. An independent front suspension, which was being proposed for a vehicle, has been used for this analysis. A rigid body quasi-static analysis was first performed. Later a finite-element model of the suspension first with rigid elements and later with flexible elements was analyzed using non-linear large deflection and compared with the rigid body results. It is found that flexibility of the suspension components only have a local effect and not much of a global effect.

A fuel filter system essentially consists of a center tube, which is screwed on to a head and rests against a bowl. A thin circular plate, called end-cap, slides inside the bowl with spline teeth. The fuel filter material is inside the bowl and rests on the end-cap. When the bowl is tightened an input torque is transferred to the center tube and on to the head. It is required to estimate the stresses of the various components when a maximum tightening torque is applied to the bowl. A non-linear large deflection contact analysis of the fuel filter system needs to be performed. A number of contacts between the different deformable bodies, i.e. head and bowl, end-cap and center tube, etc. are resolved for equilibrium.

A comparative study of two different chassis frames when subjected to independent front and rear towing loads has been made. These frames have different structures and are made of two different non-linear materials. The applied towing loads subject the frame material to very high stresses (above the yield point). Hence a non-linear large deflection analysis needs to be performed to find out the resulting plastic deformation after the towing loads are removed. It has been observed that one of the frames is strong in the front while the other is strong in the rear. Abaqus, which is a non-linear finite element (FE) solver has been used to evaluate the two designs.

The application of optimization technique in the frequency domain, to move the frequencies outside certain range, is presented. An engine cradle under development had very high responses in 50 - 60 Hz. range. A modal analysis identified the cause as the mounting springs' natural frequencies. Optimization technique (direct linearization method) was applied to change the spring stiffnesses to move its natural frequencies outside the range of interest. Response plots at various salient locations on the engine cradle, before and after optimization, confirmed the analysis. The large response in the frequency domain was moved outside the 50 - 60 Hz. range.

A case study of an application of shape optimization techniques in the design of an upper control arm of an automotive suspension system has been presented. An existing design of an upper control arm was taken as a starting design point. The designer's inputs as to the various possible changes, constraints of movements etc. were built into the optimizer as shape variables and constraints. Shape optimization was then performed using approximate direct linearization method of MSC/Nastran software. A number of design directions were obtained. The weight of the upper control arm was reduced by 15% and at the same time the maximum stresses were also reduced by 29%.