A CONCURRENT ENGINEERING DESIGN SYSTEM FOR POLYMERIC-BASED COMPOSITE AUTOMOTIVE COMPONENTS

The major aim of this research work was to develop a system for concurrent engineering of polymeric-based composites for automotive pedal box in the interest of reducing weight and cost. This system was designed in such a way that it enabled designers to identify the materials that satisfied a set of predefined design constraints in terms of weight and cost reductions. The system consists of integrated KBS, solid modelling system, materials database, and design analysis tool. The development of such system ensured the success of the polymeric-based composites for pedal box system in terms of reducing the number of parts, weight, processing and assembly time, and cost while improving the quality and design flexibility. Pedal box system is an automotive component which was very much overlooked by the driver and owner of the automobile, but it was very much a vital part of the automobile. The system developed chooses what materials to be used for four major components of pedal box system - the mounting bracket, accelerator, brake and clutch pedals. Few materials candidates from the class of aramid, glass and carbon fibre reinforced polymers were proposed to be used in the decision. These materials must satisfy a set of predefined criteria, specifications and constraints in terms of performance, costs and manufacturability. The materials, that satisfied all these requirements, were chosen as the candidates for the components. The knowledge-based system’s nile-based reasoning was used to accomplish this task. The selection process was carried out in two stages because after the first stage of selection, a number of material candidates were found to be suitable. Arrow’s impossibility theorem, one of the theory of multi-attribute selection problems was used to come up with the final material of a component. The materials selected for accelerator, brake and clutch pedal were glass fibre reinforced polyamide 66 and for mounting bracket was glass fibre reinforced PET. The design of pedal box system used total design methodology to come up with the best conceptual design. Various design methods had been used in the design process such as product design specification (PDS) , evaluation matrix and different types of idea generation techniques. In the detail design phase, the design was developed using the CAD solid model package, Pro/Engineer. The pedal lever profiles were of “I” cross section with a “V” ribbing pattern for strengthening the structure for all three pedals. Pedal elements were designed to be symmetrically mounted on a common vertical mounting bracket. A common shaft was used for brake and clutch pedals but the accelerator pedal had its own shaft in the sideway of the common mounting bracket. Radii were present wherever possible in order to increase the strength, as sharp corners incured high stress points which resulted in fatigue failure or cracking. Design analysis was performed using Algor software to validate and decide on some important aspects of the design. Stress analysis and displacement results were used to decide on the ribbing pattern of pedal levers. It was found out that “V” type ribbing pattern was more appropriate than other patterns. FEA was also used to validate the data of yield stress for cantilever beams used as constraint values in the KBS of material selection. The beams were assumed, to represent the pedal lever and the gusset, in the preliminary study of yield stress, used in the KBS of material selection. The results of FEA von Mises stresses from contour plots of pedals and bracket seemed to be lower than the assumed values of yield stresses and hence the data used were validated. The novel model for cost estimate for polymeric-based composite of pedal box system was developed to estimate various cost elements of pedal box system. The system enabled the designer not only to calculate the total manufacturing cost but also to see the break down of costs and they were demonstrated graphically in the system. The cost and weight reduction calculations were also performed using the KEE (Knowledge Engineering Environment) system. From this study, the weight and cost achieved were: • 49.5 % weight reduction and 86 % cost reduction for accelerator pedal • 46.7 % weight reduction and 82 % cost reduction for brake pedal • 61 % weight reduction and 84 % cost reduction for clutch pedal • 24.9 % weight reduction and 152 % cost increase for mounting bracket • 31 % total weight reduction and 61 % cost reduction for the assembly of composite pedal box system.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

De Montfort University

Year dc:date.issued

1998

Author dc:creator

• Sinon, Mohd Sapuan Salit

Licence

• https://dora.dmu.ac.uk/bitstreams/f174d0ec-cd0a-412c-9ac5-0d8aa6d35d01/download