EVALUATION OF TRAILER CHASSIS STRUCTURE FOR INCREASED STIFFNESS

Abstract

The establishment of CPEC is likely to increase the road transportation in Pakistan by many folds, where heavy duty trucks will play vital role in carrying goods from Pakistan’s northern border to the Gawadar Port in south. The appropriate design of transportation vehicles will play a vital role in the life expectancy of these heavy duty trucks, which will be subjected to the tough conditions of Karakoram Mountain Range. Generally, heavy-duty trucks are designed to resist structure buckling with increased load carrying capacity. For this purpose, the truck beds are lowered to reduce the torsional effects. The torsional effects on the vehicle chassis increase by many folds as the C.G. (Center of Gravity) of the pay load moves up beyond critical limit. For resisting these effects and to have an off-road capability, chassis frames are made from sandwiched multi-grade steel layers. The major structural member is usually the expensive grades of Ti precipitated steels such as B750L. The design of two-axle general purpose heavy duty chassis frame for 26 ton trucks and higher capacities need to be modified to best suit the loading conditions and applications in Pakistan. Finite element analysis of the multi-layered multi-grade chassis frame steel structure was carried out for the selected heavy duty truck chassis. The obtained results were analyzed and alternate materials were sought as per our application which can provide a cost effective solution. Modifications of the structural members were carried out in order to reduce weight from the overdesigned regions; also over stressed regions were reinforced. The design criteria of strength and stiffness were adopted. The results showed that the proposed trailer chassis structure for increased stiffness fulfills the design requirements. Maximum stresses and deformations for various cross-sectional chassis, which is derived in this work, is less than the conventional chassis.