Measuring and weight optimising procedure for the front axles of commercial vehicles

Abstract
The method of fatigue evaluation under operational conditions is a prerequisit to achieve optimal designs with respect to the weight of the structure considered. This will be demonstrated for a 6,5-ton-front axle beam of a heavy truck. A reduction in weight of 14% was achieved for this specific component. Criteria like driving behavior and braking performance, influenced by the global stiffness as well as the fatigue life under operational conditions, i.e. customer usage, were taken into account. Theoretical and experimental stress analysis were tools, which were incorporated into the optimization procedure, the latter primarily for the verification of load assumptions and determination of local stresses in service. For the design engineer an easy access is provided to fatigul life evaluation, i.e. the relation between fatigue damage and variable service stresses resulting from individual driving conditions. The methodology described can be fitted to other design problems as well.