Effect of Distributed Damping on the Dynamic Behavior of Flexible Chassis of Heavy Road Vehicle Under Standardized Random Road Responses

This paper evaluates the dynamics of a heavy road truck on different random road conditions, whereas the issue of beam flexibility is also being accompanied. Heavy vehicles like trucks and buses having a large structure to carry their load ride in all kinds of terrains, for thousands of miles without failing structure. Structure (chassis or frame) of the truck should be able to sustain all types of vibration (i.e., longitudinal, transverse and flexural). This study starts with developing an analytical model with consideration of the Rayleigh beam approach, where the rotary inertia of the beam has also been admitted. This work also considered internal damping of the chassis, which has been neglected in past studies specifically for flexural vibration. Further bond graph model of the flexible structure of a heavy road vehicle is developed, where this model is derived through modal expansion approach. The dynamic response of the structure is analyzed under various random road conditions at different vehicle speeds. These random models of the road are developed according to ISO 8608 standard, whereas four (H1-H4) kinds of road categories are considered. Results show the dynamic response of the chassis under a real road response so that parameters of the various parts of the structure can be evaluated, which further raises the ride comfort and road holding capability of the structure. Further, this work also examines the effect of structural damping or internal damping on the dynamics of the system.