Heavy and Medium Duty Vehicle Suspension-Related Performance Issues and Effective Analytical Models for System Design Guide

The uniqueness and challenge of heavy and medium duty vehicle manufacturing is that the vehicle&s subsystems and major components are procured from different suppliers. As a consequence, engineering task coordination for total vehicle performance optimization is required even if the intended design modification is only on one component. In the case of suspension design, related subsystems such as the drive axle, driveline, brake system, steering system, and engine mounts should all be included for review. The related potential problems for study fall into three categories, namely: function, durability, and NVH. The effective approach in addressing all these issues early in the design stage is through computer modeling and dynamic system simulation of the suspension system and related subsystems. Reviewed in this paper are six models that have been successfully developed and used for problem solving and design guide: 1) brake chatter model; 2) ride comfort study of vehicles with solid axle suspensions and independent suspensions; 3) trailer axle roll-steer performance model; 4) steering system vibration model; 5) suspension articulation and deflection vs. U-joint angle model; and 6) a suspension component durability study. Discussions on each subject include the engineering background, the modeling requirements, and the problem solving methodology.