Laboratory Evaluation of Heavy Truck Dynamics: Are the Test Results Useful?

This paper provides an insight into some of the benefits of evaluating heavy truck dynamics in the laboratory. Recognizing that the vast majority of ride and engineering tests that are commonly conducted on heavy trucks occur in the field or on test tracks, the paper shows that there is much to be gained from dynamic testing of a truck in the laboratory under proper conditions. Of course, the main reasons for considering laboratory testing are that the tests can be conducted a) at much lower costs than field testing, and b) in a much more repeatable manner. The argument against laboratory tests has always been that they may not represent the true dynamic environment that a truck would experience in revenue service. Some of the issues related to properly setting up a truck in the laboratory such that the experiments can relatively accurately emulate what occurs in the field are presented. Issues such as dynamic loading, instrumentation, and dynamic excitation of the truck are discussed in detail. A laboratory test setup is used to collect dynamic data on a class 8 truck, and the results are analyzed in both frequency and time domains. The results show that the laboratory setup can accurately represent the dynamics of the truck, and provide for time and cost effective evaluation of new products or trouble shooting existing truck components.