This report describes a substantial research project to determine procedures for assessing the road-friendliness of heavy vehicle suspension systems.
The initial aim was to develop a procedure for replicating the on-road dynamic wheel forces generated by a heavy vehicle suspension in the laboratory on a simple two-post servohydraulic shaker facility.
The first series of tests were undertaken on a test vehicle fitted with steel suspension. Dynamic wheel forces were measured during a set of road trials. These were followed by a set of shaker trials, which aimed to match the on-road suspension dynamics.
The vehicle was modified and fitted with air suspension and the testing repeated. With appropriate modifications to the shaker control software and the vehicle support rig a reliable and reasonably fast method for replicating the suspension dynamics in the laboratory was developed.
Additional shaker trials were undertaken on the loading vehicle from the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF).
Simple linear computer simulation models were developed and used to refine the testing procedure. In the first instance a tuned model was used to calculate the required shaker excitations directly from the road profiles. This eliminates the need for a road test to provide the input data for the shakers.
The second use of the linear models was to develop testing strategies that minimise the effect of other vehicle parameters on the suspension's response. In this way a vehicle independent suspension rating could be obtained.
The findings of this study were then combined with those of other researchers to present a set of recommendations for suspension assessment procedures.
Keywords: suspension assessment, road-friendliness, pavement wear, dynamic wheel loads