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The road damage caused by heavy trucks is accentuated by the dynamic loads excited by roughness in the road. Simulation models of trucks are used to predict dynamic wheel loads, but special models are required for tandem suspensions. Parameter values to characterize tandem suspension systems can be measured quasi-statically on a suspension measurement facility, but it is not known how well they fit dynamic models. The dynamic behavior of leaf-spring and air-spring tandem suspensions were measured on a hydraulic road simulator using remote parameter characterization techniques. The road simulator tests were duplicated with computer simulations of these suspensions based on quasi-static parameter measurements to compare dynamic load performance. In the case of the walking-beam suspension, simulated performance on the road was compared to experimental test data to evaluate the ability of the walking-beam model to predict dynamic load.

Metal matrix composite (MMC) engine components for high performance racing applications were produced using the PRIMEX™ pressureless metal infiltration process. Utilization of these composites resulted in significant weight reduction and performance benefits for each component. The metal matrix composites which were evaluated consisted of aluminum alloys reinforced with 45-65 volume percent of either aluminum oxide or silicon carbide particulates. The high volume fraction of reinforcing particles resulted in significant increases in yield strength, stiffness, and wear resistance, while a significant decrease in the coefficient of thermal expansion was achieved as compared with unreinforced aluminum alloys. The tested metal matrix composite components included valve spring retainers, fuel pump pushrods, and transmission brake valves.