Measurement of Road Profile and Study it's Effect on Vehicle Durability and Ride

Road roughness induces dynamic loads on vehicles, which cause fatigue damage as a result. Design of vehicle for durability is one of the key steps during vehicle development process. Vehicle durability is verified on test tracks, on test rigs, or, increasingly, by computer simulations. Does the test represent real-life vehicle usage? How many times should a vehicle travel over the test tracks to verify the durability? How should input signals to test rigs be generated? For doing this kind of analysis, it is always required to measure the vehicle response parameters such as wheel forces, axle and chassis acceleration etc. These measurement based approaches have high cost and are time consuming. As these are vehicle dependent parameters, exercises need to be repeated on each type/class of vehicle. Hence it is needed to identify and measure the parameter which is vehicle independent. It is commonly accepted that the road profile is the principle excitation to the vehicle. Therefore studies of understanding of actual road roughness are necessary to answer the key questions concerning these verification procedures and prediction of vehicle durability. In this regard, a research project was undertaken at ARAI to develop a system to measure the vehicle independent road profiles and study the effect of road roughness on vehicle durability and ride. This paper discuss about the findings of this research project. Along with these, this paper also speaks about methodology for analytical road-load predictions.