Comparison of vehicle durability testing methods

It is a common practice throughout the vehicle manufacturing industry to perform full-scale durability tests on new model vehicles. Durability tests are initially conducted on prototype vehicles for design validation and then later, on production units to ensure it's structural integrity and to obtain data that can be used for future design improvements. In the case of commercial and transit vehicles, this information can be particularly useful for projecting it's minimum expected service life. Vehicle durability testing typically involves subjecting the vehicle to stress inducing inputs similar to those that would normally be encountered in an expected service environment. These inputs are applied to the vehicle at an accelerated rate to reduce the total testing time. Vehicle inputs for a durability test are imparted through either a test track or a mechanical road simulators such as four-post shakers. Each method has its advantages and limitations. For example, road simulators provide input flexibility in exchange for increased setup and programming time; test tracks allow the testing of several vehicles simultaneously without the benefit of a controlled laboratory environment. Both methods offer the advantage of accelerated life testing. However, in the opinion of the authors, the advantages and disadvantages of these two methods are not clearly articulated in the published literature. This paper compares and contrasts these two methods of durability testing. Some of the basis of comparison includes: cost, maintenance, realism, time, flexibility to handle a variety of vehicles, measurement of inputs' effect, location of input, etc.