Methodology for evaluating vehicle fatigue life and durability

Vehicle durability, which defines the useful life of a vehicle, is a high priority for some consumers. Life consumption monitoring can be used to determine fatigue damage by directly or indirectly monitoring the loads placed on critical vehicle components that are susceptible to failure from fatigue damage. By monitoring vehicle life consumption, the Army can predict mechanical failures before they occur and determine the useful life of vehicles. The example vehicle used for this study is the Ml 101 High Mobility Trailer (HMT) that is normally towed behind a High Mobility Multi-purpose Wheeled Vehicle (HMMWV). As originally designed, the HMT experiences a fatigue failure of the drawbar. For this analysis, experimental data was taken from a HMT traveling over known test courses. The data was used to validate a computer simulation, and to determine the feasibility of life consumption monitoring. Multivariate regressions and principal component analysis (PCA) were used to determine which sensors most accurately reflect the loads on the drawbar at' the failure point. Regression and dynamic models were made after the proper decimation and filtering of the data was determined. The models were then used to predict the fatigue life of the trailer. The results of this study show that simulations can be modified to be representative of the vehicle being tested. The results also show that the fatigue life and durability of the vehicle can be predicted with a model and data from sensors placed on the vehicle.