Search Results

A numerical method for generating a blockloading profile from a rainflow histogram is described. Unlike previous techniques, this method produces a blockloading profile which, when rainflow-counted, yields a rainflow histogram identical to the original. When implemented with modern data acquisition and signal-processing techniques, this generation method provides a means of developing blockloading test profiles which are correlated with actual service data. This key benefit elevates existing simple testing systems as useful and productive tools despite the emrgence of more complex testing systems.

Simulation technology for use in full or partial vehicle testing was developed in the 1970s. It requires meticulous multiaxial control coupled with the playback of frequency compensated realtime data. Simulation testing provides a virtual reproduction of actual service data, typically within 2% accuracy of load amplitudes. Use of this technology in automotive development became widespread in the 1980s. Recent advances have made simulation practical even on the component level, complementing more traditional testing techniques including simple playback, block loading and constant amplitude mechanical testing. As simulation technology has spread through the ground vehicle industry, so has the use of fatigue technology as a tool for data evaluation. This paper discusses the role of fatigue analysis in simulation testing, as well as its use for integrating simulation with more conventional forms of durability testing frequently used for evaluation of individual components.

A major challenge facing the vehicle simulation test laboratory is correlating (and thereby validating) the simulated “test track” with the In-service environment. This simulation is key to the use of data for durability analysis from the integrated design and testing engineering process. Presented here is an approach to integrating road simulation test and fatigue life analysis that produces needed results for test, design and analysis engineers. The core of the analysis is a fatigue-based “rig-to-road” comparison for an on-highway vehicle using strain-time data acquired at fatigue sensitive locations. The cyclic and fatigue damaging content of the field and simulation profiles are compared quantitatively for purposes of validating the laboratory lest, and to illustrate a method of reporting this validation to design and analysis engineers.