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Nowadays the concept of Fast to Market is the general rule, followed by all car makers. Whatever is researched and developed must be passed on to the consumer, the sooner the better. This have leaded Testing Laboratories around the world to look for ways of reducing development and validation time of a product. This paper shows a methodology used to reduce the development and validation time of a product, in terms of fatigue test. In this work will be given emphasis on the math aspects and will be showed the results of a 6 channel body / suspension multi - axial test, performed with an Omega, a vehicle produced by General Motors do Brasil. The fatigue test purpose is to reproduce the real road conditions in a fast way, in order to evaluate the vehicle components durability, avoiding under or over dimensioning. There are two basic types of fatigue tests, depending on the assemblage method: Force Response or Frequency Response.

Great strikes have been made in the last recent years in understanding and in designing to prevent fatigue failures in automotive vehicle components and systems. Since then, General Motors do Brasil, has been putting a lot of effort in this endeavor. The main asset that allows GMB to work in this direction is its locally existing Laboratory and Proving Ground facilities, along with the need to provide an economical design through weight reduction within a safe, reliable and modern vehicle concept. The primary purpose of this paper is to present an overview of some techniques used in fatigue or durability testing of a passenger car. The relationship between force and acceleration tests will be discussed and a new technique, Multiple Rainflow, for test time reduction is presented.