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The purpose of this paper is to provide a comparison of multiaxial fatigue limit models and their correlation to experimental data. This paper investigates equivalent stress, critical plane and invariant-based multiaxial fatigue models. Several methods are investigated and compared based on ability to predict multiaxial fatigue limits from data published in literature. The equivalent stress based model developed by Lee, Tjhung and Jordan (LTJ), provides very accurate predictions of the fatigue limit under multiaxial loading due to its ability to account for non-proportional loading. This accuracy comes from the model constant which is calculated based on multiaxial fatigue data. This is the only model investigated that requires multiaxial fatigue testing to generate the model parameters. All other models rely on uniaxial test results.

It is the aim of this presentation to deal with an improved transfer matrix method for three dimensional vibration analysis of a reciprocating engine crankshaft system, so as to provide an efficient and convenient method for complex crankshaft system dynamic analysis. For different type of crankshafts, only the numbers and relative direction angles of the cylinders are required as input data besides the structural data. The theoretically predicted frequencies and mode shape agree well with the experimental results. In the case of dealt with a four-cylinder two-stroke small engine, five times exciting forces are of the most important which induce the crankshaft resonance. An effective and convenient general computer program for disign engineer to operate has been developed.