Multiaxial Fatigue Damage Parameters: Literature Overview. Traditional Stress-Based Models versus Stress-Based Critical Plane Approaches

摘要

The global reach within transportation industry seems to be towards ever lighterload carrying components e.g. by using higher strength weldable steels. Structural weight reduction and/or the increase in payload of on-road and off-road vehicles may increase the magnitude of operational stresses for a given set of operating and environmental conditions, resulting often in reduced margins of safety factors. Designers worldwide are currently employing fatigue design code approaches (fatigue damage parameters) that are mainly derived from unaxially loaded small scale laboratory samples. Recent, developments in laboratory fatigue tests using more realistic (multiaxial) loads often indicate that the design code-based fatigue damage parameters are unable to predict the increased fatigue damage caused by nonproportional multiaxial loads. Therefore, prior to reducing the factors of safety by increasing the magnitude of structural responses, the nature of operational loads (uniaxial vs. multiaxial) should be accounted for and suitable fatigue damage parameters should be developed and experimentally verified.