Fatigue assessment of metallic structures under variable amplitude loading

Paper i proceeding, 2019

Many types of mechanical structures (cars, air-planes, trains) and civil engineering structures (bridges, wind turbines, offshore structures) are subjected to random in-service loading. Normally the load effects in these structures are composed of different stress ranges and mean stresses which are within the elastic limit of the material. One main problem with fatigue assessment under variable amplitude loading is the performes of fatigue life regarding load sequence effects. In this study a model deals with the problem of fatigue life assessment under variable amplitude loading composed of differing stress ranges and mean stresses which are within the elastic limit of the material take into-account the load sequence effects is developed. Computing of the stress range and the mean stress, in specific time based on the preceding load histories, consider load sequence effects. Using Palmgren-Miner damage rule and the new computed stress range and mean stress lead to predict the fatigue life. An evaluation of the model using data of five diffrent metals availbe in the literature has been investigated. The results showed that the proposed model describes the effect of the load sequence in elastic loading well.