Study on fatigue reliability evaluation method of mechanical system with damage structure under variable amplitude load

Abstract

The parts of large-scale machinery equipment are mostly welded with each other. Welded structures with internal defects can be regarded as damage structures, which is much easier to suffer from fatigue damage under the action of variable amplitude loads. In this paper, the scale welding structure system - hydraulic support is taken as the object of study. Firstly, combining with the characteristics of its workload, it adopts a new angle: The probabilistic characteristics of the load history of hydraulic support are described and the reliability evaluation of the structure is carried out from 'macro' and 'micro'. Secondly, the equivalent cyclic loading with equivalent stress amplitude is equivalent to the equivalent cyclic loading by applying the damage equivalent mechanism. Based on this, the calculation of the total probability and the statistical average algorithm, the fatigue reliability model was built. It can objectively reflect the real failure, the correlation between the sites of injury.