Mechanical model of fatigue damage mechanism and development process of hydraulic support

Hydraulic support is a key supporting structure in coal mine engineering, bearing complex loads. Existing studies mostly focus on single factors, such as mechanical load, stress distribution, or temperature change, ignoring their interaction. To comprehensively analyze the fatigue damage of hydraulic support, this paper designs a mechanical model based on multi-physics coupling, combined with finite element analysis, and systematically studies the fatigue damage mechanism and development process of the support under complex working conditions. First, multi-physics coupling analysis is carried out to establish the geometric model of the support, and the interaction between the thermal field, mechanical field, and corrosion field is combined to simulate the working state of the support under complex working conditions. The thermal-structural coupling analysis module is used in combination with the corrosion model to evaluate the influence of temperature change and environmental factors on the fatigue damage of the support. After that, the Morrow fatigue model is selected to calculate the damage accumulation in the loading cycle, and the crack propagation process is simulated in combination with the Paris law. Numerical simulations are carried out. Firstly, static and dynamic load analysis is carried out, and then, the cyclic loading is applied. The stress distribution of the support is calculated, and the stress concentration area and the location of fatigue damage are identified. Finally, the response surface method is used to optimize the model parameters, and the Monte Carlo simulation is used to perform uncertainty analysis to verify the model’s accuracy and reliability. Experiments show that the remaining life of hydraulic supports with different damage degrees can be successfully predicted, and the safety factor of hydraulic supports with support strength ranging from 0.8 Mpa to 1.6 Mpa is kept above 0.5.