Load and boundary conditions of dynamic crack propagation model of heavy load transmission gear

The dynamic continuous growth of fatigue crack is realized by resetting the crack length each time. In the numerical simulation study, the crack length value is consistent with the actual measured crack length value obtained in the test.

Because the numerical simulation object is the stress intensity factor at the crack tip, that is, the maximum difference of each stress intensity factor in the same cycle. The maximum difference of the stress intensity factor at the crack tip under two static loads is the content of the static analysis of the structure. The tensile stress load is loaded through the linear transition amplitude curve, and the maximum and minimum values of the load are the same as the experimental values.

The actual process of numerical simulation is to get the simulation results through the internalization of the interaction of various boundary conditions. For various simulation situations, the priority is the setting of boundary related conditions. The main ones are: symmetrical / antisymmetric / fixed support, displacement / rotation angle, velocity / angular velocity, acceleration / angular acceleration, displacement / velocity / acceleration of connecting unit, temperature, acoustic pressure, pore pressure, potential and mass concentration. The CT sample of this subject has symmetry. Considering the simulation efficiency, we can improve the efficiency by establishing a 1 / 2 model for simulation experiments. However, considering that the research problem may involve crack propagation along the product, a complete compact tensile specimen model is established for finite element simulation in order to be intuitive. The displacement direction of the loading hole is limited to the X direction, that is, the displacement is set in the X-Y plane and maintains a vertical relationship with the load direction.