Hello, everyone

        I am currently conducting a simulation analysis of crack propagation in a region that has undergone significant deformation. The material in question is aluminum alloy, a type of metal with high toughness. The content of the simulation includes the load threshold at which crack instability and expansion occur under a gradually increasing load, as well as the number of cycles corresponding to the occurrence of crack instability and expansion under a constant amplitude cyclic load. I expect to be able to compare the differences between plasticity-induced cracks and linear elasticity-induced cracks in this situation, but I encountered some problems during the simulation:

        1、In the simulation of quasi-static crack propagation, it is necessary to set material properties such as Maxps and Quads. What kind of relationship do these material properties have with the values obtained from experiments, such as JIC? Or do I need to adjust the material parameters so that the force-displacement curve obtained from the simulation is consistent with the one obtained from the experiment?

        2、In the fatigue crack propagation simulation, is the value calculated by the direct cyclic analysis step the change in the J integral within each cycle, rather than the equivalent stress intensity factor?

        3、If I want to define the crack propagation criterion using the UDMGINI subroutine, can I calculate the J integral?

        4、If I want to define the fatigue crack propagation criterion using the UMIXMODEFATIGUE subroutine, can I calculate the change in the J integral? (The user manual states that this subroutine will only transmit the maximum and minimum values of the strain energy release rate or the maximum and minimum values of the stress intensity factor.)