Hi everyone:

     I hope to conduct a static analysis on the metal target plate that has been struck by a projectile, including but not limited to analyses of crack propagation and fatigue life. As is well known, residual stress caused by plastic strain has a significant impact on the analysis results. Among them, what I am concerned about is the stress field after the stress waves have been 'completely' dissipated.

     Firstly, I created a three-dimensional solid target plate and a projectile. In the explicit dynamic analysis, the C3D8R element was used for simulation, and the impact simulation results were obtained.

     Then, I considered using the HARDNING option to attach PEEQ to the target plate. However, considering that there would be elastic strain caused by residual plastic strain after the stress wave dissipated, this method was not feasible. Through simulation, it was also found that the simulation results using the HARDNING option were less accurate than those obtained by using only the deformed grid components.

     Then, I considered using the method of adding large Rayleigh damping to the material properties of the new model to rapidly dissipate the stress waves. The results of the impact simulation were attached to the new model through the initial state. There are two issues here: (1) How to determine that the residual stress field is correct? (2) In the impact simulation, there are fragments that have separated from the main body of the component but without unit deletion. This causes this fragment to also appear on the new model. Whether the components used in the new model are the original target plates or the mesh components imported after deleting unnecessary units. I do not want the fragments to affect the subsequent static analysis. How can this problem be solved?

     I also tried other methods, such as: (1) Importing the plastic strain field and letting the software calculate the residual stress field by itself. (2) Import the stress field and let the software balance the stress field by itself. However, all these methods have problems: (1) I don't know how to only import the plastic strain field and let the software calculate the residual stress field. (2) Importing the stress field results using the software is incorrect, even if the grid numbers are exactly the same.

     In summary, my objective is: (1) At the beginning of the static analysis, obtain the residual stress field of the target plate after it is struck without any stress waves. (2) It is capable of conducting simulation analysis only on the main body of the damaged target plate. 

     I really hope to receive your advice!

Impact simulation model	Impact simulation results
initial state - 1	initial state - result
initial state - 2