Hi everyone:
I am conducting a simulation of the remaining strength of a component after it has been struck by an impact, and I need to take into account the influence of residual stress.
As shown in Figure 1, since the impact simulation needs to be carried out in the explicit dynamic analysis, stress waves will be generated. However, I only need the residual stress caused by plastic strain.
(a) The stress field after the impact | (b) The equivalent plastic strain field after the impact |
Fig.1
Previously, I had asked a similar question and the answer I received was to use the initial state and viscous pressure. However, after my attempt, I found that before and after importing with the initial state, the stress field and displacement field were the same, but the total strain field and plastic strain field were not the same. As shown in Figure 2.
(a) The stress field after the impact | (b) The stress field after the import |
(c) Displacement field after impact | (d) Displacement field after import |
(e) The total strain field after the impact | (f) The total strain field after the import |
(g) The plastic strain field after the impact | (h) The plastic strain field after the import |
(i) The equivalent plastic strain field after the impact | (j) The equivalent plastic strain field after the import |
Fig.2
I think this might be because the initial state actually only imports stress and displacement. However, in the impact simulation, after the bullet penetrates, it will continue to calculate forward. At this time, the damaged area will experience rebound, resulting in the final displacement field not being the maximum displacement field. This causes the strain field obtained by the software when calculating strain after the import to not be the maximum strain field. Therefore, the plastic strain fields before and after the import are inconsistent.
Therefore, I would like to try a new method: extract the total strain field (LE) and the plastic strain field (PE) from the impact simulation, calculate the product of the difference between the total strain tensor and the plastic strain tensor and the stiffness matrix, and obtain the stress field at the current moment.
I have currently found a method for importing the plastic strain field, but I haven't found a way to import the total strain field. Moreover, I haven't developed an approach in Abaqus for calculating the stress field based on the imported strain field. On the other hand, I calculated the derived strain field through an external program and found that there was a certain error between the obtained stress field and the stress field calculated by the simulation software. The errors were relatively small for most elements, but there were also some elements with very large errors.
In conclusion, my question is:
1、Is it reasonable that the strain fields are different after importing the initial state?
2、Is my method for calculating residual stress correct or adequate?
3、How to import the total strain field and the plastic strain field into Abaqus?
4、How can Abaqus calculate the stress field based on the imported total strain field and plastic strain field?
