Reply To: Negative Volume Error

[jingyeqian]

The negative volume often occurs when some elements suffer large deformation.  To alleviate this problem, the common solutions are as follows:

 

1. Reduce the safety factor of the time step (i.e. TSSFAC, lower than 0.6, but if TSSFAC is too low, the accuracy may decrease), which could improve the stability of the calculation.

2. Increase the coefficient of the stiffness hourglass.

3. Check the material parameters. Using more proper parameters can effectively avoid incorrect dynamic behavior, both for the impact body and target.

4. The most simple but not the most appropriate method is to adjust the threshold of effective plastic strain in the keyword *MAT_ADD_EROSION. Thus the large-deformation elements will be deleted more early. NOTE THAT: The number of the threshold should be negative, the absolute value is the effective plastic strain of deletion.