Learning Forum

[shalva.esakia]

Hello, I am simulating the bullet impact on glass and laminated glass with PVB interlayer. The problem that I found is that when the bullet hits the target it prematurely deletes that mesh elements that are not even touched yet. It might be correct but considering the fact that I was not able to find the ballistic limit of the monolithic glass even at 50mm thickness against simple cone bullet with 400m/s velocity is concerning to me. The material model used for the glass is JH2 for tempered glass. I was wondering if in the analysis settings of Explicit Dynamics tool, it is correct to turn off erosion on material failure and only leave the erosion on geometric strain. This actually does not trigger the presumed premature deletion of the elements but the model now is very sensitive to the strain limit, giving me drastically different residual velocities for the bullet on different limits. Is it correct to pursue the callibration of the geometric strain limit value or is it waste of time? I feel like as the erosion on material failure is turned off the JH2 material model becomes undermined in calculation and the software is only focusing on strain limits. Is this correct? What other thing can be a problem that triggers this inconsistancy in my initial simulation when the material failure erosion is turned on? 
Thank you!