Learning Forum

[mehdisaloo]

Hello,

I have modeled a timber panel in LS-DYNA using *MAT_WOOD. The analysis goes well until an out-of-range velocity error terminates the analysis. 

I set ERODE=1 and DTMIN=0.5 to get rid of negative volume. I am also using TSSFAC=0.67 and ELFORM=1 for my model. Regarding the hourglass control, I used type 4 with the hourglass coefficient 0.03. When I run the model with such settings, element erosion will happen due to negative volume as you can see in the following picture, however, an error termination occurs because of the out-of-range velocities of some nodes. I wonder what the reason for this error!

 

Thanks in advance for your kind attention.

I look forward to hearing from you.

Regards,

Mehdi

[Jim Day]

To lessen the likelihood of improper material input, try using the PINE or FIR option for *MAT_WOOD. Predetermined properties are used with these options. If you're not already using a double precision executable of LS-DYNA, please do so. If out-of-range velocities persist, write more frequent plot states to d3plot as you approach the time at which the instability occurs. By postprocessing these more tightly bunched states, the origin and evolution of the instability may become apparent. Plotting velocities vectors can be particularly enlightening.