Learning Forum

[Joerg]

I am using MAT_079 HYSTERETIC_SOIL with a prescribed damping curve via LCD. The manual / messag file states: "LCD can only reduce the damping compared with Masing, and a monotonically increasing difference between Masing damping and non-Masing damping is expected. Actual damping will not follow LCD if these rules are not observed."

My question is, if these conditions are not met for some strain entries along the curve, does LS Dyna ignore the entire curve throughout the whole analysis, or does it only default to Masing damping once the rules are not satisfied ? Below is a screenshot from the messag file of my analysis. Does this mean in this case my prescribed LCD curve was used except for the first three and last two entries ? Or was default Masing damping used during the entire analysis ?

[Dennis Chen]

would you be open to simply testing this out with a single element study?  I don't have the answer but this seems to be something that can be tested. 

[Joerg]

ok, that's what I will have to do then. Thanks for getting back to me so quickly.

[Joerg]

 

FYI for those interested it seems the program does use the LCD curve. I ran analyses at three strain levels (low – mid – high) for the case with providing the LCD curve (LCD_R0) and without (Masing). Low stress looks the same (almost linear, likely from Masing), but at mid and high strain the loops are narrower when supplying the LCD curve.