Search results for query: *

Hello everyone, I want to model the following case and I use LS-DYNA for my simulation: 1) Two cylinders made of shell elements have to be connected by the edges. They have the same diameter, but are made of different materials. I tried TIED_SURFACE_TO_SURFACE, but they seem not to be tied...

Hello everyone, does anyone have experience to define a failure strain, so that after reaching this strain the shell element is deleted from the calculation? I am using the material model MAT24 Piecewise_Linear_Plasticity in LS-DYNA wehere I can define a "strain to failure". But I am not sure...

Hey, thanks for your answers! Normaly negative volumes in foams are caused by massive compression. In my case the compression was not that big, so I have been looking for another reason and solved it by enlarging the mesh of the second soil. I think the problem was the contact between the two...

Hello everyone! I have a problem to simulate an impact onto soil ground (Material Model 5 Soild and Foam) with LS-Dyna, because I am getting negative volumes which lead to complex speed of sound in the material. My model consists of two layer of soil (Automatic_Surface_To_Surface) and an round...

Ah okay now I know what you mean. My true stress vs strain curve has no descending brach because it is only defined up to UTS.

What do u mean by that? I do not have a descending section in my true stresss/strain curve. Do you mean the engineering stress/strain curve?

Where did you get this information? I could not find it in the manuals. As far as I know LS-Dyna extrapolate only in that way, if there is no true stress for 0 strain defined. I will test it and define manually the horizontal line to see whether it is extrapolated or a perfect plastic material...

Hi rb1957, what excactly do you mean by your first statement? True stress is based on the actual area, thats why FEA need true stress vs true strain curves. Yes it does, it is the default. If I define the true stress vs true plastic strain curve up to a certain epsilon value, a perfect plastic...

Thank you for your replies! I will assume a perfect plastic behavior after the Su like you suggested. I have compared both approaches and the extrapolated curve led to worse results. I am not interested in material failure or necking, I am trying to model the crash behavior of a thin walled...

Hello everyone, Currently I am investigating the crush behavior of thin walled tubes. Therefore I am doing some analysis with ANSYS/LS-Dyna. I have a brief question concernen the Material Model 24 (Piecewise Linear Plasticity): First of all I have obtained a true stress vs. true strain curve...