Initial Stress Shell Application and HistVarCosine in LS-DYNA

[zxhurs]

Hello，

I have a question regarding the application of Initial Stress Shell in tensile testing:
Using LS-DYNA version 4.11, under Application > Plastics Analysis > Import Data from Moldex3D, I obtained a set of Initial Stress Shell data for short fiber-reinforced composite injection molding. When I used this Initial Stress Shell data for tensile simulation, the test section of the shell suddenly disappeared. However, when I ran the tensile simulation without adding the Initial Stress Shell, the process proceeded normally.

I am unsure whether it is inappropriate to directly add the Initial Stress Shell keyword for the simulation or if it was not correctly referenced.

I found some web pages related to history variables, but I couldn't determine what these six variables specifically represent. It seems that History Variable 1 corresponds to the tensor component a11​.
https://www.dynasupport.com/howtos/material/history-variables

Additionally, could you please explain the application of the d3plot file under Post > Vector > HistVarCosine, particularly regarding the directions? I couldn’t find relevant information and wasn’t able to figure it out myself.

[Reno Genest]

Hello,

Are the residual stresses that you import from Moldex3D in the correct unit system? Make sure you are using a consistent unit system:

https://lsdyna.ansys.com/consistent-units/

You will find more information about importing data from Moldex3D in LSPP at the end of *MAT_303 in the LS-DYNA Materials Manual.

Note that "the mapped data will be exported as material history state variables in the initial stress keyword cards *INITIAL_STRESS_SHELL or *INITIAL_STRESS_SOLID.".

 

Let me know how it goes.

 

Reno.

[Reno Genest]

Hello,

The Post > Vector > Hist. var. cosine is used to plot vectors of material direction using the material direction cosines stored in history variables for certain materials. You will find more information in the LS-DYNA User Manual Vol I: LS-DYNA Keyword Manual

Also, you can visualize material directions for composite material models as explained in the following LSPP presentation: Composite Capability in LS-PrePost.

 

Let me know how it goes.

 

Reno.