sliding contact between saand bags and truck trailer

[Asis Pokhrel]

Hello Everyone,

 I am trying to model sand bags and truck bed contact in crash simulation. I used *CONTACT_SLIDING_ONLY to model the contact between sand bags and trailer bed. I selected segment set id to define contact surface between sand bag solid and trailer bed. I have attached the pictures below. The issue is that the solid section that i have used to define sand distorts in the simulation. I used *MAT-173_MOHR_COULOMB to define sand solid section ( bags). What can i do to model the relationship ? 

Can you please suggest me some 

[James Kennedy]

Dear Asis,

 

Something you might consider to overcome negative volume of the bags themselves?

 

In LS-DYNA, a layer of null shell elements is used over a solid geometry to avoid negative volume because shell elements are inherently positive volume elements. When a layer of null shell elements is placed over a solid geometry, it ensures that there are no negative volumes in the solid elements beneath them. This approach helps in avoiding issues related to negative volumes, which can cause numerical instability and inaccuracies in the simulation results. The null shell elements act as a protective layer, ensuring that the solid elements underneath maintain positive volume throughout the simulation.

 

Sandbag modelling suggestion?:

 

https://past.isma-isaac.be/downloads/isma2016/papers/isma2016_0800.pdf

 

Sincerely,

James M. Kennedy

KBS2 Inc.

March 24, 2019

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[James Kennedy]

Dear Asis, 

 

See if this model can possibly be of some help? 

 

Sturt, R., Cengiz, C., Huang, Y., Go, J., Bandara, S., and Pillai, A., “Modelling Liquefaction  

of Soils with LS-DYNA using a SANISAND-Based Material Model”, 13th European LS-DYNA 

Conference, Ulm, Germany, October, 2021. 

 

https://www.researchgate.net/publication/355155315_Modelling_liquefaction_of_soils_with_LS-DYNA_using_a_SANISAND-based_material_model 

 

Sincerely, 

James M. Kennedy 

KBS2 Inc. 

March 25, 2024

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