Crash analysis of attenuator

  • Last Post 09 March 2018
  • Topic Is Solved
Venkatesh Arivazhagan posted this 08 March 2018

Hello everyone,

i'm getting the equivalent von-mises stress value as zero in explicit dynamic analysis. The material for the flexible attenuator is adiprene and i have kept the shear modulus value for adiprene as zero. The rigid body material is concrete non-linear. I have a doubt does the material adiprene have any issues  in afecting my analysis  or the mesh quality. If it is so means, somebody suggest me how to improve the mesh quality and bring the result close to the environment as possible.

The distance between the rigid element and the attenuator is 5mm

the velocity is 21000 mm/s in x axis

the end time which i have given is 0.001s

The no. of mesh elements are 15707

The minimum edge length is 2.5

The zip file is attached for the referencesmesh imagestress image

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peteroznewman posted this 09 March 2018

Elastic Modulus 2e10 Pa


Elastic Modulus 2e9 Pa


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  • Venkatesh Arivazhagan
peteroznewman posted this 08 March 2018

You need a non-zero Shear Modulus if you want to calculate stress. Otherwise, you are multiplying strain by zero to get zero.

You don't need any gap between the rigid surface and the attenuator. You are just wasting time getting the solver to move the parts into contact. Reposition the parts so they are just touching.

You would be much better off creating midsurface geometry to replace the solid model, then you can have a much better mesh and just assign the shell thickness. I have attached a Parasolid file that has midsurface geometry and a plate that is in contact.

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