Learning Forum

[David Scally]

I have designed a tubular chassis using a wireframe and assigned each line with a beam profile. The FEA for this works great but I now need to complete crash analysis on the chassis. I have used a velocity vector in the X direction on the main body of 15m/s, the wall is a rigid body and the results shown above are using the strain_1 in user defined results. However when the animation is played it shows that after the impact the beams do not plastically deform and behave elastically and 'jiggle' as the body effectively bounces off the wall. The material assigned is the AISI 4130 Steel provided in the ansys library and I struggling to figure out why I can't achieve plastic deformation in the beams without going for a 3D mesh.

Any help would be greatly appreciated.

[Armin]

Hi David,

Could you try the following items:

Define a plasticity model using one of the models available under Engineering Data like Bilinear Isotropic Hardening or Multilinear Isotropic Hardening using typical steel properties to see if you observe plastic deformation using a custom-made plasticity model.

Try refining the mesh in the beams. The element size appears too coarse and may not properly resolve plastic deformation.

[David Scally]

Hi Armin,

I have added a plasticity model using the data from another post on this forum so thank you for that. Would you have any idea how to keep the beams connected? I have connected them in space claim so they should count as joined no?

[Armin]

Hi David,

It appears that the ends of your beams are not sharing a node. Please check if this helps: Once you have created all the line bodies in SpaceClaim, highlight selected parts under the part tree, right-click and select Move to New Component. After specifying a cross-section for the line bodies (in the Prepare tab), go to the Workbench tab, and select the Share object. The nodes at the coincident regions should be merged (shared topology).

You can also try creating Bonded contact within Mechanical but you may try the approach above first.  

 

[David Scally]

You are an absolute god send, got it fully working now