Learning Forum

[jason xiao]

Hi guys. I'm performing a 2-step Workbench explicit dynamics analysis. In the first stage (0-5ms) I need frictionless contact and in second stage (5ms - 10ms)  change to breakable bonded contact. 

In a transient structural, it is possible to define with 'contact step control'.  I wonder how to achieve similar effect in WB explicit dynamics?

[Chris Quan]

It is possible to activate/deactivate boundary conditions in different load steps in Explicit Dynamics system. However, it is not possible to activate/deactivate contact regions or body interactions in different load steps in Explicit Dynamics system. 

If you have to use different type of contacts for the same contact/target of body/face pair, you may consider using WB LS-DYNA & LS-DYNA Restart Systems. You can use Frictionless contact at LS-DYNA system and then replace it with Breakable Bonded contact in LS-DYNA Restart system.

 

 

 

[jason xiao]

Could give me some hint because I'm not LS-DYNA user. What do you mean 'replace'? In LS-Dyna Restart I set restart type to 'full' because other wise I cannot define boundary condition 'remote displacement', which is the only way I found correct to define rotation with given rotating axis.

When I set supress/unsupress contact, the previous LS-DYNA schematic (E5) gets flush out and need resolve. 

When I go to environment -> conditions ->contact step control. It's greyed out.

When I select a bonded contact and go to LSDYNA pre ->contact property, only 'death time' is availble. What I need is birth time. While frictionless/frictional  contact has much more control than bonded contact.

My version is 2023R2. Hope I was operating something worng. Thank you.