Foam compression 1m/s , problem at 50% of deformation , foam go throught impactor

sebmeca

Hi !

I try to simulate a foam compression at a constant speed of 1 m/s. Before I have realised the same compression experimentally. In order to compare simulation and experimental.

I block every movement on bottom of foam and I imposed a constant velocity to impactor.

To go to approximatively 50% of strain there is no problem, simulation and experimental are the same.

But after Simulation disgress from experiemental.

I use brick elements of 1x0.5x0.5cm.

 

Anyone have an idea to solve this problem

 

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Simon Križnik

Hi,

 

the issue is because the interface 'impacteur vs foam' had dtmin=0.6 If the time step of a slave node in this contact becomes less than dtmin, the slave node is deleted from the contact and a warning message is printed in the output file. This dtmin value takes precedence over any model interface minimum time step entered in /DT/INTER/DEL. Because dtmin is quite high, a lot of nodes are deativated from the interface, therefore penetrating the plate.

 

 

The recommended solid property parameters for material law 70:

If there is hourglassing, use Isolid=17, however your model runs fine with the above.

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