ABAQUS/Explicit: Sudden jump in Total and Internal Energy 1

[ShadowWarrior]

I'm doing a drop impact simulation, everything looks fine when I use Elasto-Plastic material through VUMAT.

But there is sudden jump in Total and Internal energy when I use Elasto-Viscoplastic material model through VUMAT. Upon close inspection, it seems that the Total Strain Energy is having the jump, which in turn adds to Internal and later to Total Energy.

Anybody has any idea what is going on? I'm using Nortons' law to address strain-rate sensitivity.

 

[ShadowWarrior]

For future reference, the above problem occurred due to large time increment size, resulting in a very large Viscous Dissipation (ALLVD) that contributed to ALLIE and ETOTAL.

Choosing a smaller time increment or tinkering with mass scaling settings will rectify this.

 

[IceBreakerSours]

Thank you for posting the resolution.

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[ShadowWarrior]

A community is all about give and take.

The important lesson I learnt with this problem is to, output all energy variable in the initial trial runs during model build up and keep an eye on them for anomalies.