Hello! What could be the causes of giving high result of ALLVD?

In a hammer shock analysis (MIL-STD_901D), tried with fully & reduced integrated(Hexa and Tetra) elements are used, none of vicosity parameters are activated (explicit and contact), no mass scaling, no damping properties in the material model etc. Hourglass control options are not activated. Tried to used C3D8I elements but it gives the same result.

I can't think of any cause to shoot up this viscosity dissipation energy plot (starts to shoot up at the time of impact).

Thank you!