Incompressibility and Bulk Stress for Viscoelasticity

Hi all,

I am performing compression on a viscoelastic material with relaxation only in shear and the bulk being nearly incompressible.

The relaxation times for shear are of the order of millisecons so shear stress is dissipated almost immediately at the end. But there are high stresses due to bulk part.

I am not able to understand what these stresses due to bulk mean physically? Many literature articles say that since shear stresses are relaxed immediately, the body is stress free at the end. But what about the high stresses from bulk? Does it cause something like a springback or so?

 Any suggestion/discussion is greatly appreciated!

Thanks!