Simulation of Tensile test coupon for large plastic deformation and stress triaxility correction

[bedyhope]

i am simulating tensile test coupon to get true stress-strain beyond necking through revers method or so called trail and error method using Abaqus. the problem am facing is that, when i run the simulation using standard solver the obtained force is very high compare to experimental one. however, when i use nonlinear geometry option (NLGEOM) in abaqus the the results seems good until the non-geometrical necking start where the global force will drop rapidly. i tried to solve this through necking effect correction but it does not work. any hint will be appreciated.

 

[mrgoldthorpe]

Perhaps you should incorporate *POROUS METAL PLASTICITY in order to simulate the softening due to micro-void development?

 

[bedyhope]

thank mrgoldthorpe

yes its an option that requires additional work to get model parameters for Gurson model. but the experimental load-displacement does not show any softening till the fracture point which correspond to localized necking. the weird thing here is that the load (from simulation) after elastic limit shoot a bit high compare to experimental results.