Tensile Yield Stress
The tensile yield stress for a material is the value of stress at which the material begins to deform plastically. It is also called the yield point and defines the transition from the elastic region to the plastic region.
If you define and run a static analysis with a linear isotropic material and if the value of stress in the material exceeds the value you defined for tensile yield stress then you should consider using an elastoplastic material in your model instead.
When defining an elastoplastic material you must specify a value greater than 0 for Tensile Yield Stress in the Material Limits layout of the Material Definition dialog box. This value along with the material constants specified for a hardening law are used to define an elastoplastic material.