Learning Forum

[Samir Kadam]

What is kinematic hardening and what is the different between kinematic and isotropic hardening in application?

[prajput]

Hi @skadam- Kinematic hardening is one of the hardening rules that describe the behavior of material after reaching yield surface. In the principal coordinate system, for kinematic hardening, the yield surface remains the same shape and size but merely translates in stress space.

[Ashish Khemka]

Hi @skadam, For isotropic hardening, the yield surface is symmetric about the stress axes, which means the yield strength in tension and compression are the same and they remain equal with the development of the yield surface. However, this is not true for most materials in reality. The yield strength in tension and compression grows differently. Usually, an increase in tensile yield strength occurs at the expense of compressive yield strength. We can this Bauschinger effect. Kinematic hardening takes Bauschinger effect in account. 

[prajput]

Just to add: It should be noted that when the loading is monotonic, materials with isotropic hardening and kinematic will behave the same. Only when unloading is involved, the difference between the two hardening rules will be reflected.