Hello,everybody.

 Is there someone knows:

Where to find the cohesion value(COHE) of metal for the Friction Model of ANSYS contact analysis?

In ANSYS contact analysis, The Coulomb friction model defines an equivalent shear stress τ, at which sliding on the surface begins as a fraction of the contact pressure p (τ = µp + COHE, where  µ is the friction coefficient and COHE specifies the cohesion sliding resistance). Once the shear stress is exceeded, the two surfaces will slide relative to each other. This state is known as sliding. The sticking/sliding calculations determine when a point transitions from sticking to sliding or vice versa.

I have a question, for the same metal material, when will the elastic modulus will be changed? in another words, in what kind of processing or machine condition will the elastic modulus be changed? for example, to machine elements(gear, bearing ...), when the part surface is case hardened,will the elastic modulus be changed? if not, how can the difference of hardness between case hardened surface and without hardened substrate be reflected in FEM analysis? how can the case hardened surface parameters affect the contact stress when two part are brought to contact?

and a further question about this topic is will Carburizing and nitriding treatment change the elastic modulus of metals?

Thank you, for you help very much!