Learning Forum

[Emperor]

Hello , 

I work a lot with contact problems in Ansys Workbench, and I would like to know how the frictional stress (in MPa) works with a frictional contact, is there a method to add the frictional stress or is it included in the frictional coefficient (a relation that links them maybe)?

thanks in advance

[1shan]

The frictional stress is the sum of stress components acting along the S and R directions (as shown in the below figure) and is a result of tendency of the two contacting surfaces to slide against each other. In a frictional contact the two contacting surfaces can carry shear stresses up to a certain magnitude across their interface before they start sliding relative to each other. The Coulomb friction model defines an equivalent shear stress¤ä, at which sliding on the surface begins as a fraction of the contact pressure p (¤ä =┬Áp + COHE, where┬Á 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. Apart from the coulomb friction model you could also define your own friction model. "Is there a method to add the frictional stress" - Frictional stress is an output you cant add it, however there is a provision to add the maximum contact friction with units of stress (TAUMAX). The bodies start sliding if the frictional stress exceeds this value irrespective of normal pressure.
Check section 5.9.5 of contact technology guide for more details - https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v194/ans_ctec/Hlp_ctec_realkey.html.

[Emperor]

thank you for your very clear answer