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How to calculate the average contact pressure of the actual contact area?

Posted 14.02.2019, 08:33 GMT-5 Structural & Acoustics, Results & Visualization, Structural Mechanics Version 5.3a 1 Reply

Kant Hegele
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Hello,

Im simulating currently contact pressure. For that i want to know the average contact pressure for every time step. I know that you can calculate the surface average, but my contact area is much smaller than the boundary surface. So is there a way to calculate the average contact pressure for the actual contact area?

thanks in advance.

Greetings, Kant

1 Reply Last Post 14.02.2019, 13:33 GMT-5
Henrik Sönnerlind COMSOL Employee

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Posted: 6 years ago 14.02.2019, 13:33 GMT-5

Hi Kant,

The integrated contact forces are already available as variables, so the only thing you need is the area in contact. If you integrate an expression which is 1 where there is contact and 0 elsewhere, you will find the area in contact.

The average contact force in the z-direction can thus for example be expressed as solid.T_totz/(intop1(solid.Tn>0)+eps)

The 'eps' is added to avoid a zerodivide if there is no contact.

Instead of defining your own integration operator 'intop1', you can parasitize on the one used to define solid.T_totz, and write something like

solid.T_totz/(solid.cnt1.int(solid.Tn>0)+eps)

There are also variables for the total contact forces per contact pair, with names like solid.cnt1.T_totz_p1 .

Regards,
Henrik

-------------------
Henrik Sönnerlind
COMSOL
Hi Kant, The integrated contact forces are already available as variables, so the only thing you need is the area in contact. If you integrate an expression which is 1 where there is contact and 0 elsewhere, you will find the area in contact. The average contact force in the z-direction can thus for example be expressed as solid.T\_totz/(intop1(solid.Tn>0)+eps) The 'eps' is added to avoid a zerodivide if there is no contact. Instead of defining your own integration operator 'intop1', you can parasitize on the one used to define solid.T\_totz, and write something like solid.T\_totz/(solid.cnt1.int(solid.Tn>0)+eps) There are also variables for the total contact forces per contact pair, with names like solid.cnt1.T\_totz\_p1 . Regards, Henrik

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