Does anyone know the formula that ANSYS uses for its initial choice of surface-to-surface contact stiffness?  I know the program changes contact stiffness as a solution advances, but there's some choice made to start out with, and I don't remember the formula for calculating it.  I have a written documentation at the office (could be an old xansys post), but I'm working remotely all week, so I can't look in my file cabinet.  As I recall, it involved both the depth of the particular contact pair (calculated by ANSYS) and Young's modulus of the material on which the contact elements reside, but I don't remember whether there might be a nondimensional factor.

Anyone?

Robert Dillworth, PE
Principal Engineer
T.: +1 212 233 2737 x966
Robert.Dillworth@socotec.us
SOCOTEC Engineering, Inc
151 W 42nd Street, 24th Floor
New York
, NY 10036
www.socotec.us
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Hi Robert,

Here's an Email from 2008 by Rod Scholl.

-----Original Message-----
From: xansys-bounces@xansys.org [mailto:xansys-bounces@xansys.org] On Behalf Of Rod Scholl
Sent: Friday, September 19, 2008 9:08 AM
To: 'ANSYS User Discussion List'
Subject: Re: [Xansys] what value for FKN?

Jerome,

I guess I meant to do a focus blurb on this, but forgot:

Contact stiffness = FKN * E / (Thickness/20)

So its E divided by 1/20th the element depth.  Remember that the presense of plasticity reduces this by a factor of 100.

It doesn't depend on element area (which makes sense given the units of psi).

I have a test script used in this investigation: below

Rod Scholl
Specialist Engineer, Analysis
Phoenix Analysis & Design Technologies
612-605-6894
602-218-5391 (AZ Toll Free)
Rod.Scholl@padtinc.com
http://www.padtinc.com

Joseph T Metrisin
Structures Lead

Florida Turbine Technologies, Inc a KRATOS Company
1701 Military Tr. Suite 110 | Jupiter, FL 33458 USA
+1 (561) 427-6346 Office | +1 (772) 834-4156 Mobile
Joe.Metrisin@kratosdefense.com

We are hiring; Join the FTT Team in Jupiter, Florida
Visit our website: https://kratosdefense.com

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-----Original Message-----
From: Robert Dillworth via Xansys xansys-temp@list.xansys.org
Sent: Monday, July 15, 2024 1:57 PM
To: XANSYS Mailing List Home xansys-temp@list.xansys.org
Cc: Robert Dillworth Robert.Dillworth@socotec.us
Subject: [External] - [Xansys] ansys formula for initial surface-to-surface contact stiffness

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Does anyone know the formula that ANSYS uses for its initial choice of surface-to-surface contact stiffness?  I know the program changes contact stiffness as a solution advances, but there's some choice made to start out with, and I don't remember the formula for calculating it.  I have a written documentation at the office (could be an old xansys post), but I'm working remotely all week, so I can't look in my file cabinet.  As I recall, it involved both the depth of the particular contact pair (calculated by ANSYS) and Young's modulus of the material on which the contact elements reside, but I don't remember whether there might be a nondimensional factor.

Anyone?

Robert Dillworth, PE
Principal Engineer
T.: +1 212 233 2737 x966
Robert.Dillworth@socotec.us
SOCOTEC Engineering, Inc
151 W 42nd Street, 24th Floor
New York
, NY 10036
https://urldefense.com/v3/http://www.socotec.us;!!KM6X6ZXWXVtZMQ!aJiYxAmoUQSrh-BYBb7laYdvyh0jsZOJQb3ktV2NkRIuQGdDRGgY_FpNrbSver3fBDfqrzDBwxBDow_eGB47yHrGzQ$
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SOCOTEC cannot guarantee the integrity of this communication. As the Internet is not a guaranteed secure environment, SOCOTEC cannot ensure that an e-mail is not interfered with during transmission, as such will not be held responsible for any damage from e-mail transmission.