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Clapping

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Hi,

I would like to implement the clapping effect of a delamination (suppose in 2D). The sample is a rectangular composite. At the top side of the sample a continuous sine wave is excited. Inside the sample a delamination is included (see attached figure).

The problem in this simulation is how to implement the boundary conditions at the delamination. The delamination can either be opened or closed. Therefore I need a boundary condition which varies in time.
If a certain stress value on the delaminatino boundary is exceeded, the delamination opens. In that case their is a gap between the two faces of the delamination and at both faces stress-free boundary conditions has to be assumed.
In the case the two faces of the delamination tend to overlap the delamination is closed and continuity between the two faces is assumed.

Note that it should also be possible that the delamination is open at some points and closed at other points.

Is there someone who can help me with this problem?


2 Replies Last Post 02.03.2010, 07:44 GMT-5
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

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Posted: 1 decade ago 02.03.2010, 07:19 GMT-5
Hi

My approach, from what you tell, would be to make the delamination region as a thin "void" region, with a non linear stiffness, such that if the pulling forces exceeds a certain value the stiffness decreases sufficiently to allow the region to expand. You also need ALE meshing to allow this change in volume.

From my knowldge COMSOL does not have empty (void) contact elements.

Another way would to consider two rectangles with a common boundary in "assembly" mode and put the physics in the up/down boundary continuity link, with a non linear function that allows for separation of the boundary if the local forces exceeds some value

Hope this helps on the way

Good luck
Ivar
Hi My approach, from what you tell, would be to make the delamination region as a thin "void" region, with a non linear stiffness, such that if the pulling forces exceeds a certain value the stiffness decreases sufficiently to allow the region to expand. You also need ALE meshing to allow this change in volume. From my knowldge COMSOL does not have empty (void) contact elements. Another way would to consider two rectangles with a common boundary in "assembly" mode and put the physics in the up/down boundary continuity link, with a non linear function that allows for separation of the boundary if the local forces exceeds some value Hope this helps on the way Good luck Ivar

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Posted: 1 decade ago 02.03.2010, 07:44 GMT-5
Thanks Ivar for you quick response.

I also thought of using the "assembly" mode, but I don't see how I can enter the conditioned boundary condition into the program.
Thanks Ivar for you quick response. I also thought of using the "assembly" mode, but I don't see how I can enter the conditioned boundary condition into the program.

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