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Contact Modeling
Posted Sep 9, 2010, 11:44 a.m. EDT 1 Reply
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Hi,
I am trying to find the penetration depth of the z stress field in a silicon substrate when a Silicon probe of 10nm radius of curvature presses against the substrate with a predefined force in the nN range (defined as a boundary load on the probe). My solution in the attached model does not converge. I am using a 2D axisymmetric model (Structural Mechanics Module with contact pairs on the boundary) and I am increasing force applied at the top boundary of the probe tip as a the parameter. I am a new user so any help will be very useful.
Really appreciate your help.
Best,
Shraddha
I am trying to find the penetration depth of the z stress field in a silicon substrate when a Silicon probe of 10nm radius of curvature presses against the substrate with a predefined force in the nN range (defined as a boundary load on the probe). My solution in the attached model does not converge. I am using a 2D axisymmetric model (Structural Mechanics Module with contact pairs on the boundary) and I am increasing force applied at the top boundary of the probe tip as a the parameter. I am a new user so any help will be very useful.
Really appreciate your help.
Best,
Shraddha
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1 Reply Last Post Sep 11, 2010, 9:27 a.m. EDT
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Posted:
1 decade ago
Hi
I'm not sure its enough, but one thing I would do is not to us such large contact pair lines, but limit them to a smaller region. You can do this by splitting your 1/4 circle with a line i.e. at 30°, and splitting the horizontal edge in two at half the radius.
This eases the computation of the gap distances etc, in your case the normal of the spherical part is horizontal for any point on the top border, hence paralle to the supposed contact surface. THis is not ideal for the computational cvonvergence. But still it's probably not enough. You have "hard material wih relative small displacements, there could still be some scaling and numerical resolution issues.
Try to do a search on the forum, thee are several discussions about contact issues, and several usefull ones
--
Good luck
Ivar
I'm not sure its enough, but one thing I would do is not to us such large contact pair lines, but limit them to a smaller region. You can do this by splitting your 1/4 circle with a line i.e. at 30°, and splitting the horizontal edge in two at half the radius.
This eases the computation of the gap distances etc, in your case the normal of the spherical part is horizontal for any point on the top border, hence paralle to the supposed contact surface. THis is not ideal for the computational cvonvergence. But still it's probably not enough. You have "hard material wih relative small displacements, there could still be some scaling and numerical resolution issues.
Try to do a search on the forum, thee are several discussions about contact issues, and several usefull ones
--
Good luck
Ivar