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Two Point Bend Test - Solid Mechanics
Posted May 11, 2015, 7:23 a.m. EDT Modeling Tools & Definitions, Parameters, Variables, & Functions, Structural Mechanics Version 5.0 1 Reply
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Hi all,
I wish to analyse the stress in a piece of thin flexible glass during a two point bend test.
In my 2D model I define a thin rectangular geometry (50mm x 130um). The linear elastic material node is applied to the geometry.
To simulate bending of the substrate I apply a prescribed displacement to a point in the middle of the substrate. In this case I tell it to move in the positive y direction by 10mm. The displacement in the x direction is set to zero meaning lateral movement is not allowed for this point.
At the two ends points of the substrate I apply another prescribed displacement of y=0 and leave the x displacement unchecked. These points are thus constrained in the y direction and free to move in the x direction.
When I solve this setup I find the substrate stretches due to the displacement in the middle and the two endpoints do not move. This is not quite what I want as I want the ends of the substrate to move inwards as the sample is bending and the glass should not stretch.
I think what I need here is a boundary condition saying that the length of the boundaries must remain constant but I am not sure how to apply this.
Any help is greatly appreciated.
Best regards,
Adam.
I wish to analyse the stress in a piece of thin flexible glass during a two point bend test.
In my 2D model I define a thin rectangular geometry (50mm x 130um). The linear elastic material node is applied to the geometry.
To simulate bending of the substrate I apply a prescribed displacement to a point in the middle of the substrate. In this case I tell it to move in the positive y direction by 10mm. The displacement in the x direction is set to zero meaning lateral movement is not allowed for this point.
At the two ends points of the substrate I apply another prescribed displacement of y=0 and leave the x displacement unchecked. These points are thus constrained in the y direction and free to move in the x direction.
When I solve this setup I find the substrate stretches due to the displacement in the middle and the two endpoints do not move. This is not quite what I want as I want the ends of the substrate to move inwards as the sample is bending and the glass should not stretch.
I think what I need here is a boundary condition saying that the length of the boundaries must remain constant but I am not sure how to apply this.
Any help is greatly appreciated.
Best regards,
Adam.
1 Reply Last Post May 15, 2015, 2:14 p.m. EDT
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Posted:
10 years ago
But the length shouldn't remain constant due to Poisson's ratio.
The key thing here is that if the end-points are free surfaces than the normal component of the stress must be zero at the end-points.
added: for my own interest, could you attach the model? I'm trying to reproduce what you did for my own experience and can't do so.
The key thing here is that if the end-points are free surfaces than the normal component of the stress must be zero at the end-points.
added: for my own interest, could you attach the model? I'm trying to reproduce what you did for my own experience and can't do so.