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Void Equations for my Truss Problem
Posted Feb 5, 2017, 4:13 p.m. EST Structural Mechanics Version 5.1 1 Reply
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Hi,
I am brand new to COMSOL. I am following a guide for setting up a truss structure provided by my professor. I have the truss created, however I am getting an error upon solving it at one of the points where there exists a point load. This truss is holding up a basket, attached to where the point loads are. We are only to model it as I have shown in the attached file. Any help as to how I can eliminate this error?
I am brand new to COMSOL. I am following a guide for setting up a truss structure provided by my professor. I have the truss created, however I am getting an error upon solving it at one of the points where there exists a point load. This truss is holding up a basket, attached to where the point loads are. We are only to model it as I have shown in the attached file. Any help as to how I can eliminate this error?
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1 Reply Last Post Feb 6, 2017, 8:21 a.m. EST
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Posted:
8 years ago
Hello David,
The problem is that the vertical truss on the right has nothing to keep it from rotating freely about its top point (In other words, there is no stiffness to resist a horizontal force applied to its bottommost point), and as a result the stiffness matrix for the whole structure is singular.
With that said, all the rightmost truss does anyways is transfer the load from its bottommost point to its topmost point, so you can remove the truss in question and just apply the load to its topmost point.
Best,
Jeff
The problem is that the vertical truss on the right has nothing to keep it from rotating freely about its top point (In other words, there is no stiffness to resist a horizontal force applied to its bottommost point), and as a result the stiffness matrix for the whole structure is singular.
With that said, all the rightmost truss does anyways is transfer the load from its bottommost point to its topmost point, so you can remove the truss in question and just apply the load to its topmost point.
Best,
Jeff