QP Update 6.74.32 Stability Improvements

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QP Update 6.74.32 Stability Improvements

Unread postby Sonideft » Tue Aug 09, 2022 7:52 am

This release continues with improvements to the structural analysis core of Quick Pole and focusses on pole stability/solvability.

Since all finite element programs use matrices of equations to solve for solutions, there are times when the matrices become singular or otherwise very ill-conditioned and can't be used. This is most common when a structure is near or past its stability limit. This creates zero (0.0) or negative values to represent structure stiffness in many key locations of the system matrix. This prevents an inverse of the matrix from being created, which is required.

Another case is where guy wires attached to struts go slack. Since guy wires are modeled as trusses, they need to be removed from the next analysis iteration loop or they will be assumed to generate compression forces, which is not accurate. Removing normal guy wires that go slack does not cause any issues in solvability. However, if they are attached to sidewalk struts, the struts and the guys need to be removed. This can be a problem as there are row/columns in the system matrix specifically for the strut's end point deflections. In this update, the system matrix is appropriately downsized so that slack guys and struts can be solved as well. Since these previously were handled differently, the analysis routine would have failed for numerical reasons and reported back to the designer that the pole was unstable.

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