Finite Element Results - Bending Moments
The bending moments and shear forces within an element are caused by the out-of-plane deformation of the element alone. The bending moments per unit width can be expressed as a moment triad Mx, My, Mxy.
where:
Mx and My denote the bending moments in the direction of the local x and y axes respectively.
Mxy denotes the torsional moment.
A positive moment denotes sagging.
The bending moment triad can be understood in terms of the moments acting across a line drawn on the shell.
Consider a cut in the shell along a line with unit normal n, and let the material on the same side of the line as the positive normal be removed.
The free edge of the shell that has been created by the cut along the line with normal n, can be maintained in equilibrium if a moment is applied to the free edge.
The moment that must be applied to a unit length of the line is given by:
where:
mx and my denote moment per unit length of line in the direction of the local x and y axes respectively.