In the force output (bold) for the CSHEAR sample element below, what are the units of the SHEAR-XX quantities, is it lb/in or lb? Per page 897/913 in the NX Nastran quick reference guide, they seem to be lb. If they are in lb, then how to get the shear flow from these numbers in lb/in?
A shear panel is a two-dimensional structural element that resists the action of tangential forces applied to its edges, and the action of normal forces if effectiveness factors are used on the alternate form of the PSHEAR Bulk Data entry. The structural and nonstructural mass of the shear panel is lumped at the connected grid points. Details of the shear panel element are discussed in Section 3.0 of The MSC NASTRAN Theoretical Manual.
The element coordinate system for a shear panel is shown in Figure 8-67. The labels G1, G2, G3, and G4 refer to the order of the connected grid points on the CSHEAR entry. The element forces are output on request in either real or complex form.
Figure 8-67 Shear Panel Connection and Coordinate System (Ref. MSC Nastran Quick Reference Guide)
The positive directions for these forces are indicated in Figure 8-68. These forces consist of the forces applied to the element at the corners in the direction of the sides, kick forces at the corners in a direction normal to the plane formed by the two adjacent edges, and shear flows (force per unit length) along the four edges.
The shear stresses are calculated at the corners in skewed coordinates parallel to the exterior edges. The average of the four corner stresses and the maximum stress are output on request in either the real or complex form.
Figure 8-68 CSHEAR Shear Panel Corner Forces and Shear Flows (Ref. MSC Nastran Quick Reference Guide)
A margin of safety is also output when the stresses are real.