Member Sections

Each member must have a section assigned to it.  The section properties include:

•A: axial section area

•Ay: shear area along the member local y direction

•Az: shear area along member the local z direction

•Izz:  moment of inertia about strong the local axis z

•Iyy:  moment of inertia about weak the local axis y

•J:  torsional moment of inertia

Ay and Az may be zero, in which case, the program ignores shear deformations of the element.  Mathematically speaking, the program interprets them as being infinite.  For rectangular sections, Ay = Az = 5/6A.  For solid circular sections, Ay = Az = 0.9A.  For thin-walled hollow circular sections, Ay = Az = 0.5A.  For wide flange sections, Ay = web area, Az = area of two flanges [Ref. 6].  To consider member shear deformation, you must choose the proper option from the command Analysis > Analysis Options. Shear deformation, when considered, applies to both element stiffness and local deflections.