Line elements can be found in a few forms within the software. Beam, bar, and pipe elements are classified as line elements. Also, within the same category, but not defined the same way, are springs, rods, and cable elements.
Bar Element Geometry
Beam Element Geometry
Elemental Geometry
The element x-direction is defined from grid point GA to grid point GB. In this software users do not pick the end points, but rather the curves. Users can visualize the element direction by right-clicking on Total Elements and selecting Display Line Element and then Direction.
The element y-direction is defined by the orientation of the cross-section. The element orientation can be visualized in the same fashion as the direction, only you must select Orientation instead.
The element z-direction is defined by the cross product of these two vectors. Note that the element zx plane defines plane 2 and element xy defines plane 1.
Formulation Options
Only linear beam and bar element options are available. Bar elements can only have the same cross-section at each end of the beam (at GA and GB). Beam elements can have different start and finish cross-sections. When using this option each intermediate element cross-section is interpolated from the start and end points on a selected curve. This allows for definition of tapered beam sections.
Both Bar and Beam elements use Timoshenko beam theory. The shear stiffness factors adjust the effective transverse shear cross-section area according to the Timoshenko beam theory. The default values for K1 and K2 are infinite; in other words, the transverse shear flexibilities are set to zero.
Degrees of Freedom
Both beam and bar elements support all six (6) degrees of freedom at their end points.
Element Output
Beam and bar elements output results for each element at their end points. This means that a different result can be at end A of the beam then at end B. Bending results are about planes 1 and 2. This is identified in the output vector title.