This option is used to specify additional properties for structure bars such as: truss bars (for which axial forces act), bars which can perform only in tension or compression, as well as bars for which the influence of shear forces on structure deformations is considered. Open the Advanced Properties dialog using either method:
- Click Geometrymenu > Additional Attributes> Advanced Bar Properties.
- Click
.
The following options are available in the dialog:
- Truss bars - Defines truss type bars in frame structures. Note that this definition does not let you assign releases to a frame element, but it changes the type of finite element from a beam to a truss.
Previously, using a truss bar in a frame structure required that you define bar releases. Using truss finite elements decreases the number of degrees of freedom in a structure model, which reduces the calculation time for large structures.
Note: You can only use the Truss bars option for structure types in which bar elements of a beam type are used. This means you cannot use this option in the following structures: 2D truss, 3D truss, plane stress structure, plane deformation structure, and axisymmetric structure. These structure types require that all bars be truss bars. - Consider Shear Forces in Deformation Calculations - When selected, the influence of shear forces on structure deformation is considered in the calculations for the specified bars. You must define the shear modulus for these bars.
- Tension/Compression Bars - When selected, bars will only transfer compressive or tensile forces during structure calculations based on whether Tension Bars or Compression Bars is selected.
When selected, 2 additional options:
Compression Bars and Tension Bars become available. The field at the bottom of the dialog, lets you define bars (graphically or by entering their numbers) as follows: truss bars, bars performing in tension or compression, or those bars for which the influence of shear forces is considered in the calculations of structure deformations.
Note: Currently, the calculations for tension and compression bars are performed the same way as for truss bars. Therefore, when selecting the Tension/Compression bars option, the Truss bars option is selected automatically.
When the Truss bars option is selected, pay attention to the attributes and loads assigned to the selected structure bar because of the difference in the work of a truss element with respect to a beam element. A self-weight load of truss bars is generated for bar element nodes. For loads applied along the length of a bar, only the loads applied along the bar's axis are considered, whereas, transversal loads are ignored. This rule pertains to the following load types:
- Uniform load on a bar
- Trapezoidal load on a bar
- Bar force.
The Inactive bars option is at the bottom of the dialog. When selected, the bars whose numbers are specified in the Bar list field or highlighted in the drawing area, are disregarded when the model is generated. (The bars are ignored when generating the finite element mesh).