Cable Geometry form

The Cable Geometry form is a drawing tool used to determine the length of a cable added to a model. Initially, supports are assumed to be fixed, and only gravity load is considered.

Cable Parameters

Within the Cable Geometry form is a Cable Parameters area where cable length is calculated. If cable length is greater than chord length (distance between joints), the cable will have relatively small initial tension. If the cable is shorter than chord length, significant initial tension will be introduced, and resultant tension will be dependent upon the applied loading and the flexibility of the structure. 

Please note that defining cable tension in the Cable Geometry form does not generate prestressing force.

Tension

Besides being influenced by cable geometry, tension may be generated in a cable through the application of gravity load, strain or temperature load, and target-force loading. A specific cable tension may only be assigned through target-force loading (when possible), which is an iterative process. 

Once cable geometry is defined, and loading conditions are applied through load cases, cable tension will adjust such that resultant tension provides for equilibrium within the deformed structural configuration.

Notes

• The Cable Geometry form is accessible through Edit > Edit Line > Edit Cable Geometry.

• Relative length is cable length divided by cable chord length, which is the line between its start and end points.

Figure 1  Cable Element, showing connectivity, local axes, dimensions, properties, and shape parameters