How is the mesh on linear elements modified?
Question:How is the mesh on linear elements modified?
Advance Design provides the option to define a manual mesh on linear elements in order to save time both in modeling and computation.
Linear elements mesh: by selecting one or more linear elements and accessing the properties window, all the available options that can be modified are in the Mesh category.
|Automatic mesh option inactive||Automatic mesh option active|
This option is useful when some structural elements should not interact with each other if they are two planar/linear elements or one planar and one linear.
"Start" and "End" refers to the orientation of the local x-x axis (red axis), if the element is drawn from node i to node j then the local axis will be orientated positive from i (start) to j (end).
- Small elements at end - the length of the mesh will increase from the minimum size defined at Secondary size to the maximum value defined in the Size field in the negative direction of the x-x axis.
- Small elements at the center - the length of the mesh will increase from the minimum size defined at Secondary size to the maximum value defined in the Size field in both directions of the x-x axis starting from middle.
- Small elements at both ends - the length of the mesh will increase from the minimum size defined at Secondary size to the maximum value defined in the Size field in both directions of the x-x axis starting from the ends of the element.
In the following figure a mesh size of 1.00m and a secondary size of 0.20m are used:
These mesh options are useful when linear elements are in the same plane as the planar elements and the general or manual mesh options of the planar elements are overwritten. In the extreme zones (corners) of the planar elements concentration efforts can appear and through the modification of mesh options of the beams, by setting a refinement at both ends, a better integration of the results can be attained both on the beam and on the slab.
Sxx stresses on linear element at extremity "i"
The modification of the mesh size has a beneficial effect to the effective computation of the model. For example, by defining a smaller mesh size in some areas of the structure while keeping a larger mesh size in some less important areas the computation time can be reduced significantly (for more details please see FAQ: How can I reduce the amount of memory required by the calculation)
The difference between the linear element with the Extend into the wall option deactivated (upper) and with the option activated (lower) is depicted in the following figure.