871x
003228
2019-06-27

Question

How is it possible to avoid singularities on membrane surfaces due to form-finding?


Answer:
Singular reactions are induced by inappropriate form-finding data on the membrane edges and an unfavorable FE mesh.

  1. If a cable with unfavorable form-finding settings (too much sag or too little force) is applied to a membrane edge, the membrane surface will contract abnormally in the form-finding process, resulting in a non-optimally arranged FE mesh with corresponding singular force reactions.



    In this case, the form-finding settings of the membrane and the boundary element must match each other.

  2. The form-finding process starts with the initial FE mesh arrangement. If this arrangement is already unfavorable and does not correspond to the required shape parameters, the force corresponding to the shape found is also affected negatively.



    In this case, it is necessary to adjust the basic geometry so that the initial mesh corresponds to all shape parameters.
The graphical display of the mesh quality before and after the form-finding can be activated in Display navigator.

Mesh Quality