Non isotropic mesh size
Hello there,
I would like to know if it is possible to create non-isotropic meshes with gmsh. I know this is unorthodox at first glance because the mesh quality suffers, but I have two use cases where this could help me.
Firstly, I have a specimen that is being stretched. I know that the local strain in the notch will be very large, so much so that the calculation results will no longer give the correct result for large distortions. I would therefore like to "keep the distortion in advance", i.e. intentionally squeeze the elements in the notch area along the axis so that they have a good element quality under load.
On the other hand, I have components that are similar to this shaft. There are very small radii there, which have a high stress gradient. However, the stress state is relatively uniform along the circumference. If I would mesh such a notch radius isotropically, I would get too many elements to be able to calculate them. I would therefore like to create many subdivisions in the radial (magenta line) and normal direction (normal to the surface), but only a few along the circumference (yellow line).
This is normally not a problem with structured meshing, but since the components that I normally look at are much more complicated than these simple examples, I would like to know whether something like this would also be possible with automatically generated (therahedron) elements.