In Finite Element Analysis, structures can be represented with a variety of elements including 0D, 1D, 2D and 3D elements. Thin structures in particular are commonly represented with 2D or surface elements.
Surface elements, also called two-dimensional (2D) elements, are used to represent a structure whose thickness is small compared to its other dimensions. Surface elements can model plates, which are flat, or shells, which have single curvature (e.g., cylinder) or double curvature (e.g., sphere). Surface elements can also be used to model sections that are uniform or non-uniform in thickness.
Below are various examples of thin structures and their respective midsurface representations. Click on the thumbnails for a closer look.
Midsurface Creation Process
A common way to produce a surface element mesh is to first create midsurface geometry that represent the midplanes of the thin walls and then mesh the midsurface geometry. For more details on the process, refer to 3 Steps to Create Midsurface Geometry.
Midsurface Creation for Beginners
The video below shows fundamental concepts that can get you started in your midsurface extraction, creation, and meshing process.