In this lecture, we'll cover the following:

• Identifying restrained degrees of freedom for a simply supported slab mesh.
• Understanding node degrees of freedom (vertical displacement and rotations).
• Generating a unique list of perimeter (edge) nodes using indexing logic.
• Using sets to avoid duplicate node entries.
• Converting restrained nodes into global degree of freedom indices using a mask.

In this lecture, we focus on constructing a complete list of restrained degrees of freedom for a simply supported slab. We begin by recognising that each node has three degrees of freedom, but only the vertical displacement is restrained along the slab edges. To achieve this, we systematically identify all perimeter nodes using structured indexing based on the grid layout. By storing these nodes in a set, we ensure that duplicates are automatically excluded, simplifying the process.

Once we have the full set of restrained nodes, we convert this into a list of restrained global degrees of freedom. We do this by applying a restraint mask that specifies which degree of freedom is fixed, and by mapping local node information to global indices using a consistent numbering scheme. This step ensures that each restrained condition is correctly represented in the global system, setting up the foundation for subsequent analysis steps such as assembling load vectors.

Next up

Next, we will construct the global force vector by computing and assembling the self-weight contributions from each element.