In this lecture, we will cover the following:

• Extracting bending moments and shear forces from quad elements using PyNite.
• Iterating through elements and their corner nodes in natural coordinates.
• Accumulating and averaging nodal values from multiple element contributions.
• Computing maximum absolute moment and shear values for comparison and plotting.
• Mapping nodal results onto structured 2D grids for visualisation.

In this lecture, we focus on extracting bending moments and shear forces from a finite element model by looping through each quadrilateral element and evaluating results at its four corner nodes. We take advantage of PyNite’s ability to return results directly at nodal locations, simplifying interpretation compared to sampling at Gauss points. As we iterate through elements and nodes, we build an accumulator to sum contributions of moments and shears at shared nodes, while also tracking counts so that we can compute averaged nodal values.

We then process these accumulated results to obtain representative values for each node and determine maximum absolute values for each response component. Finally, we remap the nodal data onto structured 2D grids by creating coordinate-based lookup tables and assigning values to the correct grid indices. This prepares the data for contour-based visualisation in the next lecture, ensuring that results are organised spatially and ready for clear graphical interpretation.

Next up

In the next lecture, we will visualise the PyNite moments and shear forces, bringing together all the post-processing techniques developed so far.