FINITE ELEMENT ANALYSIS OF SHELLS - EARLY ACCESS 
Section 4
Expanding to a full plate element solver
21. Section overview - Expanding to a full plate element solver
01:28 (Preview)
22. Procedurally generating a rectangular mesh
24:30
23. Defining plate constraints
11:08
24. Defining the self-weight force vector
10:35
25. Building the structure stiffness matrix
10:05
26. Solving the system and extracting reaction forces
28:13
27. Plotting the plate displacements
18:10
28. Building an evaluation grid for stress resultants
10:31
29. Calculating the moments and shears
22:00
30. Visualising the plate bending moments
14:13
31. Extracting shear forces
29:04
32. Visualising the plate shear forces
12:21
33. Adding strip and edge masking to the shear plot
26:04
34. Adding magnitude clipping to the shear plot
10:40
35. Building an interpolation utility function
09:53
20. Calculating the equivalent nodal force vector
Virtual Work and Calculating the Element Stiffness Matrix
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Summary

In this lecture, we'll cover the following:

  • How to compute the equivalent nodal force vector for distributed actions on plate elements.
  • Application of Gauss quadrature to numerically integrate distributed loads.
  • Construction of the shape function matrix and its role in load distribution.
  • Implementation of the equivalent force vector calculation in Python.
  • Validation using regular and irregular (quadrilateral) elements.

In this lecture, we walk through how to calculate the equivalent nodal force vector when distributed actions, such as surface loads, are applied to plate elements. We revisit the integral formulation and show how it is evaluated numerically using Gauss quadrature, incorporating weighting factors, shape functions, and the determinant of the Jacobian. We demonstrate how to construct the shape function matrix and use it to map distributed loads onto nodal forces.

We then implement this procedure in Python, first validating it on a simple rectangular element where the load distribution is uniform and predictable, and then applying it to a more general quadrilateral element where the distribution is non-uniform. Finally, we encapsulate the logic into a reusable function and integrate it into our growing utilities file. With this, we've assembled the key computational tools needed to move forward and build a full plate analysis solver in the next section.

Next up

Having developed the key element-level tools, the next section focuses on expanding these into a full multi-element plate solver.

Tags

equivalent nodal forceGauss quadratureshape functionsdistributed loadsplate elements

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Finite Element Analysis of Plate and Shell Structures: Part 1 - Plates

An analysis pipeline for thick and thin plate structures, a roadmap from theory to toolbox

After completing this course...

  • You will understand how Reissner-Mindlin theory enables us to accurately capture both thin and thick plate behaviour.
  • You will understand how to turn the fundamental mechanics of plate behaviour into a custom finite element solver written in Python.
  • You will have developed meshing workflows that utilise the powerful open-source meshing engine, GMSH.
  • In addition to using your own custom finite element code, you will be comfortable validating your results using OpenSeesPy and Pynite.
Next Lesson
21. Section overview - Expanding to a full plate element solver