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
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13. Section overview - Virtual Work and Calculating the Element Stiffness Matrix
Virtual Work and Calculating the Element Stiffness Matrix
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Summary

In this section, we'll cover the following:

  • Deriving the element stiffness matrix using the principle of virtual work for a plate element.
  • The theoretical origin of the stiffness matrix formulation.
  • Recapping and applying Gauss quadrature for numerical integration.
  • Implementing numerical integration to evaluate the stiffness matrix.
  • Developing a Python function to compute and store the element stiffness matrix for later use.

In this section, we explore where the element stiffness matrix equation comes from by applying the principle of virtual work to a plate element, filling an important gap in the theoretical development. We then shift towards practical implementation, introducing Gauss quadrature as the numerical integration method used to evaluate the stiffness matrix.

We then focus on showing how this integration process can be translated into code. By building a Python function to compute the element stiffness matrix, we create a reusable tool that will support the development of a full solver in the next section. By the end of this section, you will have both a solid theoretical grounding and a clear computational approach to calculating stiffness matrices for plate elements.

Next up

In the next lecture, we will work through the derivation in detail, seeing exactly how virtual work leads to the element stiffness matrix and equivalent nodal force vector.

Tags

virtual work principleGauss quadratureplate elementsstiffness matrix computationPython implementation

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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
14. How Virtual Works leads to the element equations