Summary of FEA 101 at COSSUG

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As promised, here is a summary of the FEA 101 session that Richard conducted at the COSSUG meeting in Westerville, OH this week:

The session involved a basic discussion of what the finite element method is, and why a user should opt for it. The fundamentals of finite elements were established as a process of breaking down a structure into smaller segments in order to capture its response to loading conditions. This breakdown relates to the process called meshing where the model now is made up of elements and nodes (corner points on elements). The roots of this process were traced back to the mathematics that governs stresses and strains.

eq11

Rearranging the terms,

eq21

In other words, it can be said that any structure behaves very similar to a spring mass system, where F is the external force, k is the stiffness of the structure (contributed by the material and the geometry), and x is the displacement response to the instigating force.

The above principles were extended to the displacements of the nodes created in the mesh, thus depicting the deflection of the structure to the applied loads. Once the resulting deflections are determined, the strains and subsequently the stresses are captured in the geometry.

The discussion moved on to understanding the different meshes that can be created inside Simulation, and how the nature of the geometry (solid structures v. sheetmetal v. weldments) dictates the type of mesh to be created. The topic of converged results crept into the picture here, and hence the topic of refining meshes progressively to study stress/energy norm convergence was brought up.

The different steps in setting up a finite element problem were discussed in good detail:

1. Definition of the study – determining the type of analysis to perform based on the desired results (static, non-linear, linear dynamics for stresses and deflection, thermal for temperature, frequency for resonant frequencies, etc.)

2. Material – determining the type of material to use, its underlying assumptions, and the required material properties for the type of study

3. Fixtures (Restraints) – specifying the locations in the geometry where the structure is constrained from freely moving

4. Connections (contacts/connectors) – locating areas of existing/potential contact and also connecting multiple bodies together with virtual fasteners

5. External Loads (forces/pressure etc.) – indicating regions where the load acts on the design, and the nature of the loads

6. Meshing, running the analysis and viewing the results

Finally, there was a good amount of time invested in understanding what SimulationXpress offers (the free FEA introductory tool inside every seat of SolidWorks), and what its limitations are.

The seminar ended on a summary of some neat tips and tricks shown at SOLIDWORKS World this year. The discussion on the limitations of SimulationXpress will form the basis of the first part of FEA 201 next week, which will help lead into the full-blown Simulation Portfolio.

I will post some key take-aways from the session in my next post!!