FEA: How to create an FE Mesh model

Hello Everyone,

FEA Process is mainly divided into three step

1. Preprocessing

2. Processing

3. Post processing

1. Pre-Processing includes the following steps:- Preprocessing which is Normally called as Finite element modeling, which is the physical problem which is will be Modelled to Solve using Finite Element Method.

Pre Processing includes the following steps

• Model Designing
• Discretization or Meshing
• Selection of elements (1D, 2D, 3D )
• Geometrical properties (Thickness, Area, Diameter, )
• Material selection
• Constraints or Boundary conditions
• Loads
• Type of analysis

2. Processing or solution:-There are two general direct approaches used in the ?nite element method as applied to structural mechanics problems to get Solution. i.e.

1. Force or ?exibility method:-Internal forces as the unknowns of the problem. To obtain the governing equations, ?rst the equilibrium equations are used. Then necessary Additional equations are found by introducing compatibility equations. The Result is a set of algebraic equations for determining the redundant or unknown forces.

2. Displacement or stiffness method:-Displacements of the nodes as the unknowns of the problem. For instance, compatibility conditions requiring that elements connected to a common node, along with a common edge, or on a common surface before loading remain connected at that node, edge, or surface after deformation takes place are initially satis?ed. Then the governing equations are expressed in terms of nodal displacements using the equations of equilibrium and an applicable law relating forces to displacements.

Most of the Finite element software programs uses the Displacement or stiffness method to solve the Problems.

During the solution phase, ?nite element software assembles the governing algebraic equations in matrix form and computes the unknown values of the primary ?eld variable(s).

The equation is

[k] [x] = [F] & [m]x^2 + [c]x^1 + [k]x = F[t]

k- Stiffness matrix from a material property and geometrical shape xx Results needs to be calculated (Unknown) F- Applied force m- Mass of system xX2 - Acceleration xX1- Velocity

The computed values are then used by back substitution to compute additional, derived variables.

• Reaction forces
• Element stresses
• Heat ?ow

As it is common for a ?nite element model to be represented by tens of thousands of equations, special solution techniques are used to reduce data storage requirements and computation time.

Post-Processing:- Evaluation of the solution results is referred to as post-processing. Postprocessor software contains sophisticated routines used for sorting, printing, and plotting selected results from a ?nite element solution.

Various operations in the post-processing

• Visualization of Deformed structure
• Displacements magnitude in three directions
• Nodal stress magnitude
• Element stress magnitude
• Check equilibrium
• Factor of safety
• Strain energy
• Natural frequency
• Amplitude
• Time history
• Thermal stress and strain
• Plot deformed the structural shape
• Animate dynamic model behavior
• Produce color-coded temperature plots

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