FEA- What is Meshing & Connection

Hello Everyone,

Engineers and scientists use finite element analysis, also known as FEA to build these models. The use typically begins with a computer-aided design (CAD) model that represents the physical parts being simulated as well as knowledge of the material. This information enables the prediction of real-world behavior, often with very high levels of accuracy. Proper meshing plays a critical role during this process.

What is Meshing - Meshing is a Process of subdividing the structure to Finite Elements or The process of changing the Infinite number of points to Finite Number of nodes and elements. This process is also called as Discretization (Meshing)

Why Do We Carry Out Meshing? The basic idea of FEA is to make calculations at only limited (Finite) number of points and then interpolate the results for the entire domain (surface or volume). volume). Any continuous object has infinite degrees of freedom and it’s just not possible to solve a problem in this format. Finite Element Element Method reduces the degrees of freedom from infinite to finite with the help of discretization or meshing (nodes and elements).

Type of Meshing:- 1) Automatic Meshing 2) Manual Meshing ( Hypermesh and ANSA are dedicated preprocessors for Meshing purpose).

What is Node & Element? Nodes and Elements are the very backbones of Finite Element Analysis. In FEA, you divide your model into small pieces. Those are called Finite Elements (FE). Those Elements connect all characteristic points (called Nodes) that lie on their circumference. This “connection” is a set of equations called shape functions. Each FE has its own set of shape functions, that connect all of the Nodes of that Element). Adjacent Elements share common Nodes (the ones on the shared edge).

What is Element Types?

How to decide the element type?

Note:-

1D Element- RBE2 element (1 independent node & multiple dependent nodes) adds (infinite) stiffness to the structure, e.g- bolted Connection while RBE3 elements (1 dependent node & multiple independent nodes) "distribute forces" around the connected nodes, without adding any stiffness. e.g- represent the lumped mass of the body.

2D Meshing (Quad & Tria)- 1) Sheet Metal- Thickness same through the component (0.154 to 6.35 mm). 2) Plastic- Thickness varies through component but must be less than 5mm.

3D Mesh( Tetra & Hexa)- Thickness more than 5mm

Element Size- 1.Type of Analysis -Explicit - where time step is governed based on element size density and speed of sound & Implicit- element size may not be that much critical 2. Accuracy of result: As the element size decreases, it increases the number of Nodes and one can have good interpolation to increase the accuracy of the result, but at the same time it will come with a cost of CPU and time. Note- as per thumb rule, Element size depends on the smallest features of component.

Relation Between Meshing & FEA Results: Use a larger element to mesh the profile and run the Analysis to see the results. Go on decreasing the size of elements and run analysis and see how much the result values are changing.

Mesh Element Accuracy-The shape of Elements in FE Analysis must be distorted from their Ideal shapes when meshing the irregular or complex geometric shapes. The major types of degeneration are Aspect Ratio, Skewness, Jacobian Ratio, Warping Factor, Maximum Corner Angle, Orthogonal Quality, Parallel Deviation, Taper, Curvature distortion and mid-size node position, Tetra Collapse.

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