# Introduction to Finite Element Analysis (FEA) and element types used in FEA

This article deals with the overview of Finite Element Analysis (FEA) and types of elements used during Finite Element Analysis (FEA). Common element types used are linear, quadratic, and cubic nature. The cubic element gives a better result than quadratic and linear. Again quadratic gives a better result than linear. ANSYS software uses these types of elements during FEA. Here an attempt is made to highlight the common element types used in ANSYS software.

## Introduction to Finite Element Analysis (FEA)

Finite Element Analysis uses numerical methods to solve complex problems in Mechanical as well as civil structural problems. It deals with finding out the deflections of structural members, stresses produced due to various loading coming from applications and finding the right size and shape as well as orientation to optimize the design of the structure.Finite Element Analysis(FEA) solves the problem by dividing the problem domain into a small number of parts/cells/elements and for each element, the governing equation of problem physics is applied. A final solution is then calculated at the end by summing up the effect/solution of each element of the problem domain. The solution means deflection, stress, and strain at the desired location or points in the domain.

In FEA, the solution largely depends on element types. Each element type has its characteristics.

## Basic types of elements used in Finite Element Analysis (FEA)

### 1D (Line element)

Mainly of three types -

- Linear (2 Noded per side) e.g. Beam, truss
- Quadratic (3 Noded per side) e.g. Beam
- Cubic (4 Noded per side) e.g. Beam

The accuracy of analysis directly depends on the type of element chosen in analysis inputs. Cubic elements give better analysis compared to the quadratic element and quadratic gives a better result than the linear element.

### 2D (Area element)

Mainly of three types-- Linear (2 Noded per side) e.g. Plane stress
- Quadratic (3 Noded per side) e.g. Plane strain
- Cubic (4 Noded per side) e.g. Plate and shell

### 3D (Volume element)

Mainly of two types- Linear
- Quadratic

## Common element types used in ANSYS

### Element type LINK1:

- It is a 2D spar element that supports tension and compression forces in the applicationLINK1 does not support bending force- related information, Hence by LINK1 only approximate analysis is possible
- This element has only two degrees of freedom (Displacement in X and Y direction only)
- Example: Truss elements can be analyzed by LINK1 element

### BEAM

2D elastic 3 elements:- This element supports compression, tension and bending capabilities during the analysis
- 2D elastic 3 element has three degrees of freedom (Displacement in X & Y and rotation about 2 axes)

This element defined by 2 nodes, cross-sectional area, the moment of inertia, the height and material property - Element height is used only in the bending and thermal stress calculations
- The Moment of inertia in the z-direction can be neglected if large deflections are not used.

### 3D beam element

Element name: Beam 4- This element supports uniaxial compression, tension, and bending capabilities.
- It has six degrees of freedom, three in displacement in X, Y, Z direction and the remaining six in rotation about the same X, Y, Z-axis.
- Inputs required to define completely this element are the cross-sectional area, the moment of inertia, the thickness along with all directions and shear and strain deflections.

### Element Type: Shell

Element name: Elastic 4 node 63- This element supports both membrane and bending capabilities.
- Both in-plane and normal loads are permitted for this element type in particular applications
- It has six degrees of freedom, three in displacement in X, Y, Z direction and remaining six in rotation about the same axis.

### Element Type: Solid/Brick

- Element name: Brick 8node 45
- This element is used to do Finite element analysis of 3D or solid objects

I am learning ANSYS APDL. I have a doubt in ANSYS A element type.