FEA a Boon or Bane

Finite element analysis method (FEA) allows detailed visualization of where structures bend or twist and indicates the distribution of stresses and displacements.

Finite element analysis method (FEA) allows detailed visualization of where structures bend or twist and indicates the distribution of stresses and displacements. FEA software provides a wide range of simulation options for controlling the complexity of both modeling and analysis of a system. Similarly, the desired level of accuracy required and associated computational time requirements can be managed simultaneously to address most engineering applications.

FEA is the application of the finite element method (FEM) to practical problems. The finite element method is a mathematical procedure used to calculate approximate solutions to differential equations. The goal of this procedure is to transform the differential equations into a set of linear equations, which can then be solved by the computer in a routine manner.

Here is a general overview of the process:

1. The physical problem is well defined, with set physical laws to be applied, in the form of differential equations.
2. The geometry of the object to be analyzed is defined, with the space occupied by it called the ‘domain’ and the surface enclosing it called the ‘boundary’.
3. External influences, acting on the boundary or domain, are also well defined, such as forces, pressures, temperatures or heat sources. These are known as ‘boundary conditions.
4. The ‘initial conditions’ of the object are also well defined. These are the set of values of all internal variables at the first moment of the problem, for example, initial velocities, pre-stresses, or the initial temperature distribution.
5. The domain is then split into small basic shapes, known as ‘elements. The set of all elements is known as the ‘mesh’. Also, the points where neighbor elements meet are called ‘nodes. The size of the elements will determine the precision of the approximate solution, the smaller being the better. However, a higher number of elements used will increase the demand for computational resources such as memory and processor time.
6. Then, all equations and boundary conditions are ‘projected’ into the nodes, resulting in a finite—but often large—number of linear equations.
7. The linear equations are solved by the computer and the list of resulting variables for each node and elements are written to files.
8. The resulting data is used to make numerical analysis, visualizations and design decisions.

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Now comes the question of why we should be discussing the idea of BOON or BANE. The reason is that of late students tend to expect too much from an FEM program. Essentially a tool like FEA when embedded in a programming language with a decent pre and post processor helps to cut costs and comes handy in the design and engineering process. Nevertheless, things become quite difficult when the user chooses not to operate wisely. Not to operate wisely points out to:

1

Using absurd boundary conditions

2

Not taking the correct material data into account

3

Not worried about meshing and its significance

4

Publish results without a careful verification

5

Dumping the aspects of validation

FEA usage among students and researchers for the purpose of fast-tracking progress on the projects they undertake is on the rise but at times some take it to be rather a beautification exercise with colorful plots spread all over there work report. This is where we call it a bane.

It is fundamentally not the tool but the ill-informed or insensitive user who at the end of the day sometimes render a worthy FEA procedure to a miserable show of results which eventually lead to failure in practice.

CPDLR programs in FEA at Bangalore and Dehradun will take you through a journey which not only relates theory with industrial knowledge but also bring out best practices in your working procedures with FEA so that this knowledge always relates as a Boon to you and to the people for whom you work with.