Finite element analysis (FEA) is a computer-based simulation technique that predicts how a product or component will respond to forces, heat, vibration or other physical conditions. In Design Technology, it functions as a virtual prototyping method, allowing designers to evaluate and improve a design before producing a physical prototype.
How FEA works
FEA follows a systematic process:
- A three-dimensional CAD model is divided into many small regions called finite elements. Together, these form a mesh, with elements connected at points called nodes.
- The designer assigns relevant material properties, such as Young's modulus, density and yield strength.
- Boundary conditions are applied. These define constraints, supports, forces, pressures or temperatures acting on the product.
- Software uses numerical calculations to approximate the response of each element.
- Results are displayed using numerical values and colour-coded plots, helping the designer identify critical areas.
| FEA output | What it indicates |
|---|---|
| Stress | Internal force per unit area within the material |
| Strain | Relative deformation caused by stress |
| Displacement | How far part of the model moves from its original position |
| Factor of safety | The margin between expected loading and material failure |
A designer can use these results to change geometry, material or dimensions. For example, material may be removed from a low-stress region to reduce mass, while a high-stress region may be reinforced. A finer mesh can improve result accuracy around complex or highly stressed areas, but it increases processing time.
A common misconception is that FEA proves that a product is safe. FEA only predicts behaviour based on the model, assumptions and input data; therefore, results should be validated through physical testing.
IB exam technique
For A2.2 Prototyping techniques, explain FEA as an iterative virtual prototyping tool. A strong response should link the mesh, material properties, boundary conditions and calculated outputs to design modification, while recognizing that simulation does not replace physical prototyping.