Past

The principal methods used in early forensic engineering included:

• the careful analysis of the service record of the component
• the review of the loads carried
• record of temperatures suffered
• analysis of the microstructure of the material used
• assessment of witness evidence.

This was usually carried out by optical microscopy, X-ray diffraction and chemical analysis.

Present

All of these are still required but the task of the forensic engineer has been aided by the introduction of certain key concepts and methods including:

Fracture mechanics - the analysis of loads applied to bodies containing cracks
Scanning electron microscopes - fracture surfaces can be analysed at magnifications of thousands to determine modes of failure, as well as the chemical composition of key components of the microstructure
Finite element analysis - the determination by numerical mathematics of stresses, temperatures at all positions within a body, rather than the analytical solution of simplified shapes
Computational fluid dynamics - this uses numerical mathematics to determine effects of fluids (gases or solids) on components or structures
Impact dynamics - the use of numerical and analytical codes and models to determine the behaviour of structures when hit by fast-moving projectiles.