As the name suggests composite materials are heterogenous, resulting from combinations of two or more distinct materials. In composite materials the combination of materials is at the macroscopic level, resulting in discrete interfaces separating the constituent elements. When we think of composite materials, polymer-based variants are usually the first to come to mind such as carbon fibre reinforced polymers or glass fibre composites. However, there are also naturally occurring composite materials such as wood. Another commonly used but often overlooked composite material is concrete. Composites need not be complicated, something as simple as papier-mâché, a common craft material, is also classed as a composite material.

The fourth industrial revolution or Industry 4.0 as it is also known, is rapidly transforming the way businesses operate. Even NDT hasn’t been able to escape the advances in automation, “Internet of Things”, artificial intelligence, sensor technology, big data and analytics. Industry 4.0 promises to revolutionise business models and outcomes, meaning that the NDT we see today will likely not be the same as the NDT we see in the next decade.

There may be more recent developments in devices and equipment for inspecting the condition of structures, but the most basic and oldest techniques can still be reliable.

Eddy current testing or electromagnetic testing is based on the science of electric current being induced in conductors when the magnetic field around them changes. This flow of eddy current with changing magnetic field finds application in locating and sizing minute cracks and defects existing on the surface, can estimate the thickness of coatings, and can assist in determine the material make up (i.e. alloy) a test element.

The ultrasonic thickness gauge is a portable device used for measuring the thickness of a piece of material from one side. The principle behind the working of the gauge is to use ultrasonic compression waves to measure the thickness. The material in question can be metallic and non-metallic, and it can account for coated elements, making it useful in a range of applications.