GPR/LM/ET

 

Ground Penetrating Radar (GPR)

This geophysical NDT method sends radar pulses through the surface of a material or subsurface structure, such as rock, ice, water or soil. The waves are reflected or refracted when they encounter a buried object or material boundary with different electromagnetic properties.

 

Laser Testing Methods (LM)

Laser testing falls into three categories including holographic testing, laser profilometry and laser stereography.

Holographic testing uses a laser to detect changes in the surface of the material which has been subjected to stress such as heat, pressure or vibration. The results are then compared to an undamaged reference sample to show defects.

Laser profilometry uses a high-speed rotating laser light source and miniature optics to detect corrosion, pitting, erosion and cracks by detecting changes in the surface via a 3D image generated from the surface topography.

Laser stereography uses laser light to create an image before the surface is stressed and a new image is created. These images are compared to one another to determine if any defects are present.

Electromagnetic Testing (ET)

This testing method uses an electric current or magnetic field which is passed through a conductive part. There are three types of electromagnetic testing, including eddy current testing, alternating current field measurement (ACFM) and remote field testing (RFT).

Eddy current testing uses an alternating current coil to induce an electromagnetic field into the test piece, alternating current field measurement and remote field testing both use a probe to introduce a magnetic field, with RFT generally used to test pipes.