Term Categories: Glossary

See shear wave

See Rayleigh wave.

Cracks formed on the surface of an object.

Any discontinuity which does not open onto the surface of the part in which it exists.

Force per unit area, often thought of as a force acting through a small area within a plane. It can be divided into components, perpendicular and parallel to the plane, called normal stress and shear stress, respectively. Usually expressed as pounds per square inch (psi), or megapascales (MPa).

A measure of relative change in the size or shape of a body. “Linear strain” is change (increase or decrease) in a linear dimension. Usually expressed in inches per inch (in. /in.), or millimeters per millimeter (mm/mm).

An ultrasonic wave traveling normal to the test surface.

The amplitude distribution of frequencies in a signal.

The cracking and flaking of particles out of a surface.

The distance between sources or transmitters and detectors or receivers on a testing device.