Practical Nondestructive Testing Research Articles

Compact sensitive instrument for direct ultrasonic visualization of defects

A simple ultrasonic imaging cell based on the confocal combination of a plano-concave lens and a concave spherical mirror is described. When used in conjunction with a stroboscopic schlieren visualization system, it has the main attributes of a practical nondestructive testing instrument: it is compact, relatively inexpensive, and simple to operate; its sensitivity is fair, resolution and fidelity are good; it has a fairly large field of view and a test piece can be readily scanned. The scope of its applicability is described and discussed.

The application of acoustic emission to fibre-reinforced composite materials

Applied to metallic materials, acoustic emission is rapidly gaining status as a practical non-destructive test tool. This has resulted from exhaustive research efforts to detect and identify such features as phase transformation, plastic deformation and crack growth. This review examines the ‘state of the art’ with regard to composite materials where fracture processes are generally more complex and interpretation is correspondingly more difficult.