1. Scope

1. Scope

1.1 This practice establishes procedures for matrix array ultrasonic testing (MAUT) of monolithic composites, composite sandwich constructions, and metallic test articles. These procedures can be used throughout the life cycle of a part during product and process design optimization, on line process control, post-manufacturing inspection, and in-service inspection.
1.2 In general, ultrasonic testing is a common volumetric method for detection of embedded or subsurface discontinuities. This practice includes general requirements and procedures which may be used for detecting flaws and for making a relative or approximate evaluation of the size of discontinuities and part anomalies. The types of flaws or discontinuities detected include delamination, foreign object debris, inclusions, disbond/un-bond, fiber debonding, porosity, voids, and corrosion.
1.3 Typical test articles include monolithic composite lay-ups such as uniaxial, cross ply and angle ply laminates, sandwich constructions, as well as forged, wrought and cast metallic parts. Two techniques can be considered based on accessibility of the inspection surface; namely, pulse echo inspection for one-sided access and through-transmission for two-sided access. As used in this practice, both require the use of a pulsed straight-beam ultrasonic longitudinal wave followed by observing indications of either the reflected (pulse-echo) or received (through transmission) wave.
1.4 This practice provides two ultrasonic test procedures. Each has its own merits and requirements for inspection and shall be selected as agreed upon in a contractual document.
1.4.1 Test Procedure A, Pulse Echo (non-contacting and contacting), is at a minimum a single transducer transmitting and receiving a longitudinal wave in the range of 0.5 to 20 MHz (see Fig. 1). This procedure requires access to only one side of the specimen. This procedure can be conducted by automated or manual means. Automated and manual test results may be imaged or recorded.
1.4.2 Test Procedure B, Through Transmission, is a combination of two transducers. One transmits a longitudinal wave
and the other receives the longitudinal wave in the range of 0.5 MHz to 20 MHz (see Fig. 2). This procedure requires access to
both sides of the specimen. This procedure is automated and the examination results are recorded.
1.5 Other contact methods such as a ngle-beam techniques using shear waves to characterize welds, or surface-beam techniques using Lamb waves to detect impact damage in composite panel structures are not covered.
1.6 This practice does not specify accept-reject criteria.
1.7 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.

Keywords

matrix array probes, delamination, disbond, corrosion, pulse echo, through-transmission

Rationale

E07.06 standards cover PAUT in detail, but there are no detailed standards for MAUT or matrix array probes to my knowledge. The techniques described are user friendly, for example, no focal laws are needed, and are applicable to inspection using longitudinal waves either in pulse echo or TTU mode. The procedures described in this standard have proven utility in the inspecting 1) monolithic polymer matrix composites for bulk defects, 2) metals for corrosion, 3) adhesive bonds in metals, composites, and sandwich constructions for evidence of interfacial defects, and 4) metal parts and monolithic composites for thickness variation. While multiple element MAUT search units provide near-surface resolution and detection of small discontinuities comparable to 2 D phased array probes, the advantages of MAUT are the ability to provide real-time C-scan data, which facilitates data interpretation and shortens inspection time. Depending on inspection needs, data can be displayed as A-, B- or C-scans, or three dimensional renderings.

The title and scope are in draft form and are under development within this ASTM Committee.