ASTM E 2533 : 2021

1.1This guide provides information to help engineers select appropriate nondestructive testing (NDT) methods to characterize aerospace polymer matrix composites (PMCs). This guide does not intend to describe every inspection technology. Rather, emphasis is placed on established NDT methods that have been developed into consensus standards and that are currently used by industry. Specific practices and test methods are not described in detail, but are referenced. The referenced NDT practices and test methods have demonstrated utility in quality assurance of PMCs during process design and optimization, process control, after manufacture inspection, in-service inspection, and health monitoring.

1.2This guide does not specify accept-reject criteria and is not intended to be used as a means for approving composite materials or components for service.

1.3This guide covers the following established NDT methods as applied to PMCs: Acoustic Emission (AE, Section 7); Computed Tomography (CT, Section 8); Leak Testing (LT, Section 9); Radiographic Testing, Computed Radiography, Digital Radiography, and Radioscopy (RT, CR, DR, RTR, Section 10); Shearography (Section 11); Strain Measurement (Contact Methods, Section 12); Thermography (Section 13); Ultrasonic Testing (UT, Section 14); and Visual Testing (VT, Section 15).

1.4The value of this guide consists of the narrative descriptions of general procedures and significance and use sections for established NDT practices and test methods as applied to PMCs. Additional information is provided about the use of currently active standard documents (an emphasis is placed on applicable standard guides, practices, and test methods of ASTM Committee E07 on Nondestructive Testing), geometry and size considerations, safety and hazards considerations, and information about physical reference standards.

1.5To ensure proper use of the referenced standard documents, there are recognized NDT specialists that are certified in accordance with industry and company NDT specifications. It is recommended that a NDT specialist be a part of any composite component design, quality assurance, in-service maintenance, or damage examination.

1.6This guide summarizes the application of NDT procedures to fiber- and fabric-reinforced polymeric matrix composites. The composites of interest are primarily, but not exclusively, limited to those containing high modulus (greater than 20 GPa (3×10⁶ psi)) fibers. Furthermore, an emphasis is placed on composites with continuous (versus discontinuous) fiber reinforcement.

1.7This guide is applicable to PMCs containing, but not limited to, bismaleimide, epoxy, phenolic, poly(amide imide), polybenzimidazole, polyester (thermosetting and thermoplastic), poly(ether ether ketone), poly(ether imide), polyimide (thermosetting and thermoplastic), poly(phenylene sulfide), or polysulfone matrices; and alumina, aramid, boron, carbon, glass, quartz, or silicon carbide fibers.

1.8The composite materials considered herein include uniaxial laminae, cross-ply laminates, angle-ply laminates, and sandwich constructions. The composite components made therefrom include filament-wound pressure vessels, flight control surfaces, and various structural composites.

1.9For current and potential NDT procedures for finding indications of discontinuities in the composite overwrap and thin-walled metallic liners in filament-wound pressure vessels, also known as composite overwrapped pressure vessels (COPVs), refer to Guides E2981 and E2982, respectively.

1.10For a summary of the application of destructive ASTM standard practices and test methods (and other supporting standards) to continuous-fiber reinforced PMCs, refer to Guide D4762.

1.11Units—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.

1.12This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.13This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.