What is an approved method of inspection on composite materials?

The approved method of inspection for composite materials that is widely recognized is thermography. This technique utilizes infrared imaging to detect variations in temperature, which can indicate defects such as delaminations, voids, and other irregularities within composite structures. Thermography is particularly effective because it allows for the examination of large areas quickly and without direct contact with the material, thus preserving the integrity of the composite. This method can also assess the condition of the composite in real-time, making it valuable for both routine inspections and maintenance.

While other methods such as X-ray or visual inspection can also be used, they may not be as effective for certain types of composite defects. For instance, X-ray can be limited by the thickness and density of the material, which may obscure certain structural issues. Visual inspection is more subjective and dependent on the inspector’s experience and ability to discern subtle differences or signs of damage. Dye penetrant can be used, but it typically applies to non-porous materials and might not effectively reveal subsurface issues in composites.

Therefore, thermography stands out as the most suitable method for reliably inspecting composite materials, making it the correct choice among the given options.