Nondestructive Characterization of Impact Damage in Metallic/Nonmetallic Composites Using X-ray Computed Tomography Imaging

摘要

Characterizing internal impact damage in composites can be difficult, especially in structurally complex composites or those consisting of many materials. Many methods for the nondestructive inspection/nondestructive testing (NDI/NDT) of materials have been known and used for many years, including x-ray film, real-time and digital radiographic techniques, and ultrasonic techniques. However, these techniques are generally not capable of mapping three-dimensional (3-D) complex damage patterns, which is necessary to visualize and understand damage cracking modes. X-ray computed tomography (CT) is broadly applicable to any material or test object through which a beam of penetrating radiation may be passed and detected, including metals, plastics, ceramics, metallic/nonmetallic composites, and assemblies. The principal advantage of CT is that it provides densitometric (e.g., radiological density and geometry) images of thin cross sections through an object. Because of the absence of structural superposition, the images are much easier to interpret than conventional radiological images. This report discusses current applications of advanced CT imaging to characterizing impact damage in metallic/nonmetallic composites. Examples, including encapsulated ceramics in metal matrix composites, will be presented.