Characterization of impact damage in metallic/nonmetallic composites using x-ray computed tomography imaging
- US Army Research Laboratory/Weapons and Materials Research Directorate, Aberdeen Proving Ground, Maryland 21005 (United States)
Characterizing internal impact damage in composites can be difficult, especially in structurally complex composites or those consisting of many materials. Many methods for nondestructive inspection/nondestructive testing (NDI/NDT) of materials have been known and in use for many years, including x-ray film, real-time, and digital radiographic techniques, and ultrasonic techniques. However, these techniques are generally not capable of three-dimensional (3D) mapping of complex damage patterns, which is necessary to visualize and understand damage cracking modes. Conventional x-ray radiography suffers from the loss of 3D information. Structural complexity and signal dispersion in materials with many interfaces significantly effect ultrasonic inspection techniques. This makes inspection scan interpretation difficult, especially in composites containing a number of different materials (i.e., polymer, ceramic, and metallic). 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 (that is, radiological density and geometry) images of thin cross sections through an object. Because of the absence of structural superposition, images are much easier to interpret than conventional radiological images. The user can quickly learn to read CT data because images correspond more closely to the way the human mind visualizes 3D structures than projection radiology (that is, film radiography, real-time radiography (RTR), and digital radiography (DR)). Any number of CT images, or slices, from scanning an object can be volumetrically reconstructed to produce a 3D attenuation map of the object. The 3D attenuation data can be rendered using multiplanar or 3D solid visualization. In multiplanar visualization there are four planes of view that can be defined to be anywhere in an object. These visualization modes produce easily interpretable images with very good spatial resolution and excellent dimensional capability. This paper will discuss current applications of advanced CT imaging to characterizing impact damage in metallic/nonmetallic composites. Examples, including encapsulated ceramics in metal-matrix-composites, will be discussed.
- OSTI ID:
- 21207701
- Journal Information:
- AIP Conference Proceedings, Vol. 497, Issue 1; Conference: 9. international symposium on nondestructive characterization of materials, Sydney (Australia), 28 Jun - 2 Jul 1999; Other Information: DOI: 10.1063/1.1302065; (c) 1999 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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