Accession Number : ADA259412


Title :   Nondestructive Evaluation of Composites Using Infrared Imaging


Descriptive Note : Final rept.,


Corporate Author : ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS


Personal Author(s) : Todaro, Mark E ; Doxbeck, Mark A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a259412.pdf


Report Date : Nov 1992


Pagination or Media Count : 18


Abstract : Benet Laboratories is pursuing methods for nondestructively evaluating composite materials and structures associated with large caliber gun tubes, including items already being manufactured, such as the bore evacuator, as well as experimental items, such as the thermal shroud and composite- reinforced gun tubes. Typical needs include identifying delaminations between the composite and a substrate, delaminations between composite layers, damage from later manufacturing processes, and impact damage during use. Recent in- house work included obtaining images of delaminations in fiber-reinforced, layered composite plates using an infrared video system. The surface of the composite was briefly heated by quick pass with a hot air gun, while an infrared video camera recorded the changing pattern of infrared radiation emitted from the heated surface. From the intensity of this radiation, the system calculated the temperature at each scanned element of the surface for subsequent display, storage, and processing. The surface cools primarily by diffusion of heat into the bulk of the material; and discontinuities, therefore, tend to block the flow of heat and inhibit cooling. In these experiments, the surface of the composite above a delamination did not cool as quickly after heating as the surrounding regions. In the frames recorded immediately after the pass of the hot air gun, the surfaced above delaminations were clearly visible as hot spots. A one- dimensional finite difference algorithm was used to model transient surface temperatures due to an energy pulse incident on a layered material, such as a composite, with or without delaminations.... Composites, Nondestructive evaluation, Delaminations, Infrared imaging.


Descriptors :   *NONDESTRUCTIVE TESTING , *COMPOSITE MATERIALS , *INFRARED IMAGES , ALGORITHMS , TRANSIENTS , MEASUREMENT , RADIATION , TEMPERATURE , AIR , MATERIALS , REGIONS , DEPTH , COOLING , LASERS , SUBSTRATES , INTENSITY , STRUCTURES , ENERGY , ONE DIMENSIONAL , INFRARED RADIATION , GUNS , STORAGE , FRAMES , FLOW , DIFFUSION , WORK , HOT SPOTS , LABORATORIES , AIR GUNS , TUBES , BORES , DELAMINATION , SURFACE TEMPERATURE , DISCONTINUITIES , HEAT , PATTERNS , CAMERAS , IMAGES , HEATING , PLATES , PULSES , SURFACES , TIME , PROCESSING , LAYERS , MODELS , FIBERS , MANUFACTURING , IMPACT , DAMAGE


Subject Categories : Laminates and Composite Materials
      Guns
      Optics


Distribution Statement : APPROVED FOR PUBLIC RELEASE