NEWLY INTRODUCED MICRO-FOCUSED X-RAY CT SCANNERAND PULSED THERMOGRAPHY SYSTEM FOR NDE OFCOMPOSITES AND APPLICATION EXAMPLES

摘要

ISTA/JAXA had been assigned to enhance itsNDE capability in an improvement of reliabilityproject in space field. A micro-focused X-ray CTscanner (Micro CT) and pulsed thermography wereintroduced in the project. The Micro CT can detectrelatively quite small damage/defect and the pulsedthermography can be easily applicable to large areaof structure. Some NDE examples with these newlyintroduced equipments are shown in this paper.The first example is Micro CT result of3-dimensional carbon/carbon composite specimenfor Iosipescu shear test. It is distinct that crackswere detected both between fiber/matrix interfaceand inside of fiber bundles, and it was obtained thatthe crack gap sizes were from several μm to severaldozen μm from Micro CT data. The minimumpixel size of Micro CT is 5 μm with scan area ofdiameter of about 5 mm, but there is a possibilityof detect of damage/defect smaller than that ifcontrast medium can be penetrated to thedamage/defect. Other two successful examples ofMicro CT are also shown in this paper. From theseresults of Micro CT, small size of damage/defect,such as matrix crack, void and delamination can benondestructively evaluated. Moreover, a series ofMicro CT slices can be converted to 3-dimensionalCAD data, IGES or STL format. From thisconversion, it is easy to obtain reverse engineeringor converted slice position and/or angle. The shapeand position of damage/defect can be easilyevaluated with this software.Pulsed thermography has been also introducedand applied to NDE of composite materials. Someof the successful results are presented in this paper.This technique is a fast and non-contact NDEtechnique for large area and is good for detection ofdelamination in composites. Pulsed thermographyhas shown high potentiality for NDE of compositeproducts.Consequently, NDE capability of damage/defecthas been enhanced at ISTA/JAXA with newlyintroduced Micro CT and pulsed thermography, andthen these equipments can be powerful tool fordoing research on composites in space field.