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2012
Conference Paper
Titel
Improved defect detection with combined shearography and thermography
Abstract
The requests on non-destructive testing methots are constantly growing because of efficient use of material properties. To fulfill those requests often not only one testing system is sufficient. Therefore a trend in non-destructive testing goes to multi-sensor systems. Because of the casual relation of thermal strain and heat flow through a test object a multi-sensor system of thermography and shearography offers high capability. With thermography singularities of the temperature field on the testing objects surface can be detected and with shearography it is possible to visualize the deformation gradient on the surface. Both methods are using energy which is driven into the testing object. Studies on carbon fibre laminate structures showed, that is possible to improve the rate of defect detection by using a multi-sensor system combination of active thermography and digital shearography with thermal excitation. The study also proved, that because of the redundance of the methods the confidence of defect detection would be higher, which offers new options for automatic defect detection i.e. by using neural network techniques.