METHOD AND EQUIPMENT FOR SECONDARY DETECTION OF DEFECT PART OF ADHESION LAYER OF SANDWICH STRUCTURE PLATE

PURPOSE:To measure the separation part of an adhesion layer securely in two dimensions by irradiating the surface of a honeycomb plate with a parallel light beams at a constant angle and calculating the difference between reflected light intensity distribution in a heated and an unheated state. CONSTITUTION:When a heater 16 is not in operation, namely, when the honeycomb plate 10 is at room temperatures, a measurement area is irradiated with the parallel beam 24 and the reflection intensity distribution image of the reflected wave 26 is photodetected by a photodetector 30. This reflected light intensity distribution image in the reference state is stored in the reference data memory of a measurement data processor 40. Then, the heater 16 is operated to irradiate one Al plate 14A of the honeycomb plate 10 with heat rays. The Al plate 10 where the adhesion layer is peeled deforms, for example, outward in a convex shape. The reflected light intensity distribution image in this state varies according to the thermal deformation state of the surface of the plate 10. The reflected light intensity distribution image in this variation state is stored in the variation data memory of the processor 40. Then, the difference between both intensity distributions is calculated and outputted to a display means to easily recognize the presence of a separation defect part.