| In the Sonic IR imaging Non-Destructive Evaluation (NDE) technique, a short ultrasonic pulse (typically a fraction of a second) produced by a ultrasonic transducer is applied to the target to excite the defects to heat-up, while an infrared camera system images the time evolution of the heating effect to identify the defective area in the target. The heat generated by the defect causes a temperature rising in the adjacent area around the defect. As the energy diffusion takes place, bigger and bigger area is warmed up. Once the excitation source is taken away, energy diffusion and radiation cause the temperature of the area around the defect drop and finally reach the room temperature. All these temperature change would be recorded by an IR camera, with those IR image acquired by the IR camera, a plot can be formed to demonstrate the energy change. The closure effect is an important factor for sonic IR imaging on detection of cracks. The clamping force applied to the crack tends to prevent the crack interface from rubbing against each other so that less heat is generated. The crack energy calculated from the relative velocity correlates in general to the thermal IR intensity of a reasonably determined area at the crack. FPCS was developed to do the associate energy analysis job. |
