Novel detection approach for thermal defects: Study on its feasibility and application to vehicle cables

Abstract It is important to accurately assess the thermal defect state of equipment to ensure its safe operation. A novel thermal defect detection method called the square even‐order derivative method is proposed. First, the derivative functions of temperature were constructed to investigate the main‐side‐peak characteristics of the derivative curve, and the mathematical expressions for the position, depth, intensity of the defects, and parameters of the derivative curve were deduced, which can be used to quantitatively detect the defects. Then, numerical and experimental analyses of an example case of defected epoxy resin plates were carried out to verify that thermal defects can be effectively and accurately detected by the proposed method. Finally, the method was applied to a vehicle cable to detect its thermal defects in another example case of defected vehicle cable, which preliminarily validated the feasibility of the proposed method in practical applications.