Development of Temperature-strain Prediction Based on Deformation-induced Heating Mechanism in SCM440 Surface Cracked Shaft under Ultrasonic Excitation

The mechanisms behind temperature and material deformation in vibrothermography remain questionable, presenting a gap in understanding. This study investigates the deformation-induced mechanism, focusing solely on the heat generation associated with strain development. Both experimental and simulation approaches are incorporated. The experimental segment explores the temperature-strain relationship of SCM440 material, commonly used for rotating shafts. This behavior is examined through the connection between temperature change and material deformation during a uniaxial tensile test. Results indicate that temperature change and distribution can be predicted based on plastic strain development. Finite Element Method (FEM) simulation is utilized to model the excitation of a shaft with and without an elliptic surface crack. Various cracked shaft configurations are investigated, revealing distinct strain generation and distribution patterns. High strain alteration is notably observed around the crack tips, enabling the detection of shaft discontinuity. Consequently, a temperature prediction technique is developed to estimate temperature based on strain alteration during deformation. Adequate excitation power and the use of a high-sensitivity IR camera are recommended for the effective application of the temperature prediction technique. Additionally, this study provides insights into understanding the utility and limitations of vibrothermography for inspecting engineering component damage based on experimental temperature-strain relationships and computational predictions of strain distribution in cracked shafts under excitation. These findings offer guidance for engineering applications and future research endeavors.