Influence of loading rate on the infrared radiation of PMMA

Infrared thermography has widely been used in observing and recording failure processes. The loading rate is a critical parameter that influences the infrared radiation (IR) in the mechanical experiment. However, little work has been done regarding its influence on infrared radiation. In order to conduct an in-depth study on the influence of loading rates on IR, a series of three-point bending experiments were conducted on PMMA samples for the IR test. Then, the influence was explained through a physical model derived from the first law of thermodynamics. The experimental results showed that under a fixed loading rate, the change rate of the IR emission was constant, and the relationship between the IR emission and loading time exhibited a linear trend. The variation between the change rate of IR emission and the loading rate can be expressed by the exponential function. The insights gained from this study will be of assistance to obverse the loading processes by infrared thermography.