Secondary temperature fluctuation in cracked 1020 steel specimen loaded monotonically

The thermal fluctuation in a compact tension specimen made of 1020 steel is monitored as it is loaded monotonically at a constant rate of 0.02 in/min. Cooling prevailed in a region near the crack tip for approximately three and one-half minutes before the local temperature rose above that of the ambient condition. Such a cooling/heating phenomenon has also been observed previously in other materials, either metallic or nonmetallic. What was unexpected is a secondary temperature fluctuation even though the load on the specimen kept increasing. This is a measurable and predictable phenomenon from the energy density theory. It is inherently associated with the change of order and/or disorder in the system that undergoes damage in an irreversible manner. Such a behavior is exhibited by the -function that serves as a measure of the order or disorder in a physical process. Experimental data and analytical predictions are presented to confirm the phenomenon of secondary temperature fluctuation in a cracked specimen.