Infrared Thermal Stress Analysis (IR-TSA)

The IR-TSA system is a tool that is used to create full-field stress measurements on a bridge detail, such as a welded connection or stiffeners. The system quantifies applied stresses based on the principles of thermoelasticity, i.e. the thermal energy generated in a material by the application of stress. Thermoelasticity states that an object subjected to mechanical stress undergoes a change in volume which in turn causes a variation in the object’s temperature. Very small changes in temperature are measured with a thermal camera, which is then related to the change in the sum of the principle stresses. The IR-TSA is designed to assess fatigue prone details on highway bridges, identify stress concentration, and assess welded connections in light poles and sign supports, among other applications. The instrument can provide a full-field image of an area on a structure, visually showing the stress distributions in the measurement area.