Metal fatigue test generally has a long test cycle and high test cost. In order to shorten the test time and reduce the test cost, the energy method has become one of the important methods of fatigue test research. The fatigue process of metal materials is a process of energy consumption, and the temperature change caused by the change of sample energy can become an important reference for the study of sample fatigue process.
Infrared thermal imaging technology is a wavelength conversion technology, which can convert the thermal radiation of the target sample into visible light. The difference of thermal radiation of each part of the target sample is used to synthesize a two-dimensional visual image. Computer image processing technology and infrared temperature measurement calibration technology are used to display, analyze and accurately measure the temperature field distribution on the surface of the target sample.
The test is generally carried out on the high-frequency fatigue testing machine. The test parameter accuracy of the infrared thermal imager shall be no more than ± 0.1 ℃ when it meets 100 ℃. The material used in the test is usually the metal material with galvanized surface and normalized treatment. In order to increase the specific emissivity of the metal surface, a thin layer of infrared transmission coating is usually coated on the surface of the sample during the test. The sample shall be designed according to the requirements of normal plate sample of fatigue testing machine and the needs of infrared thermal image testing, and shall comply with the provisions of GB / t3075-2008 axial force control method for fatigue testing of metallic materials.