The compression fatigue heating test machine is mainly used to simulate the fatigue behavior of materials under repeated compression loads and study the heating caused by fatigue. Its working principle involves the collaborative operation of multiple key systems:

（1） Loading System

The testing machine applies periodic compressive loads to the specimen through mechanical or hydraulic devices. In mechanical testing machines, the crankshaft connecting rod mechanism is usually driven by an electric motor to convert rotational motion into linear reciprocating motion, allowing the indenter to compress the specimen. The hydraulic testing machine uses the pressure of hydraulic oil to push the piston, thereby achieving compressive loading of the sample. The loading frequency and load amplitude can be accurately set and adjusted according to the experimental requirements to simulate the compressive fatigue load experienced by materials under different working conditions.

（2） Displacement measurement system

In order to accurately control the compression displacement and monitor the deformation of the specimen during the fatigue process, the testing machine is equipped with a high-precision displacement measurement device. Common ones include grating rulers, linear variable differential transformers (LVDTs), etc. These sensors can measure the displacement changes of the pressure head in real time and feedback the displacement signal to the control system. The control system adjusts the operation of the loading device based on the displacement signal to ensure that the compression displacement is carried out according to the predetermined parameters. At the same time, it can also record the deformation history of the specimen during the fatigue process, providing data support for analyzing the fatigue performance of the material.

（3） Temperature measurement system

Due to the focus of the experiment on fatigue heating, it is necessary to accurately measure the temperature changes of the specimen during the fatigue process. Usually, thermocouple or infrared temperature measurement technology is used. Thermocouples can directly contact the surface of the sample, measure the temperature at specific points, and convert it into electrical signals for output. Infrared temperature measurement determines the temperature of a sample by detecting the infrared radiation emitted from its surface, and has the characteristics of non-contact and rapid response. These temperature measurement devices transmit temperature signals to the data acquisition system for real-time monitoring and recording of temperature changes in the sample, in order to study the intrinsic relationship between compression fatigue and heat generation.

（4） Control system

The control system is the core part of the compression fatigue heating testing machine, responsible for coordinating the operation of various subsystems and accurately controlling and collecting data from the loading system, displacement measurement system, and temperature measurement system based on preset test parameters. The control system can set parameters such as the size, frequency, and number of tests of the compression load, while monitoring displacement and temperature data in real time. When the preset test conditions are reached or abnormal situations occur, the test can be stopped in a timely manner, and the data can be saved and processed. In addition, some control systems also have data analysis and processing functions, which can directly generate test results such as fatigue curves and heating curves, providing convenient analysis tools for researchers.