Wide-temperature-range uniaxial and biaxial compression test device in high-pressure hydrogen environment

A wide-temperature-range uniaxial and biaxial compression test device in a high-pressure hydrogen environment, comprising a test box, a temperature sensor, a gas pressure sensor, test pressure sensors, displacement sensors, an oxygen/hydrogen concentration monitor, an upper computer, a hydrogen filling system, a vacuum extraction system, and a Digital Image Correlation (DIC) test system, wherein a sample clamping mechanism, a heating system and a cooling system are arranged in the test box;

• the upper computer is electrically connected to the temperature sensor, the gas pressure sensor, the test pressure sensors, the displacement sensors, the oxygen/hydrogen concentration monitor, the hydrogen filling system, the DIC test system, the sample clamping mechanism, the heating system, the vacuum extraction system and the cooling system, respectively;
• the hydrogen filling system is connected to the test box through a pipeline;
• the temperature sensor, the gas pressure sensor and the oxygen/hydrogen concentration monitor are arranged inside the test box;
• the vacuum extraction system is connected to the hydrogen filling system and the test box through a pipeline, respectively;
• a uniaxial compression test mode and a biaxial compression test mode are implanted in the upper computer;
• the upper computer is configured to acquire test parameters in the uniaxial compression test mode or the biaxial compression test mode, and to generate a test instruction based on the test parameters;
• the test instruction is configured to start the hydrogen filling system, the temperature sensor, the gas pressure sensor, the test pressure sensors, the displacement sensors and the oxygen/hydrogen concentration monitor;
• the test pressure sensors and the displacement sensors are arranged on the sample clamping mechanism;
• the hydrogen filling system is configured to fill hydrogen into the test box;
• the upper computer is configured to generate a hydrogen filling instruction based on a gas pressure in the test box acquired by the gas pressure sensor;
• the hydrogen filling system is configured to execute the hydrogen filling instruction;
• the upper computer is configured to acquire temperature data in the test box acquired by the temperature sensor, and to generate a heating/cooling instruction based on the temperature data;
• the heating system and the cooling system are configured to execute the heating/cooling instruction until temperature in the test box reaches a set value;
• the upper computer is configured to generate a sample clamping instruction based on the test parameters;
• the sample clamping mechanism is configured to execute the sample clamping instruction;
• the upper computer is configured to acquire data acquired by the test pressure sensors and data acquired by the displacement sensors, and to determine a compression rate of a sample according to the data acquired by the test pressure sensors and the data acquired by the displacement sensors;
• when the compression rate of the sample reaches the set value, the upper computer generates a sample clamping stop instruction;
• the sample clamping mechanism is configured to execute the sample clamping stop instruction;
• the DIC test system is configured to acquire sample image data during the test process;
• the upper computer is configured to determine stress-strain data of the sample based on the sample image data and the data acquired by the test pressure sensors, to obtain a constitutive model for characterizing nonlinearity of the sample by screening from a database based on the stress-strain data, and to generate a strain distribution nephogram of the sample based on the constitutive model, to analyze a change process of the strain distribution nephogram to obtain a deformation behavior and a failure fracture mechanism of a sample material;
• and
• the vacuum extraction system is configured to vacuumize the test box;
• the hydrogen filling system comprises a nitrogen gas cylinder, a hydrogen gas cylinder, a buffer tank, a first tee joint, and a second tee joint;
• the nitrogen gas cylinder is connected to a first interface of the first tee joint through a pipeline;
• a gas molecular filter and a nitrogen manually-operated valve are arranged on the pipeline between the nitrogen gas cylinder and the first interface of the first tee joint in sequence;
• the hydrogen gas cylinder is connected to a second interface of the first tee joint through a pipeline, and a gas molecular filter and a hydrogen manually-operated valve are arranged on the pipeline between the hydrogen gas cylinder and the second interface of the first tee joint in sequence;
• a third interface of the first tee joint is connected to a pipeline of a cooler;
• the cooler is connected to the buffer tank through a pipeline;
• a pressure sensor, a pressure gauge, an electromagnetic pneumatic valve and a booster pump are arranged on the pipeline between the third interface of the first tee joint and the cooler in sequence;
• the buffer tank is connected to a first interface of the second tee joint through a pipeline;
• a second interface of the second tee joint is connected to the test box through a pipeline, a further pressure sensor and a further pressure gauge are arranged on the pipeline connecting the second interface of the second tee joint and the test box, and a third interface of the second tee joint is connected to the vacuum extraction system through a pipeline.