Common Fault Analysis and Corresponding Solution Sharing of High speed Tensile Testing Machine

High speed tensile testing machine is a precision equipment used to test the mechanical properties of materials under high-speed tensile conditions, widely used in fields such as aerospace, automotive manufacturing, and new material research and development. Its core advantage lies in the ability to simulate the dynamic response of materials under harsh conditions, such as collisions, and accurately capture the stress-strain relationship of materials during high-speed deformation through loading speeds of several meters to tens of meters per second. Its testing scope is wide, not only applicable to metal materials, but also capable of evaluating the performance of polymer materials, composite materials, and brittle materials under high-speed impact.

Once an abnormality occurs in the high-speed tensile testing machine, it not only affects the validity of the test data, but may also endanger the safety of the equipment. Here are six typical problems and scientific response methods:

1. The force or displacement signal has high noise and jumps

Reason: Loose sensor wiring, electromagnetic interference (such as near the frequency converter), or poor grounding of the high-speed acquisition card.

Countermeasure: Check if the connectors of the force sensor and extensometer are securely fastened; Use shielded twisted pair cables, with the shielding layer grounded at one end; Keep the signal line away from the power cable; If necessary, install signal isolation modules.

2. The actual strain rate deviates significantly from the set value

Reason: hydraulic/servo system response lag, fixture slippage, or incorrect sample size input.

Countermeasure: Regularly calibrate the actuator speed feedback system; Select a clamping surface with matching material hardness (such as tungsten carbide teeth) and apply sufficient clamping force; Ensure the accuracy of parameters such as sample gauge length and thickness in the software.

3. During the experimental process, the specimen fractures or slips prematurely

Reason: Insufficient clamping force, poor alignment of fixtures, or defects in sample processing (such as notches, burrs).

Countermeasure: Use hydraulic self-locking or wedge-shaped fixtures to enhance clamping; Calibrate the coaxiality of the upper and lower clamp heads using a laser alignment instrument (deviation of 0.1mm); The edges of the sample need to be finely polished to avoid stress concentration.

4. Severe vibration or abnormal noise of equipment under high-speed impact

Reason: Insufficient foundation rigidity, worn actuator bearings, or failure of buffering devices.

Countermeasure: Ensure that the equipment is installed on a 30cm thick concrete foundation; Regularly check the clearance of the actuator guide bearing; Verify whether the hydraulic accumulator or gas-liquid buffer is working properly, and promptly charge nitrogen or replace seals.

5. Data collection is not synchronized or peak values are lost

Reason: Insufficient sampling frequency (should be 10 times the strain rate), trigger setting error, or memory card write delay.

Countermeasure: Set the sampling rate (usually 100kHz) according to testing standards (such as ISO26203); Enable the 'pre trigger' mode to capture the moment of fracture; Replace regular SD cards with high-speed solid-state drives.

6. High oil temperature or hydraulic system alarm (hydraulic model)

Reason: Blockage of the cooler, aging of the oil, or heat accumulation caused by continuous high-frequency testing.

Countermeasure: Replace the anti-wear hydraulic oil every 500 hours; Clean the fins of the air-cooled/water-cooled condenser; To avoid prolonged continuous operation at full load, cyclic cooling should be used intermittently during testing.