1. Test Purpose

2. Core Test Parameter Requirements

• Number of Cycles
  • General working conditions: ≥1000 cycles (simulating displacement cycles caused by thermal expansion/contraction or vibration of pipelines).
  • Special working conditions (e.g., high-frequency vibration environments): ≥3000 cycles, which can be adjusted based on product design standards or customer requirements.
• Displacement
  • Reciprocating displacement is performed at 100% of the product’s rated compensation capacity (e.g., axial displacement ±X mm, lateral displacement ±Y mm, angular displacement ±θ°), ensuring coverage of the maximum displacement range in actual use.
  • Displacement rate: Typically controlled at 50–100 mm/min to avoid additional impact loads due to excessive speed.
• Environmental Conditions
  • Room temperature test: Applicable to general-purpose fabric expansion joints, with an ambient temperature of 23±5°C.
  • High-temperature test: For high-temperature resistant models, tests must be conducted at the rated operating temperature (e.g., 200°C, 400°C) to simulate actual high-temperature flue environments.
• Loading Method
  • Mechanical reciprocating drive devices are used to achieve periodic displacement loading in axial, lateral, or angular directions, ensuring uniform and stable loading without additional torque or eccentric loads.

3. Test Process Requirements

• Pretreatment
  • Before testing, inspect the sample’s appearance to ensure no initial damage (e.g., loose stitching, fabric tearing, flange deformation).
  • Fix the sample according to actual installation methods, ensuring firm connections at both ends to simulate stress conditions in real working environments.
• Cyclic Testing
  • Each cycle must complete the full process of 'maximum displacement → reset → reverse maximum displacement → reset,' with the number of cycles recorded.
  • Monitor the sample in real-time during testing for signs of fabric tearing, lining detachment, or seal leakage.
• Termination Conditions
  • The test passes if the preset number of cycles is reached without failure.
  • The test must be terminated and deemed unqualified if:
    • The main fabric has through-tearing or large-area damage;
    • The sealing structure fails (e.g., obvious leakage occurs);
    • The connecting flange or metal frame undergoes plastic deformation or fracture.

4. Post-Test Evaluation

• Visual Inspection: Check for wear, deformation, or cracks on the sample.
• Performance Verification: For samples that pass the cyclic test, re-conduct seal performance tests (e.g., air pressure or water pressure tests) to ensure no leakage.
• Report Output: Record the number of cycles, displacement, ambient temperature, and test results as the basis for product qualification certification.