The role played by the guide cylinder in the corrugated expansion joint is not to be underestimated, the flow medium of the corrugated expansion joint installed with the guide cylinder should be stable, which reduces the structural vibration caused by the change of fluid flow characteristics when the high-speed fluid passes through the corrugated pipe, and plays the role of protecting the corrugated pipe. When used in the working environment with strong scouring force, it can also play the role of anti-scouring and wear-resistant, so that the bellows are protected from direct scouring by the medium, and the bellows are protected to extend the service life of the corrugated expansion joint.

After the expansion joint has been running for a period of time, the guide cylinder has non-standard cracks and falls after serious fragmentation. Analyze the causes of damage, and avoid problems in the later selection and use process. The technical personnel of the expansion joint manufacturer summarized the following points according to the actual application:

1. After the modal and stress analysis of the guide cylinder through the finite element method, it was concluded that the application pipeline was damaged due to the fatigue damage of the guide cylinder caused by the vibration of the internal airflow.

2. The natural vibration frequency of the guide cylinder resonates with the vibration frequency of the pipe system, and the vibration frequency is similar.

3. During operation, the flow rate of the circulating medium suddenly changes and the internal pressure of the pipeline system suddenly increases.

4, the use of conditions change, so that the vibration of the pipe system or the internal medium changes. The phenomenon of resonance between the tube and the pipe system leads to fatigue, which causes the tube to crack and fracture.