The role of the guide tube in the corrugated expansion joint should not be underestimated. The installation of the guide tube in the corrugated expansion joint requires a smooth flow of medium, reducing the structural vibration caused by changes in fluid flow characteristics when high-speed fluid passes through the corrugated pipe, and protecting the corrugated pipe. When used in working conditions with strong scouring force, it can also play a role in anti scouring and wear resistance, protecting the corrugated pipe from direct scouring by the medium and extending the service life of the corrugated expansion joint.

After running for a period of time, the expansion joint experienced non-standard cracks in the guide tube, which severely shattered and fell off. Analyzing the causes of the damage can help avoid problems during the selection and use process in the later stage. The technical personnel of the expansion joint manufacturer have summarized the following points based on actual applications:

1. After conducting modal and stress analysis on the flow guide tube using finite element method, it was found that the fatigue failure of the flow guide tube was caused by the internal flow excitation of the pipeline, resulting in damage.

2. The inherent natural frequency of the guide tube resonates with the vibration frequency of the piping system, and resonance can easily cause damage to the guide tube.

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

4. Changes in operating conditions can cause vibrations in the piping system or internal media. The phenomenon of resonance between the guide tube and the piping system leads to fatigue, causing cracks and fractures in the guide tube.