What is Vibration induce cracking

Vibration Induced Fatigue; 

Vibration Induced Fatigue is a form of fracture due to fatigue, mechanical (of mechanical Fatigue) due to Dynamic load caused by vibration ( with Vibration) had done so at the risk of Vibration Induced Fatigue is a point there. High stress and severe shaking points.

This type of damage is usually found at the small branch connections of Pressure Vessel and Piping, which are naturally high-stress points because they are discontinuous (see Stress Analysis) and are the receiving points. Vibrating force Thus, if the Support inadequate and the Small Branch Connection with Vibration ( for example, near or adjacent to the Pump or Compressor), it will cause Vibration Induced Fatigue.

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The figure marks Crack caused Vibration Induced Fatigue at the bottom of the weld of Small branch connection of Pressure vessel ‘s

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Vibration Induced Fatigue – Example 1; 

Examples of damage from Vibration Induced Fatigue is a crack (Crack) in the first  Fatigue Crack that occur on Socket Weld Branch Connection by cracks that occur at welding. The second picture is a Small-bore branch for Chemical Injection is designed to Gusset forward Support, but Support is inadequate or inappropriate Resulting Fatigue Crackup in both the Socket the Weld of Branch Connection and Gusset the time we meet Fatigue Crack. And don’t forget to do PT / MT to find the extent of the cracks And expand the results to nearby areas that are at risk as well.

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Vibration Induced Fatigue – Example 2; 

In another example of Crack on the Vibration Induced Fatigue by Crack place that occupies Weld Toe of the Socket by Branch Connection, which is the Line condensate at a branch of the pipeline High-pressure steam header to Steam trap. In Case. we have corrected by adding Gusset to strengthen the Small branch connection.

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Vibration Induced Fatigue – Example 3; 

See more examples of Vibration Induced Fatigue caused to Pressure Vessel does it in a Stainless Steel Ethylene Filter with Vibration Fatigue Cracking occurs at the Small branch connection of Drain line by Crackup at Base material of Pipe. Weld Toe of the Socket weld plate do joint, and in Case of this, we have already corrected by adding Gusset to strengthen the Small branch connection.

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Vibration Induced Fatigue – Inspection Optimization 1; 

The API-Based Risk’s the RP 581, Inspection ( an RBI) said that checking for Crack caused by Vibration Induced Fatigue is showing how inappropriate RBI Assessment results.

1. The starting point or the cracking or cracking in the forming process is very small and difficult to detect.

2. Fatigue Crack, when formed, will expand very quickly It is prone to damage before the inspection cycle.

3. Crack often occurs and expands in difficult to detect areas such as fillet weld toes, First unengaged thread root, and Defect in another welding.

4. Crack can occur either from the inside of the material (Embedded defect) or on the other side of the material. Which can be difficult to detect.

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Vibration Induced Fatigue – Inspection Optimization 2; 

For   Vibration Induced Fatigue,  the suitable method is How to prevent by detecting and fixing the vibrating spot – The point of conflict or the pulling of the pipe to prevent Fatigue Cracking from occurring which can generally be done as follows

1. A visual look at the various Pipe supports whether it can function as a function or not. Is there any jam?

2. Install Support for small branch connection that has proper vibration, especially for the Small branch connection that connects to Valve or Controller which must support the weight. The risk of Fatigue Cracking easily.

3. Measure the vibration of the pipe using the vibration meter or use touch which requires experience (Usually the pipes should not vibrate more than the vibrations of the car engine at Idle speed)

4. A visual look at the various Fillet welded supports because this point is usually the first Crack location. Therefore, if we encounter Crack, it will help indicate the vibration problem that is occurring.

5. Check by PT / MT method according to the vibration point and the vibration strength point But must be done with enough frequency to work.

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