Urgent, I need the advice of experts regarding stress calculation after a device failure
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Cracks occurred at the welds between the pipes and flanges, leading to a hydrogen leak that caused an explosion. The pipes were exposed to high temperatures (estimated at 600–1000 degrees). When the cracks opened, the internal pressure (around 5 MPa) generated tremendous force. After the fire was extinguished, the pipes did not return to their original position; there was a gap of more than 10 cm at the break site. In such a situation, if the owner wishes to reconnect and use the pipes again (assuming that the inspection agency believes they can still be used), how would experts carry out the stress calculations? ? ?
The pipeline should be unusable now; actually, the stress calculation can be done using the standard methods as usual
The pipeline fractured at the weld joint with the flange, resulting in a hydrogen leak that caused an explosion; I think it would be necessary to analyze what caused the fracture afterward – was it a welding issue? Is it caused by stress issues instead? Personally, I think the pipes should be replaced.
The owner doesn’t want to replace it, and suitable materials are not available for now; the supervisor wants me to use cold stress calculations. Is that okay?
How do you plan to reconnect and use it? Are cracks over 10 cm signs of pipe deformation?
In other words, the pipe at the 10mm gap is cut off, and the pipes at both ends are welded together by cold welding. However, cold tightening is generally used on high-temperature pipes; I’m not sure if it’s suitable for your pipe.
Moreover, the dimensions of the cold seal also need to be calculated; it’s not appropriate to simply increase them by 10 cm just because there’s a 10-cm gap – that wouldn’t make sense.
It is estimated that the owner has already used hinges to pull the pipes on both sides together and welded them. If a cold-compression simulation is used for calculation, it is not possible to determine the stress levels; so how can one assess the potential hazards?
Generally, pipes with temperatures exceeding 430 degrees require cold straining; specific regulations can be found in relevant standards. In the event of an accident, considering a shorter amount of cold tightening may not be appropriate, unless cold tightening is indeed necessary, and that amount happens to be the right one. Then let’s calculate it based on cold tightening. It seems like your project doesn’t pay much attention to security!