Piping cyclic loading

Pipe, valve, and fittings tables must specify which size of each class of pipe is threaded, flanged, or socket welded. ANSI B31.3 provides no specific guidance except that it suggests that threads be avoided where corrosion, severe erosion, or cyclic loading is anticipated. 

The drilling vessel and consequently the drill pipe will tend to experience a cyclic loading because of the nature of open water operations. To reduce this cyclic load effect, heave compensators are utilized as discussed earlier. Unfortunately, heave compensators do not... 

Conditions where the pipe is under cyclic loads may result in increased crack growth rates. Operating pressures for a large-diameter pipe can measure up to 8700 kPa (1250 psi). The pipeline pressure continually fluctuates due to loadiug aud unloading of product and is influenced by pump activity. This applies to both gas and liquid hues but has greater influence in liquid systems [6]. 

The following section documents 25 years service life of an epoxy pipe-fine used to transport crude oil from oil wells to a collection station. This work shows the predictability and the long term service life of the pipes under cyclic load. 

Take-off connections should withstand all stresses in the piping system, including those induced by cyclic loading. 

For the three conditions of riser pipe described above, isolated static load, combined static loads and cyclic load cases were simulated. 

Construction components of estate drainage systems within buildings, such as pipes, fittings, and pipe couplings for the connection, transporting, and collection pipelines must be suitable for a maximum waste water temperature of 368 K (95 C) at an ambient temperature of 283 K (10 C). The corresponding usability is checked in a system test under cyclic and continuous loading conditions [2]. 

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