A Finite Element Investigation of Existing Pipework Vibration Acceptance Criteria

Abstract

In this thesis, a literature review was conducted to cover the assessment techniques for Oil and Gas (O&G) pipework that includes Small Bore Pipes (SBP). The various methods that were studied are the most commonly found in the field today. The advantages and disadvantages were analyzed. Multiple studies performed for the SBP connection which is the most susceptible area for fatigue failure (where it is usually welded on). A robust Finite Element Analysis was carried out that initially analyzed the variations to the maximum stress, SBP tip velocity, and the first mode by changing the geometry of the system including the length and schedule of pipes. Finally, a sample system was designed, and hundreds of results were gathered from the FEA models which were fed to multiple machine learning programs that trained them. To evaluate the accuracy of the programs, a sample system‘s geometrical parameters were inputted, the first mode frequency was predicted, and the percentage error was calculated. The output of this research would help inspectors to determine the system’s first natural frequency easily and thus expedite the fatigue risk assessment using existing vibration guidelines such as ASME.