الفهرس | Only 14 pages are availabe for public view |
Abstract The ever-increasing demand for petroleum has resulted in a wide increase in offshore projects. Therefore, pipelines have been constructed in various areas each having its environmental conditions as temperature, pressure, and axial forces. Elastic and inelastic responses in the pipeline are observed. Thus, to prevent those forces from affecting the pipeline, buckle arrestors are fitted. This thesis studies offshore pipelines stiffened with buckle arrestors. The buckle arrestor’s shape was chosen after making a comparison between three different configurations of buckle arrestors on a model. Finite element analysis using ANSYS software was carried out on pipeline models to assess their strength. The cost of each configuration was estimated. A comparison has been made based on material and scantling properties. The basis of comparison is the weight of the pipe. Three factors that affect those are the percentage of stiffener weight to pipe weight, length of cutting, and weight of weld. The results show that the manufacturing costs of longitudinal and sinusoidal stiffeners were almost the same, but the difference the between critical buckling load of them was the conclusive item in making continuous stiffener the most effective type. Therefore, it was chosen to complete the study. After calculating the hydrodynamic forces acting on the pipeline to determine the actual pipeline’s suitable buckle arrestor’s dimensions. A pipe of an outer diameter of 36” approximately 0.9144 m and wall thickness of 0.0307 m and 60 meters long and the buckle arrestor was calculated to be 250x10 mm. The combined loads from the current and wind were calculated using Morison’s equation to assure the lateral and vertical stability of the pipeline. The resultant force was 216.96 N/m vertically and 238.86 N/m horizontally. Then it was verified using ANSYS to assure the integrity of the pipeline. The final results show that the maximum deformation value is 48.8 mm while the Von Mises Stress of 150.44 MPa which is acceptable compared to the material’s yield stress of 235 MPa. |