دانلود مقاله A study on the behavior and strain concentration in offshore steel pipeline with concrete coating under combined loads using Finite Element Analysis
سال انتشار: ۱۳۹۱
محل انتشار: نهمین کنگره بین المللی مهندسی عمران
تعداد صفحات: ۶
Pooya Kheiri – University of Tehran, Tehran, Iran
Moharram Dolatshahi –
It is surely important for offshore pipeline industries to reach accurate and reliable modeling of the strains in concrete coated pipelines. It should be noted that because of the ability of concrete coating in bearing compressive strains, there are huge strains in steel at field joints (FJ). Most pipelines consist of approximately 12m long welded joints. The body of each joint is covered by a corrosion coating, often asphalt, and a concrete cover for weight and protection purposes. However, approximately 35cm at each end remains uncover to allow welding at field joints. In the past, pipelines were designed using stress based criteria. Deeper waters and also new techniques for installing impose very large strains and lead to uneconomic designs, so it is important to use strain base design (SBD), which was developed during nineties. SBD takes advantage of the plastic deformation ability of steel. In the current practice, a new approach is presented to consider the tension which is imposed at tensioner along with bending that occur in stinger, with an accurate finite element (FE) method, which has not be done previously. In this paper a framework for finite element modeling of concrete coated pipelines is presented and has been verified with the test results available in literature. It should be noted that, no laboratory tests data are available for the collapse behavior of huge concrete coated pipes caused by combined tension and bending loads, however impact of tension loads can be measured by comparing the results of bending tests with current practice results. All of abovementioned aspects are described and modeled appropriately using FE software ABAQUS, regarding modeling of three concrete, steel and ACL layers with appropriate meshes and concrete sliding towards the FJ and concrete cracking and crushing, the results can be reliable and applicable.