基于失效模式的深海玻纤增强柔性管截面设计

针对深海油气输送所使用的钢制管道存在耐腐蚀性差、质量大以及柔性小的不足,设计了具有耐腐蚀性强、质量轻、强度高、柔性好等优点的热塑性玻璃纤维(玻纤)增强聚乙烯柔性管,基于海深500 m油井油气输送用玻纤增强柔性管道中的抗压和抗拉增强层截面结构设计要求,通过有限元方法进行了多角度玻纤缠绕设计。结合DNVGL–RP–F119规范和美国船级社相关规范,首先根据柔性管受载工况进行了抗压层和抗拉层缠绕角度的设计,然后通过对抗压层、抗拉层在30 MPa内压、5 MPa外压和588 000 N拉力3种典型工况下的厚度试算以及90 MPa爆破压力校核,最终获得能够满足柔性管技术设计指标要求的增强层厚度为11.6 mm(90°玻纤缠绕抗压层8 mm,+30°玻纤缠绕抗拉层1.8 mm,–30°玻纤缠绕抗拉层1.8 mm)。与传统柔性管使用的单一缠绕角度设计方法相比,所设计的玻纤增强柔性管不需要经过多个工况强度校核进行大量缠绕角度和缠绕厚度试算以确定多种工况下的增强层最优缠绕角度和最少缠绕层数,因此计算量小、设计效率高。

Cross Section Design of Glass Fiber Reinforced Flexible Pipe in Deep Sea based on Failure Mode

In order to overcome defects of poor corrosion resistance,large weight and weak flexibility of steel pipelines which are applied to oil and gas transmission in deep sea,the thermoplastic glass fiber reinforced polythene flexible pipes with features of high corrosion resistance,light weight and high strength and good flexibility were designed. Aiming at designing requirements of cross section structure of reinforcement layer including compressive and tensile reinforced layer of glass fiber reinforced flexible pipes which are utilized to transmit oil and gas in deep sea,such as 500 meter deep,the multi-angle glass fiber winding design was carried out based on finite element method. In combination with DNVGL-RP-F119 specifications and American Classification Soci-ety specifications,winding angle design was firstly carried out on the compressive layer and tensile layer according to flexible pipe loading conditions. By calculating the thickness of the compressive layer and the tensile layer in three typical working conditions of 30 MPa internal pressure,5 MPa external pressure and 588000 N tensile force,and checking the blasting pressure 90 MPa, it is obtained that the thickness of the reinforcement layer which meets the design index requirements of flexible tube technology is 11.6 mm (the thickness of 90° fiber winding compressive layer is 8 mm,the thickness of +30° or -30° fiber winding tensile layer is each 1.8 mm). Compared with the traditional design method of single winding angle used in traditional flexible pipes,the design of the glass fiber reinforced flexible pipe does not need to calculating the winding angle and winding thickness largely through checking the intensity of multiple working conditions for determining the optimal winding angle and the minimum number of winding layers in various working conditions,therefore,it has small calculation amount and high design efficiency.