球形防喷器关键结构失效分析与结构改进研究

Study on failure analysis and structural improvement for key structures of spherical BOP

为减少或预防球形防喷器关键结构失效事件发生,结合现有球形防喷器结构和工作原理,对FH35-35型球形防喷器活塞行程、胶芯挤胶量等参数进行理论计算。通过对胶芯材料进行单轴拉伸、压缩和平面拉伸试验,取3组试验数据进行优化处理,得到胶芯材料的优化本构模型。同时,建立球形防喷器全尺寸三维模型,对该模型进行有限元计算,分析胶芯和支架的应力和变形规律,找到胶芯和支架失效的内在原因,并对胶芯和支架进行结构改进。研究结果表明:通过改变胶芯斜向下的倒角结构,并将支架上板块厚度由原来的40 mm增加为50 mm,改进后胶芯上部某处应力相对改进前降低23.9 MPa,支架背部的最大应力相对改进前降低约46.8~187.5 MPa,改进后的胶芯与支架有效提高防喷器强度,并且胶芯在现场使用情况良好,研究结果可为高性能球形防喷器的设计和制造提供一定参考。

In order to reduce or prevent the failure of key structures of the spherical blowout preventer(BOP),combined with the structure and working principle of the existing spherical BOP,the theoretical calculation was conducted on the piston stroke,extrusion amount of rubber core and other parameters of the FH35-35 spherical BOP.The uniaxial tension,compression and plane tension tests of rubber core material were carried out,then the three types of test data were optimized,and the optimized constitutive model of rubber core material was obtained.Meanwhile,a full-scale three-dimensional model of the spherical BOP was established,and the finite element calculation was carried out on the model.The stress and deformation laws of the rubber core and the support were analyzed,then the internal reasons for the failure of rubber core and support were found,and the structure of rubber core and support were improved.The results showed that through changing the oblique downward chamfering structure of the rubber core and increasing the thickness of upper plate of the support from 40 mm to 50 mm,the stress at the upper part of the improved rubber core is reduced by 23.9 MPa compared with that before the improvement,and the maximum stress at the back of the improved support is reduced by about 46.8~187.5 MPa compared with that before the improvement,that is,the improved rubber core and support effectively improve the strength of BOP.The improved rubber core is used well in the field.The research results can provide some reference for the design and manufacture of high performance spherical BOP.