撞击载荷下水下管汇动力响应研究

Dynamic response of subsea manifold subjected to impact loading

水下管汇是水下生产系统的关键设备之一,其所处的复杂海洋环境承受着极其多变的环境载荷.以水下管汇为研究对象,分析其受落物撞击的影响.利用双线性随动强化模型模拟水下管汇,LS-DYNA求解器计算不同厚度防护板的水下管汇在霍尔锚横向、纵向和30°倾斜3个角度下的撞击过程.研究表明:防护板厚度越大,所吸收碰撞的能量占管汇吸收能量的比率就越小,相反受到冲击时的变形抗性就越大;同等撞击载荷下,5～8 mm厚度防护板既能够有效控制撞击凹陷深度又能吸收较多的冲击能量;在船锚的碰撞过程中,距离撞击位置最近的管系接口影响最大.同时,锚击还会在管系中管道连接处和弯管处产生应力集中;与管系相连接的闸阀在振动过程中产生的加速度幅值与防护板厚度和撞击角度并无太大关系.

The manifold is one of the key pieces of equipment in subsea production system, and it is installed in complex marine environment with varied loads. The impact of falling objects on the manifold is analyzed. By employing the bilinear follow-up intensified model and using the LS-DYNA solver, the impact stress and deformation of the manifold with different thickness protective plates is calculated. The collision angle of hall anchor is considered as transverse, longitudinal and 30 degree of inclination. The result shows that the larger the thickness of protective plate, the smaller the ratio of energy absorbed by protective plate, however, the protective plate has greater ability of resisting the deformation. With the same impact load, the thickness of 5~8mm protection plate can control the pit depth and absorb impact energy. During the process of impact, the closest hub has the biggest influence. The stress concentration in the tee and bend of the pipeline is caused by anchors’ impact. The acceleration amplitude of the valve is nearly unrelated to the thickness of the protective plate and the impact angle.