A multibody system including a drilling riser system, tensioners and a floating platform is key equipment for offshore oil and gas drilling. Most of the previous studies only focus on the drilling riser system rather than the multibody system. Mechanical characteristics of the deepwater drilling riser system cannot be analyzed accurately in a simplified model. Therefore, a three-dimensional multibody analysis program is developed. The static and dynamic characteristics of the deepwater drilling riser system under different platform motions are analyzed based on the developed program. The results show that the static displacement of the riser system with tensioners is smaller than that without tensioners, which means the tensioners can suppress the deformation of the riser system. Under surge and sway motions of the platform, the dynamic displacement of the riser system with tensioners is also smaller than that without tensioners due to the tensioner suppression effect. Besides, the heave motion induces a uniform axial vibration of the riser system, while roll and pitch motions excite the riser system to vibrate laterally. Compared with the stress amplitude due to surge and sway motions, the stress amplitude of the riser system due to heave, roll and pitch motions is relatively small but cannot be neglected.

包括钻井立管系统，张紧器和浮动平台的多体系统是海上油气钻探的关键设备。以前的大多数研究都只关注钻井立管系统，而不是多体系统。无法在简化模型中准确分析深水钻井立管系统的机械特性。因此，开发了三维多体分析程序。基于所开发的程序，分析了深水钻井隔水管系统在不同平台运动下的静态和动态特性。结果表明，带张紧器的立管系统的静态位移小于不带张紧器的立管系统，这意味着张紧器可以抑制立管系统的变形。在平台的浪涌和摇摆运动下，由于具有张紧器抑制作用，带有张紧器的立管系统的动态位移也比没有张紧器的立管系统的动态位移小。此外，升沉运动引起立管系统的均匀轴向振动，而横摇和俯仰运动则激发立管系统横向振动。与起伏和摇摆运动引起的应力幅度相比，起伏，横摇和俯仰运动引起的立管系统的应力幅度相对较小，但不能忽略。