Study on non-linear static behavior of the tendon connector flexjoint

The flexjoint of TLP (Tendon Leg Platform) tendon connector is designed to provide flexibility in rotation while bearing vertical load. The flexjoint is spherical and consists of laminated rubber and metal layers. It's necessary to study the effects of Poisson's ratio and compressibility of the rubber on the flexjoint. Meanwhile, the effect of the number of metal layers is also studied. The 2D axisymmetric nonlinear finite element analysis is carried out to simulate the static behavior of the flexjoint under vertical compression. The Mooney-Rivlin strain energy function is used to describe the constitutive relation of the rubber. The effects of Poisson's ratio of the rubber and the number of metal layers on the vertical compression stiffness and the maximum equivalent stress of the flexjoint are studied. The increase of the number of metal layers will improve the vertical compression stiffness and reduce the maximum equivalent stress. When Poisson's ratio of the rubber material increases from 0.49 to 0.49995, the vertical compression stiffness of the flexjoint increases by 14.7 times. The maximum equivalent stress decreases as the number of metal layers increases and, in this case, the reduction is 115Mpa.