Kinematics And Dynamics Analysis Of PLS On Semi-submersible Platform

This article is intended for the PLS which is working on the semisubmersible drillingplatform with the super-size and large flexibility and considered the effect of the elasticdeformation and mechanical vibration on the kinematic accuracy because of the gravity andintegrated force. The dynamics model of the mechanism is established by using thekineto-elastodynamics theory base on kinematics analysis. And we get the real motion of themechanism by solving this model. The main works and the results of the research can besummarized by the following several aspects:Establishing the kinematics model of PLS by using the closed-loop vector equation. Gettingthe variation of the motion parameters with time. Establishing dynamics model of PLS byusing the Lagrange equation. Getting the variation of hydraulic pressure which is providedby the hydraulic cylinder with time. Studying the kinematics and dynamics of themechanism and optimizing the rigid motion. Optimizing the motion of the mechanism bymaking the controling force continuously.Establishing the motion differential equation by using the kineto-elastodynamics theory.Getting the mass matrix and stiffness matrix from the equation and calculating theeigenvalues and eigenvectors. Then getting the each step of the natural frequency and modeof vibration which is changing over time. Choosing the most optimal solution of themechanism’s section, the natural frequencies are improved. Verifying the accuracy of thenumerical analysis by using the model analysis which is based on ANSYS. And also got theeach steps of the vibration diagram. Using the mode superposition method to solve thedifferential equation, getting the real moving trace of the mechanism. And verifying thenecessity of the KED analysis.Analyzing the integrated force on the PLS which is working on the semisubmersible drillingplatform. By using the improved plane wave method to solve the wave loads on the floatingcylinder arrays, we get the motion of mechanism with the action of the wave loads. Then wecan get the inertial force on the PLS which is effected by the ocean wave loads. Combiningthe integrated force on mechanism, we analyze the real motion of PLS.Making the software for the kinematics and dynamics analysis of PLS based on MATLABGUI. Getting the result of the kinematics and dynamics Analysis by inputted the structure size, angular velocity, mass and rotational inertia. Finishing the model analysis and gettingthe result of kineto-elastodynamics analysis by inputted the element length, sectiondimension, elastic modulus and density. The conclusion of this paper has great significancefor the design and development of the drilling equipments on offshore platforms.