Design And Analysis Of Marine Flexible Riser Fatigue Testing Machine

On the growing demand for oil resources in the circumstances, people are eyeing Ocean. There are three main ways of transportation of ocean oil and gas resources, which is container transport, pipeline transport, container, pipeline transport mixed. At present most countries in the world are using pipeline transport as the main mode of transportation of oil and gas. And pipeline can be divided into two categories, namely, rigid pipe with the flexible pipe. Flexible pipe has many advantages compared with rigid pipe, for example it is yielding easily, recycled, good economic performance and more adapted to the marine environment than rigid pipe.The marine flexible riser are loaded under cyclic stress and behavior much more axial tensile stress and transverse bending stress. Constant cyclic stress will make the pipe arise fatigue failure and affect the service life. Numerical and analytical method is available in flexible riser design, but it need to be verified through the experiment method and the correctness of the results.The main work of this paper is design a kind of testing machine, through the study of the combination of stretch bending experiment of flexible riser, make the riser to carry on the combination of bending and stretching with movement. Through the testing machine to obtain the test result of reliability and final result of the internal structure of the riser under regulation cycle times. This paper carry out the machine structure design based on the principle of flexible riser fatigue test, this structure is horizontal structure, through the tensile side provide tension and swinging end bending moment to simulate flexible riser working environment. Then using finite element software to take static analysis of the main structure of test machine in order to verify the structural strength, and calculate the life of test machine under the largest operating conditions. Established the model of test machine and flexible riser and analyzed the interference problem, the movement of the hydraulic cylinder and the pipe through the multi-body dynamics software. And studied the balance of the machine by using the method of linear independence vector. Finally studied the dynamic characteristics of testing machine, and determined the natural frequency and mode shape of the test machine. Then worked out the dynamic response under the condition of harmonic load.