Design Of The Dynamic Fatigue Test Machine For Stretching And Bending Flexible Pipe

With the development of deepwater oil and gas resources in China, a large number of dynamic flexible pipes are needed, and the flexible pipe is indispensable equipment for deepwater oil and gas exploration. Due to the complex structure of the flexible pipe, the current theory and numerical methods can not accurately simulate the mechanical behavior of the pipeline. Especially for the fatigue life of the dynamic flexible pipe, the effective numerical simulation can't be carried out at present, and the fatigue life test of the actual working conditions is usually required. At present, there are only a few foreign countries carrying out the simulation of the fatigue life of the flexible pipe under the working conditions. In recent years, the design and manufacture of flexible pipe has been studied in China, but it has not been simulated the fatigue test under the working conditions. On the one hand, there is no domestic research into a practical flexible pipe, on the other hand, there is no research and development into a practical fatigue testing machine.This paper comprehensively consider flexible pipe bending section under actual working conditions, using computational control the actuator for the real simulation of pipe in the position of heave and roll, realized the accelerated fatigue test of the common flexible pipeline. In order to ensure the fatigue damage and the actual conditions fit, the loading condition of the test specimen is in line with the actual condition of the pipe. This paper based on the design principle of fatigue testing machine, the overall design, basic design, detailed design of the test machine system, and the important design parameters are analyzed. Due to the complex working conditions and large load, the deep sea flexible pipes have higher requirements on the pipeline structure in the design of the testing machine, so adopting frame structure. According to its characteristics, this paper analyzes the structural design of the structure, and creates a three-dimensional model, using the finite element software to analyze the static and fatigue performance of the structure, then the dynamic analysis of the head part of the test machine is carried out by using the dynamic software, and the stress change of the hinge is studied to provide basis for the follow-up test machine connecting bearing and actuator design. Finally, a new type of non-frame fatigue testing machine for small tension bending combined fatigue test is designed in this paper, which is based on the characteristics of flexible pipeline in shallow water. The tester can be more convenient to adjust the distance and replace the head to apply to a variety of different working conditions of the flexible pipe fatigue test, the structure of the testing machine is analyzed and demonstrated, the schematic diagram of the loading mechanism is given, and the finite element simulation and dynamic analysis of the structure of the testing machine are carried out. In this paper, the design and research of the fatigue testing machine system is calculated and analyzed, the results are good to fill the gaps in the domestic, the indicators have reached the international advanced level.