Dynamic Characteristics Analysis On Impact Sampling System Of Deep-sea Gravity Piston Sampler

Deep-sea gravity piston sampler is currently used to take long-columnar unconsolidated sediments of one of the basic equipment. In this paper, taking the 30 m gravity piston sampler for research object, integrated use of the theories and methods such as: wave mechanics, soil mechanics, numerical simulation and finite element analysis, the impact system dynamic characteristics and impact sampling performance of gravity piston sampler is deeply analyzed. The impact sampling system wave mechanics model of gravity piston sampler, the influence of impact parameters on the impact sampling performance and the finite element analysis of the impact sampling for deep-sea gravity piston sampler is carried out. The main research works are as follows:Firstly, the literature on the research topic is introduced, then, the importance of impact sampling system dynamic characteristics analysis of gravity piston sampler is explicit. The related research of home and aboard on gravity piston sampler, dynamic of impact system is summarized. The main contents, general structure scheme and innovation points of this dissertation is given.Secondly, the impact sampling system wave mechanics model of deep-sea gravity piston sampler is built and the numerical simulation calculation is carried out. The working principle and structure characteristics of gravity piston sampler is deeply analyzed, the mechanical characteristics of seabed sediments is considered, based on the theory of wave mechanics, the impact sampling system involving a single rod wave mechanics model is established. And based on this model, the numerical calculation method of the impact sampling process of impact sampling system is researched. The numerical simulation program is compiled by use of Matlab, then, the numerical simulation and calculation of the impact sampling for gravity piston sampler is carried out.Thirdly, the impact sampling performance of the deep-sea gravity piston sampler is analyzed. Based on numerical simulation program, to analysis the influence of sampler weight stand, impact height, sampler pipe diameter, and characteristics of seabed sediments, on the impact sampling performance for gravity piston sampler, then, the influence law of impact sampling parameters on the penetration depth, impact sampling efficiency of gravity piston sampler is obtained and the scope of impact parameters is put forward.Finally, the finite element analysis to impact sampling system structure of deep-sea gravity piston sampler is carried out. Based on ANSYS/LS-DYNA, the finite element model of gravity piston sampler impact sampling is established. The finite element analysis and LS-DYNA are used here, to analysis the influence of sediment’s slope, diving angle attack, pipe thickness, sediment types. Then, provide theoretical guidance for structure design, practical application and performance evaluation for deep-sea gravity piston sampler.