The Application Of Material Point Method In The High-speed Impact Of Whipple Shield Structure

In the design of manned spacecraft,it is necessary to consider the protection of spacecraft against space debris impacting,and use dynamic theory to study the integral impact process,which ensuring the rationality of the protective structural design.Whipple protection structure is considered that a convenient and practical space debris protection scheme.Besides the physical verification experiment,the simulation study mainly relies on SPH and improved FEM method.In this paper,the method of researching impacting problem is Material Point Method.The classical Whipple protection structure was analyzed by the C++ program of MPM,amended and strengthened in the material function or other areas,of Sun Qicheng group in Tsinghua university.The diameter of the bullets-ball is 4mm,and the initial velocity is 2km/s and 4km/s respectively.Various characteristics of the whole protective structure with the thickness of 0.5mm,1.5mm,2.0mm and 3.0mm are discussed in-depth exploration.By cross-comparison with the simulation results and experimental results in the literature,the applicability and accuracy of MPM method in studying such problems are verified,and the reliability of the program used in this paper is proved.Then,under the same conditions,the SPH method is used to calculate all of same working condition.And the MPM method,which be proved,is superior to the SPH method in calculation efficiency.Finally,the basic steps and methods of the MPM method in studying such problems are comprehensively discussed,and the feasibility of the MPM method in providing more in-depth study of the mechanical problems under high-speed impact is provided.The material point method has been proved to be practical in all aspects of the problems studied in this paper.it can be concluded that under the condition of same bullet`s diameter in lower initial velocity,the damage effect caused by bullet is greater than the debris cloud,and correlation with thickness of the Whipple plate is small.When the velocity reaches a certain degree,the relationship between the damage effect of bulkhead plate and the thickness of the Whipple plate is enhanced,that is to say that the increased thickness makes the debris cloud more obvious and the damage area of bulkhead plate more obvious.At the same time,the development direction of the next MPM method can be observed.