【作者】 洪俊；

【导师】 芮筱亭；

【作者基本信息】 南京理工大学 ， 工程力学， 2007， 博士

【摘要】 散粒体系统的动力学特性研究是许多领域关心的课题。本文以发射装药发射安全性大课题为背景，比较系统的研究了散粒体系统的运动、堆积以及部分粒子挤压破碎的动力学现象。包括：采用离散单元法数值仿真了散粒体系统动力学行为，并用空间接触识别算法，提高了散粒体系统的接触识别效率；采用几何构建技术获得球形粒子组成的散粒体系统密实堆积结构；将单个粒子的破碎模型应用到散粒体系统中，建立了伴随破碎的散粒体系统动力学仿真方法，并进行了梯形载荷下伴随部分粒子破碎的散粒体系统动力学仿真。采用OpenGL图形库编制了所有数值仿真的后处理程序。针对六棱柱发射药粒组成的发射药床，进行了物理和数值仿真，两者仿真结果基本一致。研究结果对发射装药发射安全性课题提供了理论和实验基础。数值仿真包括：建立了发射药粒的破碎模型，对发射药粒冲击破碎动力学行为进行了仿真研究；采用动力学技术获得发射药床的密实堆积结构；将建立的发射药粒破碎模型和伴随破碎的散粒体动力学仿真方法应用到发射药床的挤压破碎数值仿真过程中，通过跟踪每一个药粒典型时刻运动破碎情况，用统计的方法定量获得发射药床破碎程度。物理仿真包括：通过发射药床膛内燃烧与力学环境物理仿真实验获得和真实情况类似的作用于发射药床上的挤压应力；通过发射药床挤压破碎物理仿真实验获得相应挤压应力下的破碎发射药；用破碎发射药进行密闭爆发器实验，测量其p～t曲线后，利用发射药动态活度的定义，通过引入初始动态活度比的概念，建立了准确描述发射药初始燃烧表面积的方法，从而建立了发射药破碎程度的表征方法。更多还原

【Abstract】 Research on dynamic characteristics of Granular system is concerned in many fields.Under the background of launching safety of propellant charge project, movement,accumulation, press and fracture of granular system have been systemically studied.Dynamic characteristics of granular system is simulated by using the Discrete ElementMethod. In order to improve the computational efficiency, contact detection algorithm isused. Dense accumulation structure of granular system which is made up of many spheralparticles is obtained by using geometrical constructive algorithm. First, fracture model ofsingle particle is applied to granular system. Second, simulation method on granularsystem dynamics with fracture phenomenon is set up. At last, this simulation method isused to study the dynamic characteristics of granular system with fracture phenomenon ofpartial particles under ladder loads. All the results of numerical simulations aredynamically showed by the postprocessing programs which are based on OpenGL.Physical and numerical simulations which are aimed at propellant bed which is made up ofmany propellant particles with hexagonal prism shape are done, and the results of twosimulations are basically identical. The study results provide the base of theory andexperiment for propellant safety.Fracture model of propellant particle is set up, and this model is used to study the dynamiccharacteristics of propellant particle’s impulsion and fracture. Dense accumulationstructure of propellant bed which is made up of many propellant particles with hexagonalprism shape is obtained by using dynamic techniques. Fracture model of propellant particleand simulation method on granular system dynamics with fracture phenomenon are appliedto simulate the press and fracture process of propellant bed. According to followingmovement and fracture of each propellant particle at typical time, the fracture degrees ofpropellant bed are obtained by statistical method.The press stress of propellant bed which is the same to real environment is obtained by thephysical simulating experiment of in-bore burning and mechanical environment ofpropellant bed. Through this stress pressing propellant bed, fracture propellant particles areobtained by the physical simulating experiment of the press and fracture of propellant bed.First, the p～t curve of fracture propellant particles is tested by using the experiment ofclosed vessel. Second, on the basis of the definition of dynamic activity of propellantparticle, the method which is used to exactly describe the initial burning surface areas of all the propellant particles is set up by introducing initial dynamic active ratio. At last, thedescribing method of the fracture degrees of propellant bed is set up.更多还原