基于CDEM的脆性材料冲击破碎特性研究与应用 | |
Alternative Title | Research and application of impact crushing characteristics of brittle materials based on CDEM |
刘新明 | |
Thesis Advisor | 冯春 |
2023-05 | |
Degree Grantor | 中国科学院大学 |
Place of Conferral | 北京 |
Subtype | 硕士 |
Degree Discipline | 工程力学 |
Keyword | 连续-非连续 颗粒弹簧元模型 脆性材料 冲击破坏 |
Abstract | 脆性材料的冲击破坏广泛存在于防护工程、岩土工程、航空航天、机械制造等工程领域,研究脆性材料破碎过程的动力响应、破碎块度与能量演化具有重要意义。本文首先对脆性材料冲击破坏过程的数值计算方法展开了研究,提出了一种可用于模拟脆性材料开裂过程的二维颗粒弹簧元方法;接下来针对典型脆性铁矿石进行了系列数值模拟,获得了典型脆性颗粒的破碎分布和能量演化规律;最后基于现场实验和数值模拟对砌体结构的破碎飞散规律进行了研究。主要研究内容与结论如下: (1)构建了可模拟脆性材料由连续变形到破裂的二维颗粒弹簧元数值方法。该方法引入了法向、切向、纯剪和泊松四种类型的弹簧来描述连续介质的力学性质;提出了基于脆断准则和能量释放率准则的混合破坏准则,对材料的破坏状态进行判断。并通过数值案例验证了此方法的可靠性和鲁棒性,可以适用于模拟岩石材料的断裂破坏过程。 (2)基于连续-非连续单元法(CDEM),从破碎块度和能量角度出发,通过对不同形状、不同冲击速度、不同叠加方式下的脆性铁矿石的破碎块度和能量演化规律进行统计分析,得到了典型脆性颗粒的破碎和能量演化规律。 (3)进行了砌体墙在气云爆炸载荷下的冲击破碎实验与数值模拟,从而精确推导出了砌体结构的断裂能参数,获得了砌体结构破碎飞散过程的破碎块度及动力响应基本规律。 |
Other Abstract | The impact failure of brittle materials is widely present in engineering fields such as protective engineering, geotechnical engineering, aerospace, and mechanical manufacturing. The study of dynamic response, fragmentation size, and energy evolution during the fracture process of brittle materials is of great significance. In this study, we first propose a 2D particle-spring method for simulating the cracking process of brittle materials in terms of numerical calculation methods for the impact failure process of brittle materials. Next, a series of simulations are conducted on the typical brittle material iron ore, and the fragmentation and energy evolution laws of typical brittle particles are obtained. Finally, the fragmentation and scattering laws of masonry structures are studied. The main research contents and conclusions are as follows: (1) A 2D particle-spring numerical method capable of simulating the transition from continuous deformation to fracture of brittle materials is constructed. This method introduces four types of springs, namely normal, tangential, pure shear, and Poisson, to describe the mechanical response of continuous media and proposes a mixed failure criterion based on the brittle failure criterion and energy release rate criterion for material failure judgment. The reliability and robustness of the model are demonstrated through numerical examples, which can be applied to simulate the fracture failure process of rock materials. (2) Based on the Continuum–Discontinuum Element Method (CDEM), the fragmentation and energy evolution laws of brittle iron ore particles under different shapes, impact velocities, and superposition methods are statistically analyzed from the perspectives of fragmentation size and energy. The fragmentation and energy evolution laws of typical brittle particles are obtained. (3) Based on the masonry impact experimental platform and the GDEM, the impact fracture experiments of masonry walls under vapor cloud explosion loads and the numerical simulations under equivalent conditions are carried out. This allows for the accurate derivation of the fracture energy parameters of the masonry structure, and the fragmentation size and dynamic response of the masonry structure during the fragmentation and scattering process are obtained. |
Language | 中文 |
Document Type | 学位论文 |
Identifier | http://dspace.imech.ac.cn/handle/311007/92362 |
Collection | 流固耦合系统力学重点实验室 |
Recommended Citation GB/T 7714 | 刘新明. 基于CDEM的脆性材料冲击破碎特性研究与应用[D]. 北京. 中国科学院大学,2023. |
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