兰州大学机构库 >土木工程与力学学院
内置颗粒的弹性球与弹性地面碰撞过程的动力学研究
Alternative TitleDynamic Behavior of Collision Processes Between the Hollow Ball within Some Particles and the Elastic Ground
胡敏
Thesis Advisor慕青松
2010-05-23
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword颗粒介质 弹性球 碰撞 耗散 能量
Abstract本文首次从实验和数值模拟两个方面研究了内置颗粒弹性球从某一高度自由下落与弹性平面发生碰撞的颗粒系统动力学行为。 实验结果给出:乒乓球与地面的碰撞次数随着内装颗粒数目的增加指数衰减,但乒乓球的第一次弹跳高度与内装颗粒数目之间没有清晰的函数关系(第一次弹跳高度十分离散)。进一步分析还发现,无论小米或绿豆,当内装颗粒的总质量相同时,乒乓球的弹跳次数基本相同,依赖关系为弹跳次数随着内装颗粒总质量的增加指数衰减。 在数值模拟结果发现:1)模拟给出了弹性球内颗粒群从杂乱运动到有序运动的自组织演化过程;2)受颗粒初始分布不对称因素的影响,从而在与地面碰撞时系统质心会产生水平线速度且系统整体会产生具有旋转效应的动量矩;3)模拟给出,在内置颗粒数目增大的过程中,球的弹跳次数呈指数衰减,表现为数目较小时,颗粒数目的增加将引起弹跳次数的迅速减小,而当颗粒数目达到一定值后,弹跳次数将基本保持不变,与实验结果相当吻合。系统能量的耗散主要发生在第一次碰撞和第一次碰撞以后的上升阶段,特别是对大颗粒数目系统,在第一次碰撞和第一次碰撞后的上升阶段,基本耗去系统的绝大多数能量。
Other AbstractIn this article, we studied the dynamic behavior of the granular system when the elastic sphere with inner granulars collides with the elastic ground in the two aspects of experiment and numerical simulation. The test results showed that the collision times decreases exponentially with the number of the particles in the table tennis increasing, however, the rebound altitude after the first collision exists no clear relation to the number of the particles in the table tennis. The further analysis presents that whether millets or mung beans, the same mass of the particles in the table tennis always results in the almost same collision times, and that with the mass of the particles in the table tennis increasing, the collision times decreases exponentially. In the numerical simulation results show that: 1) simulation gives self-organization evolution of the particles in the elastic ball from disorder to order; 2) centroid of the system will generate horizontal velocity and the system will produce moment of momentum with effect of rotating because of initial asymmetric distribution of particals in the ball; 3) based on results of simulation, bouncing time of the ball shows exponential decay when the partical number increasing, which is in good agreement with the experimental results. System energy dissipation occurs mainly in the first impact and the rising process after that, in particular, for systems with large number of particles , the first collision and the rising process will consum the most of the energy .
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226061
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
胡敏. 内置颗粒的弹性球与弹性地面碰撞过程的动力学研究[D]. 兰州. 兰州大学,2010.
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