火箭撬系统动力学建模和振动载荷研究

Nanjing University of Aeronautics and Astronautics The Graduate School College of Aerospace Engineering
Dynamical Modeling and Research of Vibration Load for Rocket Sled System
December, 2013
承诺书
本人声明所呈交的硕士学位论文是本人在导师指导下 进行的研究工作及取得的研究成果。 除了文中特别加以标注 和致谢的地方外， 论文中不包含其他人已经发表或撰写过的 研究成果， 也不包含为获得南京航空航天大学或其他教育机 构的学位或证书而使用过的材料。 本人授权南京航空航天大学可以将学位论文的全部或 部分内容编入有关数据库进行检索， 可以采用影印、 缩印或 扫描等复制手段保存、汇编学位论文。 （保密的学位论文在解密后适用本承诺书）
本论文的研究工作得到国家自然科学基金项目（编号 11172131、11232007）的资助。 本论文工作在机械结构力学及控制国家重点实验室完成。
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火箭系统动力学建模和振动载荷研究
Abstract
In rocket sled test equipment design, the rapid establishment of rocket sled, accurate analysis of its dynamic characteristics and correct calculation of the vibration load can reduce the development cycle and lower the cost of the system, decreasing the development risk. This thesis developed a simplified dynamic modeling method for rocket sled system. The biggest advantage of the method is that without any specific rocket sled model structure, we can analyze the dynamic characteristics of the system and calculate the rocket sled vibration loads in the basis of just some of the model parameters. Combined with previous studies and project needs, a simplified rocket sled system dynamics model was proposed after the research status of rocket sled dynamics modeling at home and abroad was introduced firstly in this thesis. Then a simplified rocket sled system modeling method was introduced, including the establishment of a simplified dynamic model for different sled structures and calculation for external excitations. For the difficult calculation of track incentive in the modeling process, an approach to calculate the track incentive using random load identification technology was proposed in this paper. Theory of random load identification was studied, and simulation of single-input single-output system was acomplished by using two degrees of freedom system which is similar to the sled model. Finally, for a special rocket sled system in a rocket sled test, we established its simplified dynamic model andcalculated its vibration load. The results were compared with that of the conventional finite element method, verifying that the simplified modeling method of rocket sled system proposed in this paper is feasible. We identified the track incentive through the vibration response calculated by using random load identification method, and compared it with the actual track incentive, confirming the feasibility and reliability of usting random load identification to calculate track incentive. Key Words: Rocket sled system, Simplified modeling, Vibration loads, Tracks incentive, Load identification
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南京航空航天大学硕士学位论文
目
录
第一章 绪论 ..........................................................................................................................................1 1.1 选题背景和意义.......................................................................................................................1 1.2 国内外研究概况.......................................................................................................................2 1.2.1 车轨系统的建模研究概况 ............................................................................................2 1.2.2 火箭撬系统动力学研究概况 ........................................................................................3 1.2.3 火箭撬气动力研究概况 ................................................................................................4 1.3 本文主要研究内容...................................................................................................................4 第二章 火箭撬系统动力学建模...........................................................................................................6 2.1 火箭撬系统动力学建模方法概述 ..........................................................................................6 2.1.1 火箭撬动力学系统描述 ...............................................................................................6 2.1.2 火箭撬车主体动力建模方法概述 ...............................................................................6 2.1.3 火箭撬车所受外激励计算方法概述 ...........................................................................7 2.2 火箭撬车主体建模方法..........................................................................................................8 2.2.1 坐标系定义和自由度选择 ............................................................................................8 2.2.2 火箭撬车主体结构分析 ................................................................................................9 2.2.3 火箭撬车上、下层结构简化为刚体 ..........................................................................10 2.2.4 减震器和滑靴简化方法 .............................................................................................. 11 2.2.5 火箭撬车主体刚体动力学模型建模方法 ..................................................................13 2.3 撬车所受外激励计算方法.....................................................................................................16 2.3.1 撬车所受气动力计算方法 ..........................................................................................16 2.3.2 火箭发动机推力计算方法 ..........................................................................................18 2.3.3 铁轨激励计算方法......................................................................................................18 2.4 本章小结 ................................................................................................................................24 第三章 铁轨激励随机载荷识别方法研究 .........................................................................................26 3.1 随机过程和随机载荷识别理论 .............................................................................................26 3.1.1 随机振动基础..............................................................................................................26 3.1.2 随机载荷识别..............................................................................................................27 3.2 二自由度系统仿真算例.........................................................................................................31 3.2.1 模型频响函数推导......................................................................................................31 3.2.2 随机载荷识别计算及计算结果 ..................................................................................34 3.2.3 结论 ............................................................................................................................37 3.3 本章小结 ................................................................................................................................37 第四章 火箭撬振动载荷计算.............................................................................................................38 4.1 火箭撬系统动力学模型建立 .................................................................................................38