物伞流固耦合及多体系统动力学研究

发布时间：2018-03-10 09:27

  本文选题：降落伞　切入点：充气过程　出处：《国防科学技术大学》2016年博士论文　论文类型：学位论文

【摘要】：物伞系统是降落伞减速回收技术中的主要研究对象,随着航空航天技术的高速发展,各类新型的减速任务对物伞系统的功能性和适用性提出了更高的要求。典型的物伞系统工作过程需要经历自由飞行、拉直、充气、稳定下落和着陆等多个阶段,其中充气过程最为复杂,是典型的非线性流固耦合问题。除此之外,物伞多体系统飞行过程的动力学特性也会受到降落伞气动力和结构变形的显著影响。因此从多学科耦合的角度开展物伞系统动力学仿真和试验研究是深入了解降落伞工作过程的关键。本文对物伞系统工作过程的流固耦合问题和多体系统动力学问题进行了数值仿真和试验研究,取得了相应的研究成果。(1)研究了基于任意拉格朗日-欧拉(Arbitrary Lagrangian Eulerian,ALE)方法的流固耦合技术。阐述了复杂降落伞结构特点并给出了用于降落伞充气仿真的初始折叠模型参数化建模技术,建立了降落伞柔性织物结构和周围低速不可压缩流场的控制方程,基于ALE描述对控制方程进行离散,引入网格平滑技术控制伞衣结构单元变形过大的问题,采用基于接触碰撞技术的罚函数耦合方法对降落伞结构节点和流体单元进行约束,实现了降落伞充气过程的流固耦合计算。(2)针对低速空投任务中的降落伞有限质量充气问题进行了数值仿真研究。应用ALE流固耦合技术,引入了ALE动网格运动策略,建立了复杂开缝救生伞的有限元模型,数值模拟充气下落过程伞衣外形变化,对比试验结果分析降落伞充气性能,研究伞衣周围流场衍变机理和流固耦合特性,得到伞衣织物结构动力学响应规律,仿真结果为降落伞设计和伞型开发提供理论依据和数据支撑,具有较强的工程应用性。(3)结合风洞试验数据,研究了火星降落伞超声速充气过程动力学特性。基于时空守恒元解元(Conservation Element and Solution Element,CE/SE)方法和结构力学求解方法(Mechanical Solver)建立了流固耦合平台,采用较为成熟的火星科学试验计划(Mars Science Laboratory,MSL)的盘缝带伞-探测器全尺寸模型和缩比尺寸模型,在流固耦合平台下进行无限质量充气过程的仿真计算,对应风洞试验工况下的盘缝带伞充气性能,将仿真结果与NASA试验数据进行对比验证,得到了盘缝带伞伞衣外形变化规律和充气性能参数,分析了火星降落伞的减速阻力特性,结合试验图像研究了前置体对伞衣周围流场特性和激波分布的影响,仿真结果验证了耦合平台对超声速降落伞流固耦合问题的适用性。(4)基于物伞系统多体动力学理论预测了开伞过载对乘员的损伤概率。建立了空投任务中救生伞和乘员载荷的动力学模型。应用有限质量充气的ALE流固耦合方法仿真了不同开伞工况下的开伞过载和吊带张力曲线,背带约束系统和躯干假人模型,对不同高度速度条件下救生伞的开伞动载及乘员损伤概率进行仿真评估,分析救生伞开伞冲击对人体的影响,总结了人体损伤指标,对身体各部位开伞过载冲击作用下的耐受限值进行评估。(5)研究了火星探测任务中物伞多体系统的动力学相似性准则和缩比试验。首先确定相关无量纲参数,推导动力学相似定律,确定地球和火星飞行试验系统的相似性缩放比例并指导地面试验设计,利用飞艇空投平台开展物伞系统缩比试验,获取降落伞和系统弹道参数,结合降落伞稳定下落过程动力学模型和小扰动理论对物伞系统进行飞行力学仿真和稳定性分析,对比结果验证了物伞缩比试验系统的适用性和动力学模型的有效性。(6)对火星探测的进入、减速和着陆(Entry,Descet and Landing,EDL)全过程的飞行弹道进行了集成仿真。分别建立了盘缝带伞-着陆器系统的进入段、拉直、充气和减速着陆段的动力学模型,基于自适应开伞控制方法获取开伞点参数,并对进入和减速过程的全弹道进行关联性研究和仿真。最后基于面向对象设计语言,集成各阶段动力学模块,建立多学科集成仿真框架,对降落伞和着陆器的EDL全过程弹道和开伞过程动力学进行三维视景显示,便于系统优化设计。本文围绕物伞系统减速工作过程的相关耦合动力学问题,研究了物伞系统的流固耦合方法、多体动力学方法和多学科集成仿真技术,并应用于降落伞空投救生、火星EDL过程的物伞动力学分析和试验设计中。论文对于发展航空航天领域的降落伞回收技术具有重要意义和工程价值。
[Abstract]:Parachute system is the main research object of parachute deceleration recovery technology, with the rapid development of aerospace technology, put forward higher requirements of various kinds of new functional tasks of deceleration parachute systems and applicability. The working process of the typical parachute systems need to experience the free flight, straightened, inflatable, multiple stages of stability whereabouts and landing, the inflation process is the most complex, is a typical nonlinear fluid solid coupling problem. In addition, the dynamic characteristics of parachute payload multi-body system during flight will be parachute aerodynamic and structural deformation of the significant effect. So the simulation and test research of parachute system dynamics development from multi subject coupling the key is to understand the perspective of parachute working process. The research of numerical simulation and experiment this paper parachute system process problem of fluid solid coupling and multi body system dynamics, Some results have been achieved. (1) studied based on arbitrary Lagrange Euler (Arbitrary Lagrangian, Eulerian, ALE) method of fluid solid coupling technology. Describes the characteristics of the complex structure of the parachute are given and used for the initial parameters of the simulation model of folded parachute modeling technology, established the control equation of flexible fabric structure and parachute around the low speed incompressible flow, ALE describes the control equation is discretized based on the grid smoothing control canopy structure unit of large deformation problem using penalty function coupling method of contact collision technology based on the structure of node and unit parachute fluid solid coupling constraints, the parachute inflation process flow (calculated. 2) for low velocity airdrop missions in the parachute inflation problem of finite mass numerical simulation was carried out. The application of ALE coupling technique, introduced ALE The mesh movement strategy, established the finite element model of the complex slotted lifesaving umbrella, numerical simulation of canopy shape change inflation falling process, analysis and comparison of the test results of the parachute inflation performance, the flow field around the evolvement mechanism and fluid solid coupling characteristics, obtained canopy fabric structural dynamic response, the simulation results provide a theoretical basis and data support for the parachute design and the umbrella type development, with more strong engineering application. (3) combined with wind tunnel test data, the dynamic characteristics of the supersonic Mars parachute inflation process. Space time conservation element solution (Conservation Element and Solution based on Element, CE/SE) method and structural mechanics method (Mechanical Solver) was established by using fluid solid coupling platform. The test plan of the Mars Science mature (Mars Science Laboratory, MSL) of the disk gap band parachute full size detector model and shrinkage ratio Inch model simulating infinite mass charging process in FSI platform, wind tunnel test conditions corresponding to the disk gap band parachute inflation performance, simulation results and test data of NASA are validated by disk gap band parachute canopy shape variation and aeration parameters, analyzed the deceleration resistance characteristics of Mars the parachute, on the front body effect on canopy flow characteristics around and shock distribution with the test images, the simulation results verify the applicability of the platform coupled fluid solid coupling problem of supersonic parachute. (4) parachute system multi-body dynamics theory to predict the parachute overload damage probability of the occupant. Based on the established dynamics in the rescue parachute airdrop task model and passenger load. The application of limited quality inflatable ALE fluid solid coupling method is simulated in different conditions of the parachute parachute overload and sling tension curve, back Belt restraint system and trunk dummy model, open the umbrella of different height velocity lifesaving umbrella dynamic load and occupant injury probability simulation assessment, analysis of lifesaving parachute impact on the human body, summed up the damage index of the human body, the parts of the body parachute overload under impact tolerance limit (for evaluation. 5) dynamics Study on Mars missions in parachute payload multi-body system similarity criterion and the scaling test. First, determine the relevant dimensionless parameters, derivation of dynamic similarity law, determine the similarity ratio and guide zoom ground test design of earth and Mars flight test system, carry out the parachute system scaling test by airship airdrop platform, get the parachute and system of ballistic parameters, combined with the parachute falling process dynamic model and simulation analysis of small disturbance stability and flight mechanics of parachute system theory, comparison The results verify the validity of the test system than the applicability and dynamic model of the parachute retraction. (6) to enter Mars, deceleration and landing (Entry Descet, and Landing, EDL) flight trajectory of the whole process of the integrated simulation are established. Disk gap band parachute landing system into section, straightening, dynamic model of inflation and deceleration landing parachute, adaptive control method of obtaining opening point based parameters, and related research and Simulation of the whole trajectory entering and deceleration process. Finally, based on the object-oriented design language, the integration stage dynamics module established a multidisciplinary integrated simulation framework for parachute and the lander EDL whole process trajectory and opening process dynamic 3D scene display, which is convenient for the system optimization design. The coupling dynamics of deceleration parachute systems around the working process of parachute systems 鐨勬祦鍥鸿，

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