曲轴系多柔体动力学仿真分析

使用LMS Virtual.lab软件建立曲轴系多体系统动力学仿真模型,对曲轴系进行刚柔耦合多体动力学仿真,得到周期内曲轴系的动态载荷,为研究主轴承液体动力润滑提供边界条件,并根据仿真过程中的应力分布规律找出曲轴受力的危险部位,为曲轴的优化设计提供参考.     

基于柔性多体动力学的地铁车辆动态行为研究

为了更准确地研究地铁车辆的动态特性,详细考虑了地铁车辆关键零部件的结构弹性,提出一种基于柔性多体动力学的地铁车辆动态行为研究方法。首先,建立地铁车体和构架等关键零部件的有限元模型,然后基于子结构理论及Guyan缩减矩阵法对其进行缩减,并结合多体动力学理论形成最终的地铁车辆刚柔耦合动力学模型,采用该模型研究不同线路条件下的地铁车辆动态特性。同时,建立地铁车辆刚体动力学模型,与上述刚柔耦合模型进行对比,研究结构弹性对地铁车辆动态特性的影响。研究发现：在不同线路激扰条件下,刚柔耦合模型与刚体模型的计算结果有较大差别,考虑结构弹性会增大车体振动和脱轨系数等指标。因此,在对地铁车辆运行安全性和乘坐舒适性进行评估时,应考虑车辆的结构弹性。     

客车空气悬架的建模与K&C特性分析

根据某新型大客车的设计要求,运用刚柔耦合的建模方法对客车关键部件进行了柔性处理,建立了前悬架的刚柔耦合的Adams多体动力学模型,并对悬架系统进行了动力学仿真分析。结合理论分析得出该悬架的K&C(Kinematics&Compliance)特性相关数据,以及悬架在运动过程中的参数变化范围,为后期的调校和生产提供了可靠的理论数据。     

基于刚柔耦合动力学的齿轮传动系统动态特性

为得到齿轮轴系响应的动态特性,从柔体动力学基本理论出发,系统分析了刚柔耦合动力学模型的机理,建立了多级齿轮传动刚柔耦合的虚拟样机。此模型能综合考虑传动轴各方向上的柔性特征、湿式换档离合器动态特性以及齿轮时变啮合力对轴类零件动态响应的影响。仿真结果证明了通过虚拟样机技术获取载荷谱的可行性,可用于轴的疲劳寿命预测以及齿轮箱体的振动研究。     

基于EFEM的5R机械臂刚柔耦合动力学分析

为分析复杂机械系统动力学特性,将系统划分为含有限刚性构件的刚柔耦合系统,基于等效元素集成法,对构件自身的动力学特性进行等效,组建成等效系统。将建模的关键归结为系统中二阶转换张量和相应的三阶转换张量的求解以及系统质量阵的组装,然后,按多柔体动力学的方式建立方程。建立了港口起重机5R机械臂刚柔耦合动力学模型,给出了动力响应曲线,并与刚性解进行了比较。结果表明,采用EFEM方法,动力学方程维数减少,系统质量阵阶数降低,模型建立简单快捷,规范化、程式化,解题效率和精度较高。     

变转速倾转旋翼机多体系统气弹响应分析

基于多体动力学方法建立了考虑机翼/旋翼刚柔耦合的倾转旋翼机过渡状态气弹响应分析模型,通过引入倾转过程旋翼尾迹弯曲影响,修正了直升机旋翼常规动态入流模型.集成非定常动态入流方程与倾转过渡状态的多体动力学方程,建立了倾转旋翼机过渡状态下时域非定常耦合分析模型.以半展长弹性机翼全铰接式倾转旋翼机模型为例,分析了倾转旋翼机倾转过渡状态气弹响应时间历程.数值计算表明:建立的时域模型能够快速有效分析了倾转旋翼机过渡状态的气弹特性,能够捕捉变转速倾转旋翼机的机翼/旋翼间复杂的气弹耦合特性.     

刚柔耦合高弹性筛面运动学与料群透筛分布规律

粘湿动力煤深度筛分是选煤领域的研究热点,传统弹性筛面虽然能解决筛分过程堵孔问题,但在料群冲击作用下易损坏.为此,设计了刚柔耦合高弹性筛面,采用振动测试研究了刚柔耦合高弹性筛面运动学特性与空间运动轨迹,通过高速动态测试与筛分试验研究了粘湿料群的运动行为与透筛分布规律,在此基础上,优化了刚柔耦合高弹性筛面结构.结果 表明:...     

基于刚柔耦合模型的月球车振动特性仿真

为了分析月球车在月表环境下的振动特性,将其作为一个刚柔耦合多体系统,基于三维实体造型和多体动力学分析软件建立了刚柔耦合动力学模型。根据美国国家航空航天局的研究,建立了月球表面位移功率谱数学模型,结合谐波叠加法获得了月表不平度。以六轮月球车样机JLUIV-6为研究对象,通过典型越障工况试验验证了所建模型的可靠性。以月面不平度作为振动激励对所建立的动力学模型进行了仿真,分析了月球车车体的振动响应及振动加速度幅频特性。结果表明,月球车在0.8～1.8Hz处存在明显的共振区域,为月球车系统设计及优化提供了依据。     

基于Romax的重载驱动桥刚柔耦合模型

针对以前重载货车驱动桥研究中建模不完整的问题,利用Romax软件建立了完整的驱动桥刚柔耦合模型,给出了仿真结果。并与非刚柔耦合模型在轴承损伤、轴的变形和模态等方面进行了对比,证明了刚柔耦合模型更加真实有效。为驱动桥研究提供了一种更加有效的新方法。     

含橡胶衬套的后悬架柔性扭力梁结构优化

基于刚柔耦合多体动力学理论,利用相关有限元和多体动力学分析系统Hyper-Works及MSC.Adams,建立包含橡胶衬套且具有刚柔耦合特性的复合扭力梁式后悬架模型。施加与实际受力情况一致的边界条件,依据企业试验标准进行结构强度计算。分析结果表明该扭力梁左右两端的局部应力较大。对该处进行相应结构改进和优化,再次进行仿真计算,发现优化方案较好地改善了扭力梁的应力分布,解决了该处因局部应力过大而导致的后悬架断裂的问题。     

基于小变形的柔性多体系统运动学分析

多体系统中柔性体运动一般分为体参考系的范围运动和变形运动。在多数场合,柔性体的变形运动是较小的,可以用对变形广义坐标线性化的动力学方程描述系统动力学行为。但是,目前通用的一些动力学建模方法用于柔性体动力学建模时,存在过早线性化缺陷,导致最终的动力学方程遗失了一些重要的刚柔耦合项。本文采用非线性变形场描述,计及含有变形广义坐标及其导数的二阶小量项,将这种非线性保留到求出偏速度后,再线性化,建立了柔性     

The bond graph model of planar flexible multibody mechanical systems and its dynamic principle

Toincreasethereliabilityandefficiencyofthedy namicanalysisofflexiblemultibodysystems,differentprocedureshavebeenproposedinpreviousworks[1,2].Buttheseproceduresareonlysuitableforasingleener gydomain,suchasastrictmechanicalone,andcan notdealwiththeproblemsofcomputeraideddynamicanalysisofplanarflexiblemultibodymechanicalsys temscontainingthecouplingofmulti energydomains.Bondgraphs[3]havepotentialapplicationsinanalyzingsuchcomplexsystemsbecauseoftheirabilitytode scribethedynamicsofinteractingsyste…     

Complete geometric nonlinear formulation for rigid-flexible coupling dynamics

A complete geometric nonlinear formulation for rigid-flexible coupling dynamics of a flexible beam undergoing large overall motion was proposed based on virtual work principle, in which all the high-order terms related to coupling deformation were included in dynamic equations. Simulation examples of the flexible beam with prescribed rotation and free rotation were investigated. Numerical results show that the use of the first-order approximation coupling (FOAC) model may lead to a significant error when the flexible beam experiences large deformation or large deformation velocity. However, the correct solutions can always be obtained by using the present complete model. The difference in essence between this model and the FOAC model is revealed. These coupling high-order terms, which are ignored in FOAC model, have a remarkable effect on the dynamic behavior of the flexible body. Therefore, these terms should be included for the rigid-flexible dynamic modeling and analysis of flexible body undergoing motions with high speed. Foundation item: Project(10772113) supported by the National Natural Science Foundation of China     

Rigid-Flexible Coupling Dynamic Analysis of Sub-Launched Vehicle During the Vertical Tube-Exit Stage

During the launching stage,hydrodynamic pressure and adapters’ reaction loads can influence the vehicle’s rigid motion as well as cause its structural vibration,which is a typical rigid-flexible coupling dynamic problem. This paper presents a 2-D rigid-flexible coupling model to calculate the vehicle’s dynamic responses in that period.The vehicle was equivalent to a flexure beam with axial deformation. Hybrid coordinate and modal superposition methods were used to describe its large rigid displacement and small deformation. By the second Lagrange equation,the vehicle centroid’s displacements,rotational angle and modal coordinates were chosen as generalized coordinates and then the vehicle ’s rigid-flexible coupling dynamic equations were obtained. By numerical simulation,the results of vehicle’s motion parameters and transverse internal loads were acquired.The calculation results showed that differences of the vehicle’s motion parameters between the rigid-flexible coupling model and the rigid body assumption are noticeable and the peak magnitude of the vehicle’s transverse internal loads in the rigid-flexible coupling model is higher remarkably than that in the rigid body assumption.     

刚柔耦合系统的输入成形控制

为实现对大范围运动刚柔耦合系统的振动抑制,提出基于一次近似动力学模型的输入成形控制方法.针对中心刚体-柔性旋臂梁系统,在变形位移的描述中计及纵向变形的二次耦合项,建立一次近似动力学模型用于振动控制.考虑到大范围运动刚柔耦合系统中柔性梁有别于结构动力学中定边界梁的模态特性,设计抑制柔性振动的鲁棒多模态输入成形器.仿真结果...     

刚柔耦合二级运动调整系统动力学模型

安装在悬挂馈源舱内的Stewart平台作为馈源位姿精调系统与舱索粗调系统一起构成了大型射电望远镜馈源位姿的二级耦合调整系统．综合柔性悬索系统的非线性有限元结构动力学方程和刚性Stewart平台的多体系统动力学方程，构造了悬索粗调系统与Stewart平台精调系统的刚柔耦合动力学模型，找到了分析动力学耦合问题的有效方法．通过对LT50m缩比模型的仿真分析，模拟了馈源舱对Stewart平台扰动的响应，并由实验进行了验证．     

Multi-Body Dynamics Modeling and Simulation Analysis of a Vehicle Suspension Based on Graph Theory

Multi-body dynamics, relative coordinates and graph theory are combined to analyze the structure of a vehicle suspension. The dynamic equations of the left front suspension system are derived for modeling. First, The pure tire theory model is used as the input criteria of the suspension multibody system dynamic model in order to simulate the suspension K&C characteristics test. Then, it is important to verify the accuracy of this model by comparing and analyzing the experimental data and simulation results. The results show that the model has high precision and can predict the performance of the vehicle. It also provides a new solution for the vehicle dynamic modeling.     

Motion function reliability analysis of a rotating flexible beam with random parameters

The assumed mode method and stochastic response surface method are combined to analyze the motion function reliability of a rotating flexible beam with random parameters. Firstly, based on Lagrange's equations and the assumed mode method, the rigid-flexible coupling dynamic model which takes the coupling term of the deformation in the expression of longitudinal deformation is studied. Then considering the physical and geometrical parameters under randomness, the probability analysis is made by the stochastic response surface method. The rationality and efficiency of the modeling and the method presented are verified by an example. The results demonstrate that the third order stochastic response surface method leads to good precision with acceptable time consumption compared with the Monte Carlo (MC) method, and that the randomness of density has a greater effect on the reliability of the system.     

多体系统动力学方法的对比

针对一个简单的刚弹耦合多体动力学系统，分别求出其运动的解析解、凯恩法解和多体系统传递矩阵法解，并对它们的结果进行了对比。