轨道车辆柔度系数仿真计算和试验研究

车辆柔度系数是轨道车辆设计过程中的一个重要指标,为了研究车辆柔度系数,文章基于理论计算、仿真分析及台架试验对车辆柔度系数的结果进行了对比分析,对比分析结果可以为轨道车辆设计提供参考作用。     

米轨内燃动车组车体有限元分析及试验验证

针对出口米轨内燃动车组头车车体,采用有限元分析法进行车体静强度仿真分析及模态分析,依据计算结果对车体结构进行优化,并在样车完成试制后开展了车体静强度、模态及平稳性测试,进一步验证了车体设计的安全、可靠及舒适性。     

基于模态参预的激励自由度有效性研究

为研究模态试验激励自由度有效性问题,分3种工况改变激振器输入力相位,对某城际动车组进行静态台架激振器试验,得到输入力及响应加速度信号。根据模态分析理论,利用Test.Lab软件识别车体典型模态参数,并同时得到各阶模态留数矩阵。根据模态参预的定义,得到不同工况下激振力对各阶模态的模态参预。最后根据模态参预矩阵对激励自由度有效性进行判定,同时给出车体1阶垂直、弯曲及车体1阶扭转模态的最佳激励方式,并依据模态参预对模态参数估计的准确性进行简单说明。     

跨坐式单轨车辆头车车体的模态分析

建立了跨坐式单轨车辆头车车体的三维几何模型和有限元模型,并对其进行模态分析,得到了该车体的固有频率和相应的振型.通过对计算结果的分析,指出了设计中可能存在的问题,提出了改进的建议.在低频段的外界激励下,车体的整体振动并不强烈,主要是裙板部分产生较大的振动;为抑制其振动,可采用前、中、后裙板之间进行连接并在后裙板与铝地板...     

铁道车辆刚体模态相似性识别

在目前的动力学研究中,无法对不同参数下的相似刚体模态进行计算机自动识别.基于模糊数学中的最大隶属度原则,对刚体振动模态进行相似性研究,得到了准确度较高的相似模态识别方法,能够对随着参数变化而变化的刚体模态进行自动识别和归类;绘制出了准确的参数-模态曲线,为机车的悬挂系统优化中刚体模态分析的后处理提供了有效的手段.     

基于代数算法的模态柔度灵敏度分析

代数方法解析推导出无阻尼线性系统模态柔度一阶灵敏度的解析表达式,该表达式简洁紧凑,便于编程,而且在计算阶模态柔度的灵敏度时,只需一阶模态信息,具有显著的优点.通过数值模拟算例,并对模态柔度灵敏度进行了参数和模态截断误差分析,着重考查模态柔度对损伤参数的灵敏度.研究结果表明,通过损伤前后模态柔度矩阵的列最大变化值来判定损伤是合理的,而以对角元素变化值进行损伤识别可能出现误判.     

Finite-element model calibration of a railway vehicle based on experimental modal parameters

This article describes the experimental calibration of a three-dimensional numerical model of an Alfa Pendular train vehicle based on modal parameters. The dynamic tests of the carbody and bogie of the vehicle allowed the determination of the frequencies and modal configurations of 13 vibration modes, by applying the data-driven stochastic subspace identification method. In addition, a dynamic characterisation test of the passenger-seat system was also conducted. The calibration of the model was performed using a submodelling/multistep approach involving two phases, the first one focused on the calibration of the model of the bogie under test conditions and the second one focused on the calibration of the complete model of the vehicle. The calibration was performed through an iterative method based on a genetic algorithm and allowed to obtain optimal values of 17 parameters of the numerical model. For the pairing of the vibration modes, real and complex, a recent technique was used based on the calculation of the modal strain energy. The stability of a significant number of parameters considering different initial populations demonstrated the robustness of the algorithm. The comparison of experimental and numerical responses before and after calibration revealed significant improvements in the numerical model and a very good correlation between the responses obtained with the calibrated model and the experimental responses.     

烟囱自振特性的一种较精确分析方法

在工程实践中，高耸烟囱的力学模型大多被简化为离散系统，并使用近似计算的经验公式进行计算，存在着一定的误差。本文中用连续系统力学模型，并选用里茨第二法计算烟囱的自振特性。得到较精确的前三阶固有频率及振型。对不同高度的烟囱进行抗震设计和地震响应分析时，用本文中的特征值进行计算比较精确且简便。     

多跨充液管道的振动特性分析

考虑管道与液体之间的泊松耦合与结合部耦合,推导了低频情况下的充液直管轴向、横向振动传递矩阵与刚性支撑的点距阵.使用传递矩阵法计算两种边界条件下单跨和多跨充液管道的模态频率及模态振型.结果表明,在充液管道振动分析中,流固耦合作用不能忽略,多跨管道系统由于刚性支撑的加入使系统频率增加.     

Modelling and characteristic analysis of tri-axle trucks with hydraulically interconnected suspensions

In this paper, a new hydraulically interconnected suspension (HIS) system is proposed for the implementation of a resistance control for the pitch and bounce modes of tri-axle heavy trucks. A lumped-mass half-truck model is established using the free-body diagram method. The equations of motion of a mechanical and hydraulic coupled system are developed by incorporating the hydraulic strut forces into the mechanical subsystem as externally applied forces. The transfer matrix method (TMM) is used to evaluate the impedance matrix of the hydraulic subsystem consisting of models of fluid pipes, damper valves, accumulators, and three-way junctions. The TMM is further applied to find the quantitative relationships between the hydraulic strut forces and boundary flow of the mechanical–fluid interactive subsystem. The modal analysis method is employed to perform the vibration analysis between the trucks with the conventional suspension and the proposed HIS. Comparison analysis focuses on free vibration with identified eigenvalues and eigenvectors, isolation vibration capacity, and force vibration in terms of the power spectrum density responses. The obtained results show the effectiveness of the proposed HIS system in reducing the pitch motion of sprung mass and simultaneously maintaining the ride comfort. The pitch stiffness is increased while the bounce stiffness is slightly softened. The peak values of sprung mass and wheel hop motions are greatly reduced, and the vibration decay rate of sprung mass is also significantly increased.