动车转向架构架强度分析

以CRH3动车转向架为研究对象,针对动车转向架构架的结构特点和受力特性,建立CRH3动车转向架构架的实体模型,根据TB/T 2368-2005《动力转向架构架强度试验方法》规范确定了构架的载荷工况,并将实体模型导入有限元分析软件ANSYS中对构架进行强度分析。分析结果表明：构架各部位的最大应力值均小于材料的许用应力,构架满足静强度和疲劳强度设计要求。     

基于线路试验的转向架构架疲劳可靠性分析

为提升转向架构架疲劳可靠性分析的准确性,预防等效应力和疲劳强度随时间变化导致的疲劳失效,提出一种基于等效时变动态应力-强度干涉模型的疲劳可靠性分析方法。对预评估转向架构架进行线路试验跟踪测试,采用双参数雨流计数法对实测随机应力-时间历程进行处理,建立用于疲劳可靠性分析的应力谱,并根据Miner法则和疲劳损伤等效原则获得对称循环等效应力。结合连续时间模型和伊藤引理,构建等效应力和疲劳强度的一维布朗运动方程,并以疲劳强度大于等效应力为可靠性判据,提出转向架构架的等效时变动态应力-强度干涉模型,分析构架服役寿命与疲劳可靠度的关系。以某型号转向架构架横梁与吊座连接处为对象,基于实测线路试验数据,验证方法的有效性。结果表明：转向架构架服役1200万公里的疲劳可靠度为74.46%,较传统方法偏于安全。由于考虑了等效应力和疲劳强度的时变性与动态性,使得分析结果更加准确,可为焊接结构的疲劳可靠性评估与结构优化提供参考。     

基于颗粒阻尼的内燃动车组动力包构架多工况减振研究

减少转向架振动有利于控制铁路列车车体平稳,延长结构寿命,对动力包构架的减振研究工作有重要意义。基于颗粒阻尼对某型内燃动力总成(简称动力包)转向架构架进行减振研究,结合有限元方法和模态试验,分析转向架构架的动力学特性,确定颗粒阻尼器安装位置。建立颗粒系统—转向架构架的离散元模型,计算不同阻尼颗粒参数对应的能量耗散值,得出在给定工况下转向架构架最优阻尼颗粒参数。按照计算所得的最优参数,设计、制造、安装颗粒阻尼器,在动力包试验台架上对比分析各工况下转向架构架减振前后测点振动加速度。结果表明,在目标工况下,转向架构架振动幅值在垂向上减少60.7%;在其他档位时,转向架构架振动加速度幅值有15.5%到67.4%不等的减振效果,平均减振效果为49.33%,为转向架构架以及列车其他部件的减振提供了新方法和设计准则。     

基于APDL语言的高速转向架焊接构架优化设计

针对高速列车转向架轻量化问题,采用APDL语言建立某型高速转向架焊接构架的参数化优化设计模型,以高速转向架焊接构架的质量为目标函数,以Goodman疲劳极限线图作为约束条件,对构架结构几何形状进行优化设计,结果表明:优化后构架的质量减少了11.9％,构架应力分布更趋于均匀,减少了应力集中的现象,构架强度满足JISE4207-2004标准的设计要求.     

基于SolidWorks的高速车辆转向架构架研究与试验

设计了一种结构简单、轻量化的高速车辆转向架构架结构,并对其进行有限元分析。确定了转向架构架的技术参数,运用SolidWorks软件对转向架构架进行三维建模,继而对构架进行了模拟仿真应力计算,并完成了强度校核。结果表明:所设计转向架构架,不仅符合转向架构架结构简单、轻量化的设计要求,也满足转向架构架强度要求。     

基于响应曲面法的液力透平叶轮多目标优化设计

建立了基于试验设计理论和响应面近似的液力透平叶轮的优化设计方法。以最高效率、高效区范围及转轮所得扭矩-流量曲线在小流量区的稳定性为目标函数。在使用CFturbo软件建立液力透平叶轮的参数化模型后,先用Plackett-Burman试验设计筛选结构参数,并根据结构参数对目标函数的影响将其划分为三个等级:显著因素、次显著因素和不显著因素;再用正交试验法确定次显著因素的设计中心点;最后由中心复合和Box-Behnken设计及响应面分析确定各级结构参数的最优设计点。该方法以计算流体力学(CFD)的计算结果为基础,共进行40次试验,构造了液力透平叶轮的结构参数与多目标函数的响应面近似模型,分析了结构参数间的交互效应。对最优设计点的液力透平进行了实验研究,试验结果及CFD计算值与响应面近似值吻合,且较优化前的模型在性能上有明显改善,表明基于试验设计和响应面的优化设计方法可用于液力透平叶轮的优化设计。     

实验用CRH3型动车组列车转向架构架设计

动车组转向架的构架,在长期的高速行驶中会产生疲劳磨损,甚至引起构架的失效和断裂,非常容易造成事故。为保证CRH系列动车组列车具有良好的安全性、稳定性以及乘坐舒适性,需要对构架进行分析优化得出符合要求的构架型式。本文对转向架构架进行solidworks三维建模,然后根据《UIC515-4客车转向架结构强度试验方法》对所设计的列车转向架构架进行静强度分析计算与模拟,验证设计结果是否符合设计标准。     

铁道车辆转向架构架强度分析

根据铁道车辆转向架构架所受载荷特点及结构形式,采用有限元仿真分析软件建立该构架的有限元模型,并进行静强度和疲劳强度的计算分析,依据TB/T1335-1996《铁道车辆强度设计及试验鉴定规范》进行构架静强度和疲劳强度的评定。分析结果表明,构架静强度和疲劳强度满足TB/T1335-1996《铁道车辆强度设计及试验鉴定规范》要求。     

二元机翼颤振可靠性研究

机翼气动弹性模型参数一般具有不确定性,为了定量分析参数不确定性对二元机翼颤振可靠度的影响,采用响应面法结合确定性颤振分析对其进行了研究。通过v-g法求解气动弹性运动方程的特征值,获得确定性颤振临界速度,建立描述机翼颤振可靠度的隐式极限状态函数,利用响应面法进行函数拟合。采用验算点法计算颤振可靠度指标,获得设计验算点以及失效概率,分析颤振可靠性灵敏度,从而确定参数变化对机翼颤振的影响程度。最后通过算例分析,得出考虑参数随机性影响的可靠度比确定性分析的可靠度提高了4%,证明本方法切实可行,为机翼结构的颤振分析与优化设计提供理论依据。     

高速动车组构架强度分析

构架作为铁道车辆转向架的主要承载结构,要保证构架具有足够的强度和可靠性。参考《200 km/h及以上速度等级铁道车辆强度设计及试验鉴定暂行规定》(简称《暂规》),以某型高速动车组转向架构架为研究对象,利用有限元软件ANSYS Workbench完成了构架的静强度分析。根据静强度分析结果,利用Goodman-Smith疲劳极限线图对构架的疲劳强度进行了评估。结果表明,构架的静强度和疲劳强度满足规定要求。     

扭转刚度测试方法及对构架疲劳强度影响

根据构架在线路运行中的扭曲状态和标准JIS E 4207：2004《铁路车辆-转向架-转向架构架设计通则》中规定的构架扭转刚度测试方法提出改进的刚度测试方法,新的测试方法简单且实用性较强,误差有效地控制在7%之内。构架根据结构设计形式的不同分为管梁型构架及箱梁型构架。利用新的扭转刚度测试方法分别对管梁型构架及箱梁型构架进行扭转刚度测试,同时理论分析两种类型构架扭转刚度不同的原因。利用ANSYS仿真分析软件对两种类型的转向架构架进行仿真分析,得出：构架扭转刚度的大小主要取决于测量的横截面积及横梁的结构形式,管梁型结构构架扭转刚度小于箱梁型结构构架的扭转刚度;在构架受扭转变形影响较大的区域,如横梁与侧梁的连接位置,由于箱梁型构架扭转模态频率较高,其动应力幅值较管梁型构架要小。     

副车架侧边纵梁耐撞性优化设计

为了对全框式副车架侧边纵梁结构进行耐撞性优化设计,以副车架侧边纵梁结构参数为变量,建立了该结构耐撞性和轻量化优化问题的数学模型。运用方差分析法（ANOVA）选择对副车架侧边纵梁耐撞性和轻量化影响显著的结构因子作为主要设计变量,采用正交试验设计方法进行试验设计;运用LS-dyna软件进行碰撞模拟;根据有限元仿真结果建立了响应面近似模型,并对该近似模型解决该问题的可靠性进行了验证,结果表明,所建立的响应面近似模型适合解决组合优化问题。优化设计后的副车架侧边纵梁能在提高耐撞性能的同时,保持较好的轻量化水平。     

Theoretical research and experimental validation of elastic dynamic load spectra on bogie frame of high-speed train

When a train runs at high speeds, the external exciting frequencies approach the natural frequencies of bogie critical components, thereby inducing strong elastic vibrations. The present international reliability test evaluation standard and design criteria of bogie frames are all based on the quasi-static deformation hypothesis. Structural fatigue damage generated by structural elastic vibrations has not yet been included. In this paper, theoretical research and experimental validation are done on elastic dynamic load spectra on bogie frame of high-speed train. The construction of the load series that correspond to elastic dynamic deformation modes is studied. The simplified form of the load series is obtained. A theory of simplified dynamic load–time histories is then deduced. Measured data from the Beijing–Shanghai Dedicated Passenger Line are introduced to derive the simplified dynamic load–time histories. The simplified dynamic discrete load spectra of bogie frame are established. Based on the damage consistency criterion and a genetic algorithm, damage consistency calibration of the simplified dynamic load spectra is finally performed. The computed result proves that the simplified load series is reasonable. The calibrated damage that corresponds to the elastic dynamic discrete load spectra can cover the actual damage at the operating conditions. The calibrated damage satisfies the safety requirement of damage consistency criterion for bogie frame. This research is helpful for investigating the standardized load spectra of bogie frame of high-speed train.     

暴风雪下塔设备可靠性分析

利用数理统计方法,分析某地区的月平均风速极大值样本,得到其分布参数,进而确定基本风压的分布参数。根据塔设备实际载荷情况,修正了暴风雪情况下工作载荷的力学模型。在塔设备可靠性分析过程的风力计算中引入动态特性系数,更合理地考虑了暴风雪情况下风、雪载荷的不确定性。得到的应力结果符合极值分布,同时也体现了塔设备在暴风雪下风载荷产生的应力的随机性。综合分析风载荷、地震载荷和偏心载荷所产生轴向应力后,建立了可靠性分析的计算方法并进行了实例分析,其结果可为制订塔设备可靠性设计标准作为参考。     

不确定性参数识别的模态区间逆响应面法

结合模态区间分析及响应面的相关理论,提出一种新的不确定性参数识别方法,即模态区间逆响应面法。首先,以有界区间数来量化结构参数的不确定性,通过合理的实验设计确定样本数据;然后,以响应为输入,设计参数为输出,采用逐步回归分析构造设计参数与结构响应的模态区间逆响应面模型,进而直接在模态区间逆响应面模型上进行模态区间运算,即可识别材料参数的变异性区间;最后,采用一组钢板模态实验来验证所提方法的可行性及可靠性。结果表明:所提方法可准确识别钢板材料参数的取值区间,有效地解决多重变量区间运算存在的区间过估计问题,识别过程避免区间迭代优化,具有较高的计算效率。     

Reliability-based design optimization via high order response surface method

To reduce the computational effort of reliability-based design optimization (RBDO), the response surface method (RSM) has been widely used to evaluate reliability constraints. We propose an efficient methodology for solving RBDO problems based on an improved high order response surface method (HORSM) that takes advantage of an efficient sampling method, Hermite polynomials and uncertainty contribution concept to construct a high order response surface function with cross terms for reliability analysis. The sampling method generates supporting points from Gauss-Hermite quadrature points, which can be used to approximate response surface function without cross terms, to identify the highest order of each random variable and to determine the significant variables connected with point estimate method. The cross terms between two significant random variables are added to the response surface function to improve the approximation accuracy. Integrating the nested strategy, the improved HORSM is explored in solving RBDO problems. Additionally, a sampling based reliability sensitivity analysis method is employed to reduce the computational effort further when design variables are distributional parameters of input random variables. The proposed methodology is applied on two test problems to validate its accuracy and efficiency. The proposed methodology is more efficient than first order reliability method based RBDO and Monte Carlo simulation based RBDO, and enables the use of RBDO as a practical design tool.     

Damage identification by response surface based model updating using D-optimal design

Statistical tools, as well as mathematical ones, have been widely adopted and their performance has been shown in different engineering problems where randomicity usually exists. In the realm of engineering, merging statistical analysis into structural evaluation and assessment will be a tendency in the future. As a combination of mathematical and statistical techniques, response surface methodology has been successfully applied to design optimization, response prediction and model validation. This methodology provides explicit functions to represent the relationships between the inputs and outputs of a physical system, which is also a desirable advantage in damage identification. However, so far little research has been carried out in applying the response surface methodology to structural damage identification. This paper presents a damage identification method achieved by response surface based model updating using D-optimal designs. Compared with some common designs constructing response surfaces, D-optimal designs generally require a minimum number of numerical samples and this merit is quite desirable when analysts cannot obtain enough samples. In this study, firstly D-optimal designs are used to establish response surface models for screening out non-significant updating parameters and then first-order response surface models are constructed to substitute for finite element models in predicting the dynamic responses of an intact or damaged physical system. Three case studies of a numerical beam, a tested reinforced concrete frame and a tested full-scale bridge have been used to verify the proposed method. Physical properties such as Young’s modulus and section inertias were chosen as the input features and modal frequency was the only response feature. It has been observed that the proposed method gives enough accuracy in damage prediction of not only the numerical but also the real-world structures with single and multiple damage scenarios, and the first-order response surface models based on the D-optimal criterion are adequate for such damage identification purposes.     

多级载荷累积损伤下结构的动态可靠性分析

在服役环境中的各种不确定性因素及时间因素的共同作用下,结构将产生强度退化与累积损伤,进而严重影响到可靠性。传统的可靠性模型不能很好地反映载荷作用次序与强度退化等因素对可靠性的影响。利用区间理论,考虑应力作用次序不同而导致疲劳损伤的不同非线性演化过程,研究了多级载荷的等效转化问题;为承受多级载荷的强度退化下的结构,建立了动态非概率可靠性预测模型,构造了一种区间模型的动态可靠性分析方法;通过算例对多级载荷累积损伤作用下的结构动态可靠性进行了分析,并验证了方法与模型的有效性。     

基于响应面近似建模方法的换挡电磁阀模型构建

针对换挡开关电磁阀宽温域工况下可靠性不高的技术问题，以较高精度的多场耦合仿真模型实现参数优化为基础，开展换挡开关电磁阀的结构参数优化研究。构建了换挡电磁阀电磁场-结构场-温度场-流场多场耦合有限元仿真模型，通过电磁力测试、温度测试和流量测试分别校验了电磁场模型、温度场和多场耦合模型精度，满足优化设计所需模型精度要求；为了提高优化效率，基于响应面近似建模（RSM）方法完成了宽温域换挡电磁阀电磁力和应力近似模型构建。结果表明构建的电磁力响应面模型R2的值为0.987，最大应力响应面模型的R2值为0.992均大于0.9，近似模型满足设计要求可用于后续换挡电磁阀结构参数优选设计研究。     

Durability evaluation of a composite bogie frame with bow-shaped side beams

In the current study, the static structural safety and durability of two composite bogie frame models were evaluated using a finite element analysis. Prior to evaluation, the in-plane and out-of-plane mechanical properties of the base material were measured. The fatigue property was also measured to evaluate the durability of two composite bogie frames. Based on material data, the static structural safety was examined using the Tsai-Wu failure criterion under ten different loading conditions. Stress combination data were used to evaluate durability of two composite bogie frames. Analysis results indicate that the maximum Tsai-Wu failure indices of the two composite bogie frames under a twisting load were 0.48 and 0.57. Based on the durability evaluation using Goodman diagrams, all combined stress data of the two models were within the endurance limit. In the bogie frames with a side beam height of 50 mm, the side beam bottom area was the most affected region. The joint center area revealed higher mean stress and stress amplitude values in the bogie frames with a side beam height of 150 mm.