局部应变法敞车侧板模态测试及结构改进

通过某车体侧板结构的模态试验,基于局部应变法测定了侧板的固有频率和振型,通过两种试验结果的相互验证,表明在23.389 Hz频率下,车体侧板的两端,出现了局部二阶振型,局部应变明显增加,在接近该频率的激扰下,存在共振带.通过改进侧板结构刚度,对改进后的新结构按相同的试验方法进行了测试和分析,局部应变明显减小,共振现象消失,证明新设计的侧板结构更合理有效.     

Mental flexibility impairment in drivers with early Alzheimer's disease: A simulator-based study

After memory impairment, one of the most common troubles of early Alzheimer's disease (AD) is the impairment of executive functioning. However, it can have major consequences on daily life, notably on the driving activity. The present study focused on one important executive function involved in driving: mental flexibility; and considered how this impairment can affect driving. Ten patients with early AD were matched with 29 healthy older drivers. All participants were given an evaluation of mental flexibility through neuropsychological tests and an experimental test developed on a static driving simulator. The experiment was divided in two conditions; one without mental flexibility and another condition with a mental flexibility demand. AD patients showed impairments in the neuropsychological tests evaluating mental flexibility. These deficits are linked to the deficits they showed in the driving simulator flexibility tests. This study contributes to the understanding of mental flexibility mechanisms and on their role in driving activity. It also confirms that the driving simulator is a suitable tool to explore cognitive disorders and driving ability.     

不中断交通的梁式桥梁试验与状态评估技术

在不中断交通的条件下建立了运行试验模态分析的模态挠度法。该方法以挠度作为评价桥梁结构承载力的指标,利用来往车辆的激励响应测量数据获得桥梁结构的交通激励试验模态参数,推算出桥梁结构的静挠度,从而评定桥梁结构的承载力。实桥测试表明,该方法可用于桥梁承载力和使用状况评估。     

某船船体模态及振动测试

在振动理论与模态参数识别的理论基础上,对某舰艇整体的模态和振动进行测试,并对其动态特性进行评估,得出对工程实际有应用价值的结论,为船舶使用、预防性修理及其动态设计提供参考依据。     

铁路客车试验模态参数应用分析

运用在振动试验台上和运行工况下模态试验辨识出的几种铁路客车的模态参数,采用综合性能研究方法,以模态参数为基础,分析了各型客车运行性能差异的原因,并提出了完善和改进客车振动性能的措施。     

A new parameter identification methodology for a modal analysis test of a rail vehicle

The validation of vehicle mathematical models is a key part of the virtual acceptance process since it is essential to ensure a precise representation of the reality. The model validation procedure should include validation of stationary but also dynamic tests. However, parameter identification from on-track tests is a challenging task due to the non-controlled excitation and the great variability of the test results. Thus, an alternative solution by means of a vehicle modal analysis is proposed, developing a parameter identification methodology for dynamic vehicle model parameters. This methodology calculates estimated values of the vehicle model parameters that have an influence on the excited vehicle vibration modes. Moreover, a new criterion for taking into account the effect of the measurement uncertainties on the selection process of the vehicle parameters is developed. Finally, experimental results show that not only estimations of the suspension stiffness parameters can be obtained, but damping values and structural frequencies from the vehicle bodies can also be estimated.     

客车转向架抗侧滚扭杆装置特性分析

阐述了客车转向架安装抗侧滚扭杆装置的必要性 ,介绍了抗侧滚扭杆装置的结构和功能 ,建立了抗侧滚扭杆装置的力学模型 ,分析和计算了该装置对倾覆系数、柔度系数等性能参数的影响     

GPS在移动机器人导航定位系统中的应用

为了获得移动机器人定位数据的真实性，减少各种随机误差对定位精度的影响，通过运动载体当前统计模型，取位置作为观测量建立移动机器人动态定位模型，同时针对传统卡尔曼滤波的不足进行了分析，提出自适应卡尔曼滤波算法，该算法始终保持噪声模型接近于真实模型，从而较好地解决了GPS动态定位中状态噪声与观测噪声建模不准确和时变问题，在此基础上，通过模拟噪声和轨迹曲线，进行了仿真，结果显示效果显著。     

TBM掘进模态综合实验平台升级改造研究

为建立全断面岩石隧道掘进机刀盘不同位置滚刀载荷分布规律，防止TBM滚刀及刀座频繁过载失效，通过对TBM掘进模态综合实验平台升级改造，研发了单把滚刀载荷测试方法，实现了单刃滚刀、中心双联滚刀以及不同规格滚刀载荷的直接获取； 开发了滚刀载荷和转速监测系统，实现了滚刀载荷和转速数据的实时采集和无线传输； 制造了可安装不同规格滚刀、刀间距和刀高差可调的多功能刀盘，实现了刀盘刀具多种方式布置。TBM掘进模态综合实验平台的升级改造为TBM刀盘不同位置滚刀载荷分布规律、刀盘刀具布置等滚刀破岩理论的研究提供了实验工具，为TBM滚刀载荷实时监测提供了新方法。     

基于灵敏度分析的轿车车身质量优化研究

以某型轿车为例,建立车身有限元分析模型,对模型进行了试验验证。综合考虑零件厚度对车身质量与刚度的影响,利用灵敏度分析方法确定优化设计变量。以白车身质量最小为目标函数,在保证车身刚度和模态性能的前提下,进行车身质量优化。在车身质量减轻了6.25%的同时,车身刚度和主要模态频率也获得了不同程度的提高。