大跨度自锚式悬索桥钢-STC组合桥面箱形加劲梁抗风性能试验研究

以株洲枫溪大桥为工程背景,采用有限元计算和节段模型试验相结合的方法,研究大跨度自锚式悬索桥STC组合桥面钢箱加劲梁的抗风性能。研究结果表明:钢-STC组合桥面箱形加劲梁结构在-3°、0°及+3°的3种风攻角下,颤振临界风速均远高于桥位处检验风速,设计方案满足颤振稳定性要求,且有较大富余度。成桥状态下的原型断面在+3°攻角下出现了11.1~16.7 m/s与22.7~33.4 m/s两个竖弯涡振区,其中在第二个竖弯涡振区,其峰值振幅0.188 m超过规范允许值。通过对截面进行局部优化后,涡振均在规范允许值以内。节段模型测力风洞试验基于风攻角为-12°至12°范围内变化,研究了加劲梁断面的静力三分力系数的变化规律。大跨度自锚式悬索桥的钢-STC组合桥面宽幅箱形加劲梁的抗风性能试验研究为类似桥梁的设计提供依据和参考。     

长江双涧沙整治工程异常冲刷原因分析及有关施工停歇的思考

2016年汛期长江发生流域性大洪水,南京以下12.5 m深水航道二期工程整治工程因环保要求处于施工停歇期,期间双涧沙头部潜堤工程区域发生异常冲刷。采用水流数学模型和理论分析方法,复演了阶段工程状态相应水情下工程水域流场及流态,揭示工程护底范围内、外发生的异常冲刷原因,取得有关软体排护底设计的深化认识,并探讨因施工停歇要求设计、施工及管理等各方将面临新的工作,可供类似工程建设时参考。     

一种新型同振式矢量水听器的结构设计与性能研究

本文通过分析压电加速度计的幅频特性,设计一种中心位置固定安装的悬挂系统,给出对应的新型同振式矢量水听器的设计方案,并对其性能进行仿真分析.结果表明,中心固定式矢量水听器结构紧凑、安装方便,适合水下小尺寸平台的安装使用,在工作频带内可准确测量声场中声压与质点振速信息.     

Sensitivity analysis and optimisation of suspension bushing using Taguchi method and grey relational analysis

In this paper, a novel method is presented for investigating suspension bushing based on mechanical properties of the bushing, their effective directions, spring stiffness and damping coefficient of bushing. The vehicle vibration model and suspension geometry parameters are used to optimise the vehicle suspension based on multi-body dynamics simulation (ADAMS/CAR) initially. Several experiment tests based on ISO 4128 and ISO 7401 have been performed in one of main Iranian automaker (SAIPA) in order to verify the ADAMS/CAR model. The grey relational analysis based on using Taguchi L27 orthogonal array is used to obtain the optimum suspension. Then the bushing characteristics are optimised considering the indicated method. This method considers a combination of ride comfort and handling qualities of vehicle as objective functions simultaneously. The results of optimum suspension are compared with typical Renault Logan which declares the accuracy and efficiency of this method in optimising suspension bushing.     

Multi-performance analyses and design optimisation of hydro-pneumatic suspension system for an articulated frame-steered vehicle

This study investigates the coupled ride and directional performance characteristics of an articulated frame-steered vehicle (AFSV). A three-dimensional multi-body dynamic model of the vehicle is formulated integrating the hydro-mechanical frame steering and hydro-pneumatic suspension (HPS) systems. The model parameters are obtained from field-measured data acquired for an unsuspended AFSV prototype and a validated scaled HPS model. The HPS is implemented only at the front axle, which supports the driver cabin. The main parameters of the HPS, including the piston area, and flow areas of bleed orifices and check valves, are selected through design sensitivity analyses and optimisation, considering ride vibration, and roll- and yaw-plane stability performance measures. These include the frequency-weighted vertical vibration of the front unit, root-mean-square lateral acceleration during the sustained lateral load transfer ratio period prior to absolute rollover of the rear unit, and yaw-mode oscillation frequency following a lateral perturbation of the vehicle. The results suggested that the implementation of the HPS to the front unit alone could help preserve the directional stability limits compared to the unsuspended prototype vehicle and reduce the ride vibration exposure by nearly 30%. The results of sensitivity analyses revealed that the directional stability performance limits are only slightly affected by the HPS parameters. Further reduction in the ride vibration exposure was attained with the optimal design, irrespective of the payload variations. The vehicle operation at relatively higher speeds, however, would yield greater vibration exposure.     

半主动悬挂机车平稳性和曲线通过动力学性能仿真研究

利用天棚控制原理和SIMPACK动力学软件分别建立二系横向和垂向半主动悬挂机车模型,分析比较了横向、垂向半主动悬挂和被动悬挂的平稳性,以及300 m曲线半径通过时的动力学性能,得出采用半主动悬挂方式可有效地提高机车的平稳性．但同时会使轮对动力学性能恶化。因此有必要对构架结构参数和悬挂系统参数作进一步优化和研究。     

汽车半主动空气悬架的神经网络控制方法

为了提高汽车半主动悬架的控制效果,以空气弹簧压力为控制对象,应用自适应神经网络控制方法,进行了不同路面激励下的半主动空气悬架的车身垂直加速度、悬架动挠度和车轮动载荷的计算机仿真和实验研究,并与被动悬架系统的相应参数进行了对比。发现在白噪声路面和较低频率的正弦路面激励下,半主动空气悬架采用自适应神经网络控制能够明显降低车身垂直加速度、车轮动载荷和悬架动挠度,降低范围为16%~85%,提高了车辆的操纵稳定性,改善了车辆的行驶安全性与乘坐舒适性。     

大跨径悬索桥与斜拉桥钢桥面铺装在竖向荷载静力作用下的力学特性研究

以润扬长江公路大桥为工程背景,研究悬索桥与斜拉桥桥面铺装在竖向荷载静力作用下的力学特性．研究结果表明,在做同类型的桥面铺装设计时,应考虑其桥型整桥力学特点,使桥面铺装设计更加合理。     

自锚式悬索桥主梁面内稳定实用简化计算方法的提出

自锚式悬索桥是一种将主缆直接锚固于加劲梁两端,由主梁直接承受主缆中水平分力的悬索桥。自锚式悬索桥的主梁在外荷作用下,处于压、弯状态,随着外荷载增大,主梁的压力增大到一定值时,可能产生平面内的压、弯失稳,因此,自锚式悬索桥主梁的稳定计算是一个十分重要的问题。主要在弹性支承连续梁临界轴力求解方法的基础上．提出自锚式悬索桥主梁临界轴力的实用简化计算方法。[编者按]     

基于遗传算法的车辆半主动悬架控制系统参数优化

遗传算法(Genetic Algorithm,GA)是一种基于自然群体遗传演化机制的高效优化算法,它能模拟自然界生物进化过程,依据适者生存,优胜劣汰的进化规则,采用人工进化的方式对目标群体进行遗传操作,不断得到更优群体。文章根据遗传算法基本思路,在MATLAB/Simulink中搭建了基于遗传算法的车辆半主动悬架参数优化模型,利用该算法对半主动悬架控制系统参数进行了优化,并对优化结果进行了仿真分析,结果表明,优化后车辆簧载质量加速度均方根值降低31.1%、悬架动挠度均方根值降低11.2%、轮胎动载荷均方根值降低7.1%,车辆平顺性得到提升。