论摆线轮的顺利安装

本文指出,在摆线针轮减速器中,只要满足针齿壳内曲线在给定的摆线轮齿廓的第二共轭曲线之外,即可保证两片相错180°的摆线轮在任意位置均能顺利装入针齿壳内,并编制了相应的计算机软件,解决了摆线轮的顺利安装问题.     

车用发动机配气机构运动学和动力学分析

应用配气机构模拟计算软件AVLTYCON，针对某车用发动机配气机构，建立运动学和动力学模型，进行运动学和动力学计算．在此基础上分析了配气机构进排气部分的工作特性，着重从气门升程曲线的丰满系数、凸轮与平面挺柱间接触应力，凸轮与平面挺柱间润滑效果以及气门落座特性等方面进行了分析．在模拟计算的基础上，进行配气机构受力测试，进一步确认了模拟计算的有效性。     

提高CRTSⅡ型轨道板打磨效率的途径

随着CRTSⅡ型轨道板在高铁领域广泛应用,如何提高轨道板生产效率,合理配置轨道板场规模和数量,减少建场投资和各种资源浪费,已成为一个很现实的问题。在京沪高铁施工中,针对以前板场普遍存在的CRTSⅡ型轨道板打磨效率低的问题,通过对毛坯板生产工艺进一步完善,对工装模具设计、制造及监控等环节进一步优化,对数控磨床及其控制软件升级改造,与京津城际相比,大幅提高轨道板打磨效率,进而提高了轨道板生产效率约20%,为今后CRTSⅡ型轨道板规模化生产积累了宝贵的经验。     

Dynamic force profile in hydraulic hybrid vehicles: a numerical investigation

A hybrid hydraulic vehicle (HHV) combines a hydraulic sub-system with the conventional drivetrain in order to improve fuel economy for heavy vehicles. The added hydraulic module manages the storage and release of fluid power necessary to assist the motion of the vehicle. The power collected by a pump/motor (P/M) from the regenerative braking phase is stored in a high-pressure accumulator and then released by the P/M to the driveshaft during the acceleration phase. This technology is effective in significantly improving fuel-economy for heavy-class vehicles with frequent stop-and-go drive schedules. Despite improved fuel economy and higher vehicle acceleration, noise and vibrations are one of the main problems of these vehicles.

The dual function P/Ms are the main source of noise and vibration in a HHV. This study investigates the dynamics of a P/M and particularly the profile and frequency-dependence of the dynamic forces generated by a bent-axis P/M unit. To this end, the fluid dynamics side of the problem has been simplified for investigating the system from a dynamics perspective. A mathematical model of a bent axis P/M has been developed to investigate the cause of vibration and noise in HHVs. The forces are calculated in time and frequency domains. The results of this work can be used to study the vibration response of the chassis and to design effective vibration isolation systems for HHVs.     

Design optimisation of switch rails in railway turnouts

Inspired by a manufacturing process of switch rails for railway turnouts, a method for the optimisation of switch rail profile geometry is presented. The switch rail profile geometry is parameterised with four design variables to define a B-spline curve for the milling tool profile, and two design variables to prescribe the deviation from the nominal vertical path of the milling tool. The optimisation problem is formulated as a multi-objective minimisation problem with objective functions based on the contact pressure and the energy dissipation in the wheel–rail contact. The front of Pareto optimal solutions is determined by applying a genetic type optimisation algorithm. The switch rail profile designs are evaluated by simulations of dynamic train–turnout interaction. It is concluded that the obtained set of Pareto optimal solutions corresponds to a rather small variation in design variables where increased profile height and increased profile shoulder protuberance are preferred for both objectives. The improvement in the objectives comes at the cost of an earlier wheel transition to the switch rail and thus increased vertical loading at a thinner rail cross-section. The performance of the optimised geometry is evaluated using a set of 120 measured wheel profiles, and it is shown that the optimised geometry reduces damage also for this large load collective. It is concluded that accurate limits on switch rail loading need to be established to determine the feasible design space for switch rail geometry optimisation.     

桩身完整性类别判定的研究

超声波检测技术是近年来发展非常迅速的一种新的无损检测技术。对于桩身完整性类别的判定目前有明确的行业标准规定。通过工程实例,就如何准确评定桩基的质量等级进行了进一步分析和研究。     

浅谈客车地板骨架的降重设计

通过对客车骨架进行有限元分析,给出了地板骨架各部位受力情况,根据受力情况对各部位骨架型材壁厚进行重新调整,从而达到应力不变质量变轻的目的.     

一种基于高阶谱特征的舰船目标识别方法

基于高分辨距离像(HRRP)的舰船目标识别问题,提出了一种基于高阶谱特征的舰船目标识别方法。在对舰船目标HRRP特性分析的基础上,首先利用姿态角进行方位约束筛选,然后通过高阶谱特征结合欧氏距离测度最近邻分类器进行识别匹配。通过10类军民船目标的实测数据进行测试,验证结果表明该方法在舰船目标识别领域具有很好的应用前景。     

打磨深度对在役管道受力状态的影响

在役管道超声波检测前,通常需要对管道表面进行一定量的打磨,以提高声耦合效果.文中基于ANSYS有限元分析和实验验证的方法,对管道在不同打磨程度下的在役受力情况进行了模拟、分析和验证,以研究打磨行为对在役管道受力状态的影响.研究结果表明:将打磨深度控制在一定范围内时,既能满足声耦合需求,又不会对管道的安全运行造成威胁.