Mechanical model and mechanical property analysis of fibre-reinforced hybrid composite pipes

Compared to conventional fibre-reinforced composite pipes, fibre-reinforced hybrid composite pipes are more complex and are characterised by the use of hybrid fibres, hybrid matrices, and multiple fibre winding angles. In this study, based on the mechanical model of conventional fibre-reinforced composite pipes, the cross-section division method, the radial pressure on the adjacent layer by spiral wound rope structures, and the calculation method of axial force in each layer were improved. Furthermore, the von Mises stresses in each layer were calculated to discriminate the failure to establish a mechanical model of fibre-reinforced hybrid composite pipes with any number of reinforced layers under axial tension, internal pressure, and external pressure. Experimental data and the finite element method (FEM) were used to verify the reliability of the established model, with the axial tensile mechanical properties analysed based on the established model. The results showed that the large-angle fibres no longer withstood the axial tensile load when the winding angle of the large-angle fibres was greater than 45°. The matrices yielding was much earlier than the fibre breakage. The matrices hybrid methods have a large influence on the axial tensile properties of fibre-reinforced hybrid composite pipes, and improving the material properties of the inner and outer liners can significantly improve the axial tensile properties of fibre-reinforced hybrid composite pipes.     

一种新的伪并行遗传算法在车间调度中的应用研究

提出了一种改进的伪并行遗传算法(Improved Pseudo-Parallel Genetic A lgorithm,简称IPPGA),将改进遗传算法与SGA伪并行操作(采用并行思想,在同一台机器上完成操作),保证了种群多样性,防止局部早熟收敛;改进算法对部分遗传算子做了改进,采用迭代交叉,多父代产生多子代,让多个染色体中优秀基因段组合产生子代,大大加快收敛速度;设定一个最优个体保存序列库,防止最优解的丢失.采用实际算例进行仿真试验,数据表明改进的伪并行遗传算法(IPPGA)较标准遗传算法(SGA)快速、有效.     

基于疲劳性能的沥青混合料组成优化

分析了沥青混合料组成结构对其疲劳性能的影响,采用BP神经网络和遗传算法相结合的方法,以疲劳性能为目标进行了沥青混合料性能优化设计,获得了4.75mm筛孔通过率、0.075mm筛孔通过率、粉胶比、空隙率与疲劳性能之间的关系,为更好地以性能为中心进行沥青混合料设计提供了参考.     

Hybrid model for prediction of bus arrival times at next station

Effective prediction of bus arrival times is important to advanced traveler information systems (ATIS). Here a hybrid model, based on support vector machine (SVM) and Kalman filtering technique, is presented to predict bus arrival times. In the model, the SVM model predicts the baseline travel times on the basic of historical trips occurring data at given time‐of‐day, weather conditions, route segment, the travel times on the current segment, and the latest travel times on the predicted segment; the Kalman filtering‐based dynamic algorithm uses the latest bus arrival information, together with estimated baseline travel times, to predict arrival times at the next point. The predicted bus arrival times are examined by data of bus no. 7 in a satellite town of Dalian in China. Results show that the hybrid model proposed in this paper is feasible and applicable in bus arrival time forecasting area, and generally provides better performance than artificial neural network (ANN)–based methods. Copyright © 2010 John Wiley & Sons, Ltd.     

着陆阶段航空器航迹检测与风险识别方法

进近着陆是整个飞行过程中最易发生危险的阶段.目前着陆阶段的风险识别 只能依靠塔台管制员的目视观察.在飞行员技术不熟练、起降频繁的通用航空飞行训练 中,目视观察很难准确掌握情况,也因此蕴含了巨大的安全风险.利用视频监视航空器着 陆行为,同时提出了一种适合复杂背景下小目标分割算法,从视频中提取航空器着陆航 迹;并以此为基础进一步识别降落过程中的运行风险.通过对多组不同角度的视频监视数 据验证,该算法可在复杂背景下实现航空器着陆航迹的跟踪、落地时刻的判断及危险滑 行航迹的准确识别,对于保障飞行安全具有重要的现实意义.     

自升式可移动钻井船海管登平台技术

鉴于采用常规固定式平台进行浅海海洋石油工程开发周期长、经济门槛高的工程现状,本文创造性地提出采用自升式可移动钻井船并利用海底管道对新发现的构造进行快速开发,实现油气回收,同时考虑项目工期、成本和可操作性要求,以及自升式可移动钻井船水平位移大等难点,首次提出了“刚性立管+软管膨胀弯”的混合海管登平台方案,计算分析了其可行性,并与传统的“动态软管”、“刚性立管膨胀弯”和“软管穿护管”海管登平台等方案进行优缺点对比。该混合海管登平台方案不仅解决钻井船大位移技术挑战,而且利于国内采办,为今后类似边小油气田快速开发提供很好的借鉴作用。     

物流配送车辆路径问题多代竞争遗传算法

针对遗传算法在解决车辆路径问题时效率较低的缺点,将寿命和年龄的概念引入遗传算法,提出了多代竞争遗传算法.每次通过遗传或变异更新一定数量的个体,对于个体按其年龄和寿命决定其是否留在下一代种群中,或终止其生命.通过这种方式,增加了较优秀个体在种群中的存活时间,加大了其繁殖几率和优秀基因被子代个体继承的概率.并应用算法对实际算例进行了测算,取得较满意结果.多代竞争遗传算法对其他优化问题同样适用.     

混合动力城市客车辅助功率单元技术研究

为提高串联式混合动力城市客车的性能,研究了基于柴油机—电励磁发电机的辅助功率单元(APU)技术。综合考虑效率和排放目标,给出了APU参数的确定方法。提出了APU的电压和功率控制策略,并进行了试验验证。     

船舶调距桨控制系统遗传算法的仿真研究

针对调距桨控制系统现状,设计了调距桨控制系统过程模型,提出了基于遗传算法的PID整定方法.仿真结果表明,该方法克服了传统PID难以获得最佳整定效果的缺点,用于调距桨控制系统是有效的.     

两相邻路口的混杂自动机模型与信号协调控制

根据相邻路口间相互关系,利用混杂自动机模型确定路口信号周期单元,利用道路车流运动模型确定2个相邻交通路口的信号延时参数,并提出了一种信号灯优化策略来协调控制方案。在此条件下,寻找相邻交叉路口信号灯在动态交通条件下的最佳轮转次序和最佳绿信比。仿真结果表明,此方法可以有效地协调两相邻路口的红绿灯信号,在一定程度上改善了路段的交通状况。