汽车非线性悬架的混沌研究

采用基于实测数据建立的非线性悬架模型,分析了汽车悬架中的非线性弹簧力和阻尼力,对非线性悬架系统的混沌运动进行了研究.在单频正弦路面、拟周期路面以及随机路面激励情况下,仿真计算得到了系统的响应.分析各激励下系统的相轨迹、庞加莱(Poincaré)截面、时间历程曲线、功率谱图及李亚谱诺夫(Lyapunov)指数图,结果表明非线性悬架系统中存在混沌现象.     

燃料电池混合动力汽车动力系统匹配与优化研究

首先,基于中国客车典型循环工况对燃料电池混合动力系统进行匹配计算,确定了电动机、燃料电池发动机和蓄电池的基本参数;然后基于中国客车典型循环工况,建立燃料电池混合动力系统的优化模型,采用序列二次规划算法进行优化,分析了各种参数对整车燃料经济性的影响,包括燃料电池发动机与动力蓄电池之间的功率分配比、SOC的初始值与目标值、变速器传动比及传动比间隔以及主减速比等,为燃料电池混合动力汽车的构型提供指导。     

串联混合动力汽车瞬时优化控制策略研究

建立了基于传动系能量均衡以电池充放电电流为控制变量的系统模型和以等效燃油消耗率最小为目标的优化数学模型。在设定参数条件下,以基于电量平衡的瞬时优化策略对两种常见行驶工况进行了整车仿真。将仿真结果与功率跟随策略的仿真结果进行比较,表明瞬时优化策略能更好地维持车辆行驶过程中电池电量平衡。     

双离合器混合动力轻型客车前向式建模与仿真

根据前向建模的思想建立了基于Matlab/Simulink平台的双离合器混合动力轻型客车前向仿真整车模型、双离合器和ISG电机等主要部件模型,模型既可以用踏板信号作为输入来运行,也可以实现循环工况运行。还制定了动力系统控制策略并建立控制策略模型。根据仿真模型,对其控制策略进行仿真研究,得到整车动力性和燃油经济性等仿真结果,验证了该控制策略的可行性。     

塑性厚壁球壳分析的三维组合格式

本文由修正的增量型兀R变分泛函出发,按照杂交/泥合有限元法、粘塑性理论,采用力学子单元模型,组成了由12节,氛三维六面体过渡元为中介的8一12一20节点三维六面体杂交/况合有限元组合格式。三维厚璧球壳受均匀内压的塑性分析工作说明,采用组合格式并辅以合适数目的高斯积分点,在同等计算精度条件下,计算机开支(CPU)约可节省34%。      

PERFORMANCE ANALYSIS OF HYBRID DS SFH/SSMA SYSTEMS OVER MULTIPATH FADING CHANNELS

ＩｎｔｒｏｄｕｃｔｉｏｎＤｉｒｅｃｔｓｅｑｕｅｎｃｅｓｐｒｅａｄｓｐｅｃｔｒｕｍｍｕｌｔｉｐｌｅａｃｃｅｓｓ（ＤＳ／ＳＳＭＡ）ｓｙｓｔｅｍｃａｎｏｆｆｅｒｈｉｇｈｅｒｃａｐａｃｉｔｙｔｈａｎｆｒｅｑｕｅｎｃｙｈｏｐｐｉｎｇｓｐｒｅａｄｓｐｅｃｔｒｕｍｍｕｌｔｉ－ｐｌｅａｃｃｅｓｓ（ＦＨ／ＳＳＭＡ）ｓｙｓｔｅｍ,ｂｕｔｔｈｅｃａｐａｃｉｔｙｏｆｔｈｅｓｙｓｔｅｍｄｅｐｅｎｄｓｇｒｅａｔｌｙｏｎｔｈｅｐｏｗｅｒｏｆｔｈｅｕｓｅｒ＇ｓｒｅｃｅｉｖｅｄｓｉｇｎａｌｓ,ｔｈａｔｉｓｓｏ－ｃａｌｌｅｄｎｅａ…     

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.     

Parametric vibration and vibration reduction of cables in cable-stayed space latticed structure

Mechanical model and vibration equation of a cable in cable-stayed sparse latticed structure (CSLS) under external axial excitation were founded. Determination of the mass lumps and natural frequencies supplied by the space latticed structure (SLS) was analyzed. Multiple scales method (MSM) was introduced to analyze the characteristics of cable's parametric vibration, and the precise time-integration method (PTIM) was used to solve vibration equation. The vibration behavior of a cable is closely relative to the frequency ratio of the cable and SLS. The cable's parametric vibration caused by the external axial excitation easily occurs if the frequency ratio of the cable and SLS is in a certain range, and the cable's vibration amplitude varies greatly even if the initial disturbance supplied by SLS changes a little. Furthermore, the mechanical model and vibration equation of the composite cable system consisting of main cables and assistant cables were studied. The parametric analysis such as the pre-tension level and arrangement of the assistant cables was carried out. Due to the assistant cables, the single-cable vibration mode can be transferred to the global vibration mode, and the stiffness and damping of the cable system are enhanced. The natural frequencies of the composite cable system with the curve line arrangement of assistant cables are higher than those with the straight-line arrangement and the former is more effective than the latter on the cable's vibration suppression.     

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.     

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。