上海自然博物馆基坑地下连续墙变形研究

新建上海自然博物馆基坑工程为深大异形坑中坑工程,周围环境复杂,施工风险大.利用三维有限元模拟方法,计算内外坑开挖过程中外坑地下连续墙的变形,选取模型中内外坑地下连续墙5种不同间距处的计算结果与现场监测数据对比,得出内外坑连续墙间距小于20m时外坑连续墙最大水平位移随内外坑间距增大而增大,但当内外坑地连墙间距大于20m时,内外坑地连墙间距变化对外坑连续墙最大水平位移影响不大;该工程坑中坑内坑开挖对外坑地连墙水平变形影响较小.     

基于模糊物元的台湾海峡客货滚装船船型经济论证

在两岸关系不断稳定发展的情况下,台湾海峡客货滚装运输具有良好的发展机遇和潜力。针对多准则、多目标的台湾海峡客货滚装船型经济论证问题,以模糊物元理论为基础,构建了基于模糊物元的船型论证方法和模型,并结合实际进行实证研究。实证算例分析结果表明:应用模糊物元理论进行台湾海峡滚装船型论证决策是可行的,此论证方法将定性与定量分析有机结合,方法非常实用,计算比较简便,论证结论客观、合理。     

基于DOE与遗传算法相结合的共轨柴油机喷射参数优化

将DOE与遗传算法相结合对共轨柴油机喷射参数进行优化,并对优化方案进行了燃烧分析和试验验证。针对某型共轨柴油机,利用DOE设计了77种共轨柴油机喷射参数技术方案,再以响应面近似模型技术构造优化目标函数,利用遗传算法对该近似模型进行寻优。试验结果证明优化后柴油机油耗降低5%,NOx降低10%,碳烟降低18%。     

Computational fluid dynamics (CFD) prediction of bank effects including verification and validation

Restricted waters impose significant effects on ship navigation. In particular, with the presence of a side bank in the vicinity of the hull, the flow is greatly complicated. Additional hydrodynamic forces and moments act on the hull, thus changing the ship's maneuverability. In this paper, computational fluid dynamics methods are utilized for investigating the bank effects on a tanker hull. The tanker moves straight ahead at a low speed in two canals, characterized by surface piercing and sloping banks. For varying water depth and ship-to-bank distance, the sinkage and trim, as well as the viscous hydrodynamic forces on the hull, are predicted by a steady state Reynolds averaged Navier–Stokes solver with the double model approximation to simulate the flat free surface. A potential flow method is also applied to evaluate the effect of waves and viscosity on the solutions. The focus is placed on verification and validation based on a grid convergence study and comparisons with experimental data. There is also an exploration of the modeling errors in the numerical method.     

Black-box modeling of ship manoeuvring motion based on feed-forward neural network with Chebyshev orthogonal basis function

Based on polynomial interpolation and approximation theory, a novel feed-forward neural network, the feed-forward neural network with Chebyshev orthogonal basis function, is proposed for black-box modeling of ship manoeuvring motion. The neural model adopts a three-layer structure, in which the hidden layer neurons are activated by a group of Chebyshev orthogonal polynomial activation functions and the other two layers’ neurons use identity mapping as activation functions. Weight update formulas are derived by employing the standard back-propagation (BP) training method. With the simulated 15º/15º zigzag test data as input and calculated values of the hydrodynamic forces and moment as output, the feed-forward neural network with Chebyshev orthogonal basis function and the BP neural network are applied to identify the nonlinear functions in the nonlinear hydrodynamic model of ship manoeuvring motion. With the simulated 20º/20º zigzag test data and 35º turning test data as input, the hydrodynamic forces and moment are predicted by using the identified nonlinear functions. Comparison between the calculated and predicted hydrodynamic forces and moment shows that the feed-forward neural network with Chebyshev orthogonal basis function is superior to the BP neural network in identifying the nonlinear functions of the nonlinear hydrodynamic model of ship manoeuvring motion and is an effective method to conduct the black-box modeling of ship manoeuvring motion.     

天津市双城战略下的交通特征与发展对策

为更好地促进天津市双城空间战略的实现以及城市交通的可持续发展,基于天津市4次居民出行调查,总结改革开放30年来城市交通在出行强度、出行分布、出行结构方面的交通特征与规律。从用地布局和交通模式两方面有针对性地提出了发展对策。用地布局方面,提出提升滨海新区核心区城市职能、注重职住平衡、提倡土地混合利用的发展策略;交通模式方面,针对双城间交通、双城对外交通、双城内部交通提出了具体策略。     

46m对江双体车客渡船

本船为车、客混装的营运性质的双体车客渡船,航行于长江A级航区,航线为张家港市金港镇至双山岛,航行时间5min左右,属第5类中型客船。该船可装载12辆小轿车、1辆标准东风卡车及散客385人;当只载客时,最大载客量可达582人。     

基于对消方法的变频装置试验平台

本文提出了一种变频装置对消的试验平台,属于逆变模块测试技术领域,特别是涉及一种逆变模块试验平台,以两台H桥逆变模块为例,分析设计了对消方法,建立电压电流的基波数学模型,并完成主要电气参数电感值的计算.介绍了基于该方法搭建的变频装置试验平台的组成.采用两组逆变模块对消的方式,在中间电感配置固定的情况下,可以通过调节调制比...     

带有干扰观测器的欠驱动船舶路径跟踪非线性模型预测控制

针对欠驱动船舶提出了一种非线性路径跟踪控制器,使其能够在风、浪、流等环境干扰下驶入预定的航行路径.欠驱动船舶以恒定前进速度航行,并且其合速度与参考轨迹相切.该控制器的设计使用了解析模型预测控制和干扰观测器技术,其中非线性观测器用来估计环境干扰.在最优路径跟踪控制器的作用下,路径跟踪误差渐近收敛到零.数值仿真结果验证了该控制器的有效性.     

丹东地区生态环境的战略地位及其建设途径

丹东地区是辽宁东部山区,是辽宁中部城市群的绿色屏障,是辽宁省水资源、再生能源、林业矿产等项资源主要后盾和林副土特产品的重要生产基地,其生态环境战略地位十分重要。该文提出建设良好生态环境五项措施,即提高森林覆被率,建立多层次的防护体系;选准治理方略,加快小流域治理;依靠科技进步,加快柞蚕场建设;贯彻落实水保法规,依法保护水土资源;结合产业开发,发展区域经济。