Application of digital image correlation method to in-situ dynamic strain measurement

Application of digital image correlation (DIC) method to determination of in-situ dynamic strain is presented in this study. Firstly, an integrative software is programmed based on the DIC algorithms and point-wise least-squares fitting technique. Then, simulated speckle images are generated to study the computational accuracy of this software. The experimental setup and procedures for measuring in-situ dynamic strain through both DIC and strain gauge are proposed. The DIC results are close to those measured by strain gauge. This fact reveals that DIC is a practical and effective tool for in-situ dynamic strain measurement. Finally, the full-field in-situ dynamic strain of another specimen is measured by DIC, and the overall distribution of the strain in the measurement area is clearly shown.     

船舶电缆自动化敷设系统设计与实现

在船舶电缆敷设过程中,很难借助有效的工装提高劳动效率,低空间的高强度作业存在严重的安全风险。以船舶电缆自动化敷设系统为分析对象,介绍系统组成和系统接口,采用比例积分微分(Proportion Integration Differentiation,PID)算法计算系统行程,通过PROFINET总线完成数据传输,以人机界面(Human Machine Interface,HMI)实现系统性能要求。在风电安装平台上的实际运用表明,该系统可解决造船行业劳动力成本高和安全风险大的问题。     

车挡报警监控记录系统在地铁中的应用

分析了地铁车挡报警监控记录系统的基本功能、组成及原理;论述了该系统在地铁应用中的必要性和重要性;提出了设计优化方案,并对系统后期的发展趋势进行展望.     

基于下游大水位变率的下水式垂直升船机随动技术的设计与实现

下游航道水位变率大,快速适应水位变化的准确停位随动技术,对下水式升船机的传动控制很重要.本文介绍下水式垂直升船机随动控制技术.首先,对控制对象的特性进行分析,描述了系统的速度运行曲线,对位置控制功能进行了研究.然后,搭建试验平台对本控制方案的性能进行了测试,给出了测试的方法和试验结果.实验结果表明本控制系统具有定位精度高、响应速度快等优点,能够适应下游大水位变化率的下水式垂直升船机准确停位要求.     

在时代“大考”中建设人民满意海事——广西海事战“疫”纪实

新冠肺炎疫情发生以来,广西海事局始终把人民群众生命安全和身体健康放在第一位,统筹做好疫情防控与水上交通安全监管。为船员和辖区企业送上贴心服务,在保畅通、保企业复工复产中有为有位;把战斗堡垒筑在疫情防控最前沿,给人民群众带来最安心的守护;在农村疫情防控工作中贡献海事力量,增强村民和全体干部职工的幸福感与归属感,为建设人民满意海事增添了精彩一笔!     

基于有限元分析的五相感应电机参数计算

以自行设计的一台五相感应电机为例,分析了多相感应电动机内部的电磁关系,建立了多相感应电机二维静、瞬态电磁场考虑边界条件的偏微分方程,并在此基础上,对五相感应电动机的暂、稳态电磁场和电机性能进行计算;分别应用场算和路算方法计算了励磁电感,并与设计值进行对比,结果表明本文所用的电磁场计算方法准确有效。     

Personalization method of e-catalog based on user interesting degree

The user interesting degree evaluation index is designed to fulfill the users’ real needs, which includes the user’ attention degree of commodity, hot commodity and preferential commodity. User interesting degree model (UIDM) is constructed to justify the value of user interesting degree; the personalization approach is presented; operations of add and delete nodes (branches) are covered in this paper. The improved e-catalog is more satisfied to users’ needs and wants than the former e-catalog which stands for enterprises, and the improved one can complete the recommendation of related products of enterprises.     

Simulation of mixed gas formation for a spray-wall complex guided LPG direct injection engine

To obtain an ultralean air-fuel ratio and to reduce engine-out NOX and HC emissions induced by the richer mixture near the spark plug, a spray and wall complex guided combustion system has been developed by utilizing the fuel characteristics of LPG. The new combustion system configuration is optimized by using a commercial CFD code, FIRE V2013, and the reliability of the system has been experimentally demonstrated by Plane Laser-Induced Fluorescence (PLIF). The mixture formation in the new combustion system under part load (2,000 rpm) is numerically simulated. With an injection timing of 40°CA BTDC, the LPG spray which is injected from two upper holes, reaches the ignition point, and the other part of the LPG spray which is injected from the bottom hole, is directed to the ignition point through the vertical vortices at the same time. At the ignition timing of about 20°CA BTDC, the two-part mixtures have been shown to form a stable and richer stratified mixture around the ignition point, and the maximum global air-fuel ratio reaches to 60: 1.     

小直径盾构施工中管片纵向应力监测研究

为了探索小直径盾构法隧道在施工过程中管片纵向应力的变化规律,对北京槐房再生水厂污水隧道管片纵向应力进行了现场监测:将第976环、第1 054环管片分别设为第1和第2监测断面,2监测断面各预埋5个纵向应力计,各监测断面从本监测断面管片安装后即开始监测,当盾构掘进至第1 129环时停止监测。研究表明:1)在管片离开盾尾50环后,其纵向应力波动值小于管片拼装期间应力值的5%。2)在盾构掘进期间,管片距离盾构越远,其纵向压应力值越小。3)在管片拼装期间,管片距离盾构越远,其纵向压应力经历了先增大后减小的过程。4)管片距离盾构108环后,该管片纵向压应力趋近于0.2~0.3 MPa。5)随着盾构推进,管片纵向应力经历了4个阶段的变化过程,即周期性剧烈波动阶段—动态稳定阶段—逐渐衰减阶段—趋于稳定阶段。     

A new model for temporal–spatial stochastic analysis of vehicle–track coupled systems

The vehicle–track coupled system has a random nature in the time–space domain. This paper proposes a computational model to analyse the temporal–spatial stochastic vibrations of vehicle–track systems, where the vehicle–track system is divided into a vehicle subsystem, track subsystem, and interfacial subsystem between the wheel and rail. In this model, the time-varying randomicity of dynamical parameters of the vehicle system, correlation, and randomness of the track structural parameters in the time–space joint dimensions, and randomness of the track random irregularities are considered. A probability dimension-reduction method was used to randomly combine different random variables. Furthermore, the probability density evolution method was applied to solve the delivery problem of probabilities between excitation inputs and response outputs. The temporal–spatial stochastic vibrations of the vehicle–track system with different coefficients of variation were studied, in which we assumed that the dynamic parameters obeyed the normal distribution, and the stochastic simulation method of the track random irregularities is probed into. The calculated results from this model are consistent with the actual measured results and physical conceptions. Thus, the temporal–spatial stochastic evolutionary mechanism can be explored, and the limits of dynamic indices can be formulated by using this developed model.