Review on finite element analysis of welding deformation and residual stress

Welding deformation and residual stress have negative influence on assembly accuracy and service performance. Thermal elastic plastic (TEP) and inherent strain finite element analysis (FEA) methods were used to study this challenge. Basic principle of these two methods was first introduced. The influence of welding process, constraints, solid phase transformation and multi-pass welding on deformation and residual stress was discussed, and computation accuracy and efficiency were summarised. Loading method of inherent strain in inherent strain FEA was analysed, interface element was introduced to simulate effects of the gap on deformation in assembly welding especially for large structures. The future work, including accurately multiscale TEP model, efficiently transient prediction method of large structures, and flexible evaluation software, was planned.     

基于ARM单片机的无线行驶记录仪设计

随着车辆的普及,行驶记录仪在车辆中有广泛应用,介绍了一种基于无线通信的行驶记录仪,解决大型场站车辆读取行车数据的难题。首先介绍了无线行驶记录仪系统的组成,其次重点论述了无线行驶记录仪硬件接口和设计实现形式,并对记录仪软件架构以及控制流程、记录仪管理软件使用方法等内容做了介绍,最后对行驶记录仪使用情况和达到的效果进行了总结。用户反馈表明无线行驶记录仪状态稳定,读取数据方便,管理软件运行可靠,特别适用于大型场站车辆管理使用。     

考虑谐振回路损耗的辅助谐振换流极开关损耗分析

为了精确分析辅助谐振换流极(ARCP)软开关技术对变流设备开关损耗的影响,本文在考虑了谐振回路杂散参数的基础上,对ARCP软开关技术换流过程进行详尽的分析,通过数学推导建立了更为准确的ARCP换流方程和开关损耗模型。最后通过实验验证了换流方程以及ARCP损耗模型的正确性。研究表明,尽管ARCP软开关技术能够基本消除功率器件的开关损耗,但是谐振回路带来了额外的损耗。因此ARCP软开关技术的理想模型不再适用,必须考虑各部分杂散参数对ARCP的影响,并在设计中尽量减小杂散参数,否则很难达到提高效率的目的。     

A disturbance‐decoupled adaptive observer and its application to faulty parameters estimation of a hydraulically driven elevator

In this paper, a disturbance‐decoupled adaptive observer is designed for the joint state‐parameter estimation of a system with unknown disturbance inputs. The proposed Robust Adaptive Observer (RAO) integrates an Unknown Input Observer (UIO) to the parameter estimation process, where the unknown parameters are estimated as extended states of the system. An auxiliary input is added to the UIO in coping with the estimation errors so that the exponential stability and convergence of the observer are guaranteed. The proposed observer is applied to a hydraulically driven elevator for the faulty parameter estimation. The simulation results show the accuracy of the observer and its robustness to both disturbances and measurement noises. Copyright © 2010 John Wiley & Sons, Ltd.     

小型天然气液化厂的安全生产运行管理

阐述了天然气液化厂中,安全生产、持续运行、员工成长3方面的运行管理实践。     

意大利移动市场考察报告

截至2002年4月底,意大利的移动通信用户数已超过5200万,普及率高达88%,用户规模仅次于德国,是欧洲第二大移动通信市场。目前,意大利共有4家GSM移动运营商:TIM,OmnitelVodafone,Wind和Blu,分别占有市场份额的46.7%、34.4%、15.3%和3.6%。意大利的运营商早在1998年就开始了移动互联网业务的市场培育工作,现在,移动互联网业务收入在意大利各运营商的总业务收入中已经占到10%～15%的比例。意大利的3G牌照是通过拍卖的方式颁发,OmnitelVodafone,TIM,Wind,IPSE2000,Wind,和H3G五家运营商获得了3G执照。ReportofStudyTouro     

蓄电池剩余容量预测技术现状及发展

阀控式密封铅酸(VRLA)蓄电池被广泛应用于邮电、电力、交通、军事等诸多领域,在整个系统中发挥着举足轻重的作用。因此,对蓄电池的运行状态,特别是剩余容量(荷电状态)进行在线准确监测(预测)以及有效的管理变得尤为重要。本文以VRLA蓄电池为对象,对国内外蓄电池剩余容量预测技术研究进行了详细的介绍和总结。     

家具教学——原创设计

家具,是一种文化的载体;依据目前国内及国际家具业发展的趋势,家具设计教学更应该提倡家具设计的原创性。