桥梁大位移伸缩装置使用浅谈

介绍了目前国内模数式大位移伸缩装置结构及其使用情况,提出大位移伸缩装置选用建议及改进方案;根据国内中梁型钢的材料及断面尺寸,计算多缝支承横梁的合理布置间距;还介绍了梁端运动的主要因素及伸缩装置缝宽计算方法,并结合实例进行说明。     

Parallel processing based on ship maneuvering in identification of interaction force coefficients

The parallel processing based on the free running model test was adopted to predict the interac-tion force coefficients (flow straightening coefficient and wake fraction) of ship maneuvering. And the multi-population genetic algorithm (MPGA) based on real coding that can contemporarily process the data of freerunning model and simulation of ship maneuvering was applied to solve the problem. Accordingly the optimalindividual was obtained using the method of genetic algorithm. The parallel processing of multi-populationsolved the prematurity in the identification for single population, meanwhile, the parallel processing of the dataof ship maneuvering (turning motion and zigzag motion) is an attempt to solve the coefficient drift problem.In order to validate the method, the interaction force coefficients were verified by the procedure and thesecoefficients measured were compared with those ones identified. The maximum error is less than 5%, and theidentification is an effective method.     

深港湾公交中途站设计研究

深港湾公交中途站是一种具有多个服务通道的公交中途站,它可有效减少站内各类车辆之间的相互干扰．减缓车辆排队压力。但目前关于深港湾公交中途站设计的规范、理论尚告阙如,车站设计的科学性、规范性难以保证．该类型中途站的推广与应用也大受影响。基于此,在对现有站设计进行分析的基础之上,提出深港湾公交中途站设计需考虑的若干关键问题,并结合相关理论、规范,对该类公交中途站设计中的主要参数取值进行深入研究．给出取值建议．可为实际工作提供参考．     

基于高阶Prony方法的包装系统模态参数识别

包装系统可看作是多自由度系统,将该系统的暂态响应信号用Prony方法进行拟合,可求出系统各模态参数.介绍了确定系统阶数的方法,并且利用高阶Prony模型和时反信号可在噪声中准确求出各模态参数.模拟结果表明,本方法具有良好的稳健性,可用于识别包装系统的阶数和各模态参数.     

南汇嘴潮滩沉积物粒度特征研究

文中以实测底质采样资料为基础,对南汇嘴沉积物粒度特征进行了分析,并利用Gao&Collins沉积物趋势分析法探讨边滩的沉积物输运趋势。总体上看,样品粒级变化不大,主要以粘土质粉砂、粉砂为主。没冒沙区域由于受到特殊地形以及水流的影响,沉积物以细砂为主;南汇东滩在横向分布上,沉积物粒径逐渐变粗再逐渐变细;南滩受风浪影响,近岸浅滩沉积物颗粒组成较粗,而远岸区域海床颗粒较细。沉积物中值粒径、分选系数和偏度的分布具有一致性,三者相关性较强;浅滩的沉积物粒度特征表现为正偏,分选性较差,分选系数值集中在2左右;南汇嘴区域沉积物运移方向主要是从口外向西输移,汇聚在南汇嘴附近;杭州湾北岸沉积物主要是向东输运,达到芦潮港西侧水域后逐渐转为向南或向南偏东离岸方向运动,对芦潮港附近水下岸坡的冲刷后退起到了一定的影响。     

广义疲劳裂纹扩展模型在单一过载疲劳问题中的应用

对于复杂载荷作用下的船舶及海洋工程结构物,至今仍没有一个统一的疲劳寿命预报模型能够很好地解释载荷次序效应的影响.单峰过载下的疲劳裂纹扩展问题是研究变幅载荷疲劳问题的基础,伴随单峰过载将出现疲劳裂纹扩展迟滞现象.课题组所提出的广义疲劳裂纹扩展模型能够定量地预报出过载迟滞这一现象,通过确定过载参数β的大小,能够有效地衡量出过载迟滞的程度.在此基础上,文章将广义的疲劳裂纹扩展模型进行了进一步的修正,通过引入一个幂指数项,使得模型能够更好地反映出过载后疲劳裂纹扩展速率由迟滞的最低点逐渐恢复到过载前的水平.文中将课题组所发展的广义疲劳裂纹扩展率模型应用于实际的单峰过载疲劳问题中,并引用铝合金D16Cz的单峰过载试验数据与模型预报结果进行了比较,结果发现,经修正的广义疲劳裂纹扩展模型能够更好地反映出单峰过载后的疲劳裂纹扩展情况.     

弹性元件特性参数测试仪的研制

介绍了测试金属波纹管、膜片、膜盒、跳跃膜片等弹性元件特性参数的测试仪.该仪器可以检测集中力-位移、均布力-位移等特性和集中力刚度、均布力刚度、残余变形百分率.实践证明:该仪器精度高、重复性好,是检测弹性元件特性的综合试验仪.     

A universal potential energy function and precise calculations on the molecular spectra

By using a function with a phase factor, a universal analytic potential energy function applied to the interactions between diatoms or molecules is derived and six kinds of potential curves of common shapes are obtained by adjusting the phase factor. The spectroscopic parameters of ten diatomic molecules are calculated by using the potential energy function; as a consequence, all calculation results are in good agreement with experimental data.     

智能算法和物体斜出水水动力参数辨识

提出了一种基于智能技术的新的辨识算法一随机差分群体智能算法,并对约束物体带攻角高速出水的水动力参数进行了辨识,建立了λ22和C,的数学模型.用同一攻角的其它试验数据对辨识的模型进行了验证,结果表明,模型的预测值与观测值相当一致.     

Estimation of longitudinal speed robust to road conditions for ground vehicles

This article seeks to develop a longitudinal vehicle velocity estimator robust to road conditions by employing a tyre model at each corner. Combining the lumped LuGre tyre model and the vehicle kinematics, the tyres internal deflection state is used to gain an accurate estimation. Conventional kinematic-based velocity estimators use acceleration measurements, without correction with the tyre forces. However, this results in inaccurate velocity estimation because of sensor uncertainties which should be handled with another measurement such as tyre forces that depend on unknown road friction. The new Kalman-based observer in this paper addresses this issue by considering tyre nonlinearities with a minimum number of required tyre parameters and the road condition as uncertainty. Longitudinal forces obtained by the unscented Kalman filter on the wheel dynamics is employed as an observation for the Kalman-based velocity estimator at each corner. The stability of the proposed time-varying estimator is investigated and its performance is examined experimentally in several tests and on different road surface frictions. Road experiments and simulation results show the accuracy and robustness of the proposed approach in estimating longitudinal speed for ground vehicles.