基于有限元方法的调距桨桨毂机构强度分析

对受推力、扭力、离心力和螺栓受预紧力联合作用下的某型舰船调距桨完整机构各部件的静强度进行有限元仿真分析;基于ANSYS 12.0软件,考虑完整部件的三维模型以及装配接触关系,对桨毂机构各部件进行有限元建模。有限元分析结果与理论计算和试验结果的对比验证表明,在完整模型和复杂工况下,基于应力应变准则,重点针对如叶根螺栓、曲柄盘和桨毂体等主要受力部件进行分析,更符合实际工程需要。     

沥青混合料温拌技术在公路建设中的应用

综合国力日益增强,我国的建筑设备、建筑材料和建筑技术均获得了很好的发展,在公路建设当中,沥青混合料温拌技术越来越普及,该技术在操作性、减排、降耗方面的优势较为明显。本文简要分析了温拌技术的几大特点,接着分析了沥青混合料温拌技术原理,最后对沥青混合料温拌技术在公路建设中的应用进行了研究。     

Increasing the accuracy of loop detector counts using adaptive neural fuzzy inference system and genetic programming

Loop detectors are devices that are most commonly used for obtaining data at intersections. Multiple detectors are usually required to monitor a location, and this reduces the accuracy of detectors for collecting traffic volumes. The purpose of this paper is to increase the accuracy of loop detector counts using Adaptive Neural Fuzzy Inference System (ANFIS) and Genetic Programming (GP) based on detector volume and occupancy. These methods do not need microscopic analysis and are easy to employ. Four approaches for one intersection are used in a case study. Results show that the models can improve intersection detector counts significantly. Results also show that ANFIS produces more accurate counts compared to regression and GP.     

极地船舶吊舱结构冰载荷计算方法研究

该文根据国外船级社规范,初步探索了一套适用于吊舱结构冰载荷应用分析的计算方法.选取典型吊舱作为计算对象,对两种典型冰况作用条件下的吊舱包结构开展有限元计算工作,验证了本方法的工程适用性.与采用挪威船级社和中国船级社新推荐方法得到的吊舱冰载荷计算结果相比,本方法得到的计算结果没有出现非常离散的情况,差别不大.     

基于无速度传感器的船舶交流推进电机模糊直接转矩控制策略

基于直接转矩控制的普通电力推进船在低速航行时,船舶推进电机的转矩产生明显的周期性振动,为改善此问题,本文将模糊控制逻辑引入到推进电机调速系统中;同时针对电力推进船上速度传感器存在的维修、安装不方便等问题,引入无速度传感器技术。通过Matlab对改进系统进行仿真,结果表明改进后推进电机能够有效的减小转矩脉动,辨识后的转速能有效的跟踪系统的实际转速。     

基于单自由度的桨-轴回转振动特性分析

基于受简谐激励的单自由度系统产生振动的机理,从理论上分析了偏心质量所引起的桨-轴系统回转振动特性,利用幅频特性曲线和相频特性曲线分析该系统稳态响应的动力学特征,探讨系统转速和偏心质量对桨-轴系统回转振动的影响。同时基于Ansys/workbench平台建立了桨-轴系统回转振动模型并进行仿真计算,对理论分析结果进行验证。结果表明,利用单自由度受简谐激励振动模型来分析转子系统回转特性是可靠的、准确的。     

Experimental study on the resistance of a transport ship navigating in level ice

This study investigates the resistance of a transport ship navigating in Arctic waters by conducting a series of model tests in an ice tank at Tianjin University. The laboratory-scale model ship was mounted on a rigid carriage using a one-directional load cell and then towed through an ice sheet at different speeds. We observed the ice-breaking process at different parts of the ship and motion of the ice floes and measured the resistances under different speeds to determine the relationship between the ice-breaking process and the ice resistance. The bending failure at the shoulder area was found to cause maximum resistance. Furthermore, we introduced the analytical method of Lindqvist (1989) for estimating ice resistance and then compared these calculated results with those from our model tests. The results indicate that the calculated total resistances are higher than those we determined in the model tests.     

鹰式装置“万山号”总体设计概述

100kW鹰式波浪能发电装置工程样机“万山号”为一基多体式设计,四个鹰式吸波浮体共享水下附体、能量转换系统及锚泊系统。通过一系列模型试验,获得最优负载。根据模型试验结果,确定了实海况装置的出力参数。为稳定地获得标准电力与试验数据,设计了涵盖蓄能、发电、变电模块、电气监控模块、电源模块、浮态监控模块和岸基模块等多个模块的电气系统。通过锚泊系统计算与分析,确定了锚泊系统的选型参数。     

基于前馈解耦的三相逆变器双环控制器设计

建立了两相同步旋转坐标系下三相逆变器数学模型,构建了其电压电流双环控制方案。为了提高系统的动态响应特性及抗扰能力,在电压外环和电流内环中引入了前馈控制和解耦控制,并由此提出该控制器的设计方法,通过40k VA样机实验表明,该控制器具有良好的动态和稳态性能。     

雪铁龙世嘉车的自动空调故障诊断的教学设计

本文在分析世嘉车自动空调系统电路的前提下对系统电路进行故障设置,研究了该空调系统的故障检测装置的安装方案,设计出有利于加深学生理解空调控制原理和规范检测方法的故障诊断流程。