关于加快B＆W662VT2BF-140型主机装置修复工艺程序的探讨

文章主要对B＆W662VT2BF-140型主机装置船上找正交验时,通过采用传统的工艺程序与改进后的工艺程序的比较,说明两种工艺程序的共同点与不同点,以及对修船周期的影响。     

关于高速艇大回转试验的思考

针对近年来围绕高速艇大回转试验出现的分歧意见,分析了进行高速艇大回转试验的必要性,探讨高速艇大回转试验的程序和方法,提出了尽快更新回转试验标准等建议。     

大跨度钢管混凝土拱桥拱肋吊装过程线形调整

工程实例证明,针对大跨度钢管混凝土拱桥拱肋吊装过程中出现的线形调整问题,推导出用最小二乘法对其进行调整的基本方程．提出用解决扣索变原长问题的方法来模拟扣索张拉的实际过程,是正确实用的。     

汽车四轮定位对汽车使用性能的影响

经常检测车轮定位参数,并对它进行适时调整,使其处于合理的范围内,对提高汽车的动力性、操纵稳定性、安全性以及经济性有着重要的意义。     

直接优化解析姿态确定方法

基于惯性系的姿态确定方法是近阶段关于动基座姿态确定问题的热点研究方向,分析了惯性系姿态确定方法的误差源产生机理,发现传统的惯性系首先解析出起始姿态阵,继而通过惯性器件量测输出,更新至当前姿态完成姿态确定,这一更新过程不仅加大了计算量,同时会重新引入器件误差和系统误差。因此,针对这一问题提出了一种基于惯性系的瞬时姿态阵解析姿态确定方法。该方法直接解析出当前时刻的姿态阵,避免姿态更新过程中引入误差,充分发挥了优化解析法的优势,对准精度得到大大提高,并利用仿真和实测数据验证了算法的可行性和有效性。     

轴舵系照光找中工艺流程优化

在轴舵系照光找中方面,虽然传统拉线法设备简单、操作简便,但由于钢丝本身存在挠度,导致测量精度无法保证。随着超长轴系船舶不断增多和船舶建造精度的不断提高,拉线法已不能满足当前船舶建造精度的需要。优化后的轴舵系照光找中工艺采用光学仪器与激光设备代替拉线,所测量的数据更精准、更直观。经多型船实践证明,新的轴舵系照光找中工艺,通过改变过去照光的生产技术,不仅提高船舶建造效率和质量,而且为船厂进一步节约建造成本。     

葛洲坝船闸浮式检修门快速精准对位

葛洲坝船闸浮式检修门(以下简称浮门)是葛洲坝船闸检修设备设施的重要组成部分,在停航期检修中起下游挡水作用,为闸室廊道、下游人字门等检修项目提供无水环境。葛洲坝船闸浮式检修门快速精准对位,是提高葛洲坝船闸停航期检修效率的基础。浮门快速精准对位主要分为3个步骤:浮门门体入槽、门体对位、快速沉浮。通过分析葛洲坝船闸浮式检修门对位现状,从浮门影响因素入手分析研究葛洲坝船闸浮门快速精准对位。     

地下交通转换平台射流通风特性及风流组织方式研究

为探究地下交通转换平台内通风系统的合理布局,采用比尺模型试验和CFD模拟相结合的方法,研究射流风机和通风组织对地下交通转换平台内气流运动的影响。结果表明： 1）当联络通道内风机射流朝向敞开段时,为使风机升压系数Kj最大,630 mm、900 mm、1 120 mm射流风机的布设位置应距离敞开段分别大于40、50、65 m; 2）大口径射流风机具有更大的Kj,但占用的断面空间更大,且射流诱导段更长,应根据联络通道长度和高度合理选择射流风机口径; 3）地下交通转换平台的通风组织不宜采用同侧开启方式,采用对角抽吸方式时,联络通道内的污染物混入比最低、通风效率最高。     

Multi‐objective highway alignment optimization using a genetic algorithm

The available highway alignment optimization algorithms use the total cost as the objective function. This is a single objective optimization process. In this process, travel‐time, vehicle operation accident earthwork land acquisition and pavement construction costs are the basic components of the total cost. This single objective highway alignment optimization process has limited capability in handling the cost components separately. Moreover, this process cannot yield a set of alternative solutions from a single run. This paper presents a multi‐objective approach to overcome these shortcomings. Some of the cost components of highway alignments are conflicting in nature. Minimizing some of them will yield a straighter alignment; whereas, minimizing others would make the alignment circuitous. Therefore, the goal of the multiobjective optimization approach is to handle the trade‐off amongst the highway alignment design objectives and present a set of near optimal solutions. The highway alignment objectives, i.e., cost functions, are not continuous in nature. Hence, a special genetic algorithm based multi‐objective optimization algorithm is suggested The proposed methodology is demonstrated via a case study at the end.     

Optimization of horizontal alignment geometry in road design and reconstruction

This paper presents a general formulation for optimization of horizontal road alignment, composed of tangential segments and circular curves suitably connected with transition curves (clothoids). It consists of a constrained optimization problem where the objective function is given by a line integral along the layout. The integrand is a function representing the cost of the road going through each point and, by considering different costs, a wide range of problems can be included in this formulation. To show it, we apply this methodology to three different situations. The two first cases are related with the design of a new road layout and used to solve a pair of academic examples. The third problem deals with the improvement of a road adapting the old path to current legislation, and it is solved taking as case study the reconstruction project for a regional road (NA-601) in the north of Spain.