耙吸挖泥船吊放系统支撑结构设计与强度评估

本文通过对耙吸挖泥船吊放系统的载荷特点及其其与船体连接处的受力情况分析,探讨了有限元法校核连接处结构强度和局部振动性能,总结了工程船此类特殊设备的加强结构设计和计算校核方法。作为耙吸挖泥船作业的重要辅助设备,吊放系统必须安全、可靠,与船体连接有足够的强度和刚度,能满足频繁吊放耙管的需求。研究吊放系统的加强形式和强度校核方法,可为工程船特殊设备的船体加强区域的结构设计提供实用的参考。

一种挖泥船最小能耗工作点计算选取方法

[目的]为了解决挖泥船短排距工况下高能耗的问题,提出一种最小能耗工作点的计算选取方法。[方法]基于前期研究建立的泥泵排压、管道阻力、关键流速和泥泵汽蚀等相关模型,以单方能耗最小为目标,采用施工人员最为熟知并方便控制的泥泵转速为优化变量,运用输送系统最佳流速搜索和多泥泵转速优化相结合的双重优化方法,实现挖泥船多个泵串联最小能耗工作点的计算选取,并以配置有3台不同型号离心泵的“新海狼”号挖泥船在特定工况条件下施工为案例进行算法验证。[结果]结果显示,经所提算法模型优化后的工作点单方能耗比最大产量工作点的单方能耗降低了11.8%。[结论]研究成果的应用能有效弥补已有以施工能力(最大产量)为目标的优化施工方法,为疏浚工程的节能减排工作提供参考。

Novel disturbance compensating dynamic positioning of dredgers based on adaptive backstepping

In order to deal with the dynamic positioning system control problems of dredgers working under strong dredging reaction or harsh environments,an adaptive backstepping method is proposed.Disturbances are estimated and compensated for by the adaptive method without extra sensors on dredging equipment,and the control mechanism is simplified.Adaptive control is used to compensate for the reaction and environmental disturbances on the dredger,so the dredger can maintain the desired position with a minimum error and shock.The proposed adaptive robust controller guarantees the global asymptotic stability of the closed-loop system and rapid position tracking of the dredger.The simulation results show that the proposed controller has superior performance in position tracking and robustness to large disturbances.

Laboratory model study of newly deposited dredger fills using improved multiple-vacuum preloading technique

Problems continue to be encountered concerning the traditional vacuum preloading method in field during the treatment of newly deposited dredger fills.In this paper,an improved multiple-vacuum preloading method was developed to consolidate newly dredger fills that are hydraulically placed in seawater for land reclamation in Lingang Industrial Zone of Tianjin City,China.With this multiplevacuum preloading method,the newly deposited dredger fills could be treated effectively by adopting a novel moisture separator and a rapid improvement technique without sand cushion.A series of model tests was conducted in the laboratory for comparing the results from the multiple-vacuum preloading method and the traditional one.Ten piezometers and settlement plates were installed to measure the variations in excess pore water pressures and moisture content,and vane shear strength was measured at different positions.The testing results indicate that water dischargeetime curves obtained by the traditional vacuum preloading method can be divided into three phases:rapid growth phase,slow growth phase,and steady phase.According to the process of fluid flow concentrated along tiny ripples and building of larger channels inside soils during the whole vacuum loading process,the fluctuations of pore water pressure during each loading step are divided into three phases:steady phase,rapid dissipation phase,and slow dissipation phase.An optimal loading pattern which could have a best treatment effect was proposed for calculating the water discharge and pore water pressure of soil using the improved multiple-vacuum preloading method.For the newly deposited dredger fills at Lingang Industrial Zone of Tianjin City,the best loading step was 20 kPa and the loading of 40-50 k Pa produced the highest drainage consolidation.The measured moisture content and vane shear strength were discussed in terms of the effect of reinforcement,both of which indicate that the multiple-vacuum preloading method has a better treatment effect not only in decreasing the moisture content and increasing the bearing capacity,but also in increasing the process uniformity at different depths of foundation.

Settlement Prediction of Dredger Fill with the Optimal Combination Model

Post-construction settlement has gained increasing attention because it frequently causes engineering problems. A combined model is a commonly used prediction model that overcomes the difficulty of a single model( i. e., cannot reflect various regulations of settlement at some stages or the entire process). In this study,the correlation coefficient,maximum error values,and other values were obtained according to the fitting and predicted results of a single model. The coefficient of variation was then introduced to determine the weight of each model forming the combination. The proposed model was used to fit and predict for settlement and overcome the issue of utilizing a single model while determining the weight. The fitting predictive effect was also analyzed using the settlement fitting precision results. The fitting precision of optimizing the combination model is high. The predicted data of the post-construction settlement are closer to the calculated value of the settlement monitoring data. Moreover,the proposed model has good practicability,does not require the interval data of settlement,and restricts the model number. Thus,this model can be applied in the engineering field.

Experimental Study on Dispersion Coefficient of Dredger Fill in Reclamation Region

In order to satisfy the demand of land use, reclamation engineering has been undertaken in coastal cities for a long time. To study the contaminant transport in the reclamation districts, robust and accurate estimation of dispersion coefficient is essential. In this study, the continuous sodium chloride （NaC1） solution with constant concentration was introduced into the column filled with the dredger fill to get the breakthrough curves （BTCs）. Inverse error function method （IEFM） and CXTFIT program were used for estimating dispersion coefficient. Results showed that the difference between the dispersion coefficients estimated by IEFM and CXTFIT program was slight. The main reason was that the BTC was not strictly linear. IEFM performed poorly in the nonlinear area, while the CXTFIT performed well over the entire BTCs. Moreover, the dispersion coefficient of dredger fill was small. The dispersion property of dredger fill would result in the slow migration of contaminants in the dredger fill.

Research on pore microstructure features for dredger fill based on mercury intrusion method

The material composition and microstructure have a comprehensive influence on geological engineering properties of dredger fill.The porosity of the dredger fill is an important characteristic of microscopic structure.Taken dredger fill from Binhai New Area in Tianjin as research object,the distribution trend of pore is obtained by granularmetric analysis,mineral composition analysis and mercury intrusion method.By discussing the variation regulation of dredger fill in two different kinds of processing methods,certain theoretical basis is provided for evaluating the engineering geological properties of dredger fill.It can be concluded from the test results that after drainage treatment,the porosity decreased and the structure unit changed from the relatively loose state to aggregate state.In certain depth range,the consolidation effect of dredger fill with drainage treatment is better than that without drainage treatment.

绞吸式挖泥船柔性三缆定位系统的应用

绞吸式挖泥船因具有较高的挖泥和卸泥效率而得到广泛的应用。定位系统是绞吸式挖泥船的最关键系统之一,在挖泥施工中起到至关重要的作用。文章即针对定位系统中的柔性三缆定位系统的原理、组成和在实船上的应用进行介绍,并对柔性三缆定位系统应用中存在的问题和发展趋势进行总结和展望。

Resistance of Air Injection Transportation in a Cutter-suction Dredger

Cutter-suction dredger transports slurry through pipeline. But the pipeline is easy to be jammed and frayed because of huge resistance, resulting in limited exertion of dredger and high energy consumption. One of the solutions is air injection transporting, which can reduce the resistance in pipeline. This paper makes research on the relations between pipeline distance and other factors such as slurry concentration, pressure of air injection and transportation distance, by making use of Prof. Aluf Orell＇ s slug model. The test data prove that the key factors are slurry concentration and air volume fraction, and that high slurry concentration and low air volume fraction can reduce more resistance, and such reducing effect becomes weaker with the increase of transportation distance.

大型绞吸挖泥船性能提升研究

在中长周期波浪海况条件下,针对我国早期研制的大型绞吸挖泥船施工适应性差、长排距工程排距受限等难题。本文以“天杉”船为研究对象,通过理论分析、数值模拟、有限元分析计算、实船验证等方法,开展了大型绞吸挖泥船定位系统性能提升、输送系统性能提升、船舶动力系统升级研究,形成了一系列大型绞吸挖泥船性能提升的技术,并成功应用。为我国早期研制的大型绞吸挖泥船的性能改善提供参考。

耙吸船主机负荷控制的分析

为了避免耙吸船推进系统故障,从瓦锡兰LIPS推进控制系统入手,分析总结可能导致推进控制系统产生故障的诱因。通过船舶实践,确定推进系统自动减螺距故障的延展性,结果表明推进系统故障是由异常的传感器信号检测导致。本文分析结果对于采取瓦锡兰推进控制系统的各类船舶具有一定的指导意义。

7000 m^(3)耙吸挖泥船主推进系统集成研究

开展对7000 m^(3)耙吸挖泥船主推进系统方案集成技术的研究,从集成方案设计、船-机-桨匹配、设备选型、设计计算和试验验证等方面,介绍该船主推进系统集成工作。通过对该船主推进系统集成技术的研究,掌握多工况工程船舶集成核心技术,实现船-机-桨匹配设计,可满足多工况使用要求,同时对其他高技术船舶具有一定的借鉴意义。

耙吸挖泥船消能箱关键参数对装舱效果影响的数值分析

消能箱作为泥舱系统的关键设备,直接参与疏浚装舱过程,其出流特性对船舶装舱效果及生产效率有重要影响。以1.50万m 3耙吸挖泥船的消能箱为研究对象,采用流场数值模拟手段,对消能箱主体尺寸、结构形式等影响出流特性的关键参数进行计算分析。结果表明,在一定范围内,消能箱管径越大,消能效果越好,且出流均匀性得到一定程度改善;等截面积条件下,圆形截面消能箱的装舱效果显著优于方形截面的设计;消能箱中部开口指向舱底的速度分量较大,可通过布置水平挡板进行局部优化。该消能箱设计有助于改善疏浚装舱过程中细粉砂的沉积效果,节省装舱时间,减少溢流损失。

某大型绞吸式挖泥船舵系修复方案

文章通过对某大型绞吸式挖泥船在厂修理期间的状况进行研究,分析了导管舵舵杆轴套偏磨严重的现象及其原因,制定了专业的修复方案并完成了修复工程。解决了船舶的零部件磨损等问题,消除了船舶的安全隐患,为其它船舶的类似工程提供了经验。

绞吸式挖泥船绞刀系统液压冲击研究

随着沿海经济的快速发展,绞吸式挖泥船具有广阔的市场,已成为水下开挖输送施工、水域工程治理的主要设备,但是由于液压冲击,绞吸式挖泥船的叶片泵经常发生故障,降低了挖泥船工作效率。对绞吸式挖泥船由于土质不均所引起的液压冲击进行分析研究,并在系统中连接蓄能器。利用三维建模软件AMESim对绞刀系统进行实体建模,模拟实际工况对绞刀马达加载,得出了叶片泵入口压力曲线。通过比较分析了绞刀系统是否安装蓄能器的压力图,确定最佳的蓄能器前单向阀开口大小。得出的压力曲线与现场所测曲线进行对比,可以为液压系统的仿真提供理论依据。

挖泥船疏浚横移过程线性二次型产量最优控制

在疏浚作业过程中,挖泥船主要的作业参数是由操作人员根据自己的经验、试挖情况以及挖泥船实际作业效果灵活确定的,而疏浚操作人员的经验和理论水平也相差较大,所以手动作业的实际产量要远远低于预计产量,且效率低下、作业成本偏高、作业质量较差。为了克服该缺点,提出了一种基于疏浚系统状态空间模型的线性二次型最优控制策略,并设计了最优控制跟踪器应用于绞吸挖泥船横移过程的控制中,该跟踪器是智能控制替代人工操作的一种有效方法。文章对应用二次型最优控制策略的效果进行了MATLAB仿真分析,仿真结果表明,采用了二次型最优控制策略后,系统稳定、响应快、滞后小,对期望输出的跟踪性好,可以应用于挖泥船疏浚作业过程中。

绞吸挖泥船吸扬系统数字仿真匹配计算

针对绞吸式挖泥船吸扬系统匹配选型不佳和产量预测不准等问题,利用数字仿真建模技术重构绞吸挖泥船吸扬系统的镜像数字模型。针对不同的绞吸挖泥船,通过调整模型参数可求解得到与之相对应的各子系统数字模型。在绞刀及其驱动系统中定量分析了绞刀转速、横移速度和吸口流速与泥浆比重的关系;在泥泵与管路系统中根据相似定律构建了泥泵-管路模型,研究了不同土质和泥浆浓度对泥泵扬程的影响,并求解预测出不同管道流速下的施工最佳工况点。将仿真系统应用到实验室小型疏浚平台上进行试验验证,试验结果显示数字系统能准确预测施工动态参数和产量,并能提前为施工策略提供指导性建议。

疏浚泥浆浓度最优控制跟踪器的设计与实现

在疏浚作业过程中,绞吸挖泥船主要的作业参数是由操作人员根据自己的经验确定的,而疏浚操作人员的经验和理论水平也相差较大,所以手动作业的实际产量要远远低于预计产量,效率低下,作业成本偏高,作业质量较差。为了克服该缺点,提出一种基于BP(Back-Propagation)神经网络的疏浚横移过程状态空间建模方法,并设计了疏浚横移过程线性二次型泥浆浓度最优控制跟踪器,应用于疏浚作业智能化控制中。仿真结果表明:二次型最优控制跟踪器的控制稳定性好、响应快、滞后小,跟踪效果好,泥浆浓度提高显著,较好地克服了人工操作缺点。

抓斗挖泥船提升系统动力学分析

根据抓斗挖泥船提升系统的实际工况,对挖泥船抓斗挖取的阻力进行了分析,并根据抓斗尺寸将其拟合成与颚瓣刃口插入物料内的垂直距离等相关的阻力函数。采用ADAMS轴套力方法将钢丝绳简化成若干段小圆柱体,并通过有限元模态分析将提升系统吊臂进行柔性化处理。采用ADAMS软件模型融合技术将上述子模型进行集成,构建抓斗挖泥船提升系统的虚拟样机。针对抓斗机工作循环、抓斗抓取等实际工况,对起升绳、闭合绳进行了动力学分析,并对吊臂进行刚柔混合动态特性分析。根据挖泥船提升系统的动力学仿真分析,可以清楚看出提升系统可能失效的时刻及位置,并预测不同工况下的危险因素。

耙吸挖泥船动力定位系统模型试验研究

为了评估耙吸挖泥船动力定位系统的定位能力,验证所设计的控制器、滤波器和推力分配算法的有效性,设计了耙吸挖泥船动力定位模型试验系统。文章介绍了耙吸挖泥船动力定位模型试验系统的结构、环境载荷模拟、控制系统和试验步骤,在不同的风、浪、流和作业工况下进行了模型试验。分析试验结果表明,所设计的模型试验控制系统具有较好的效果,为实船工程应用奠定了基础。