检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

航道碎冰条件下极地船舶冰压力分布特性

中国舰船研究 2024年第2期19卷 53-61页

作者：黄家煜周利刘仁伟丁仕风江苏科技大学船舶与海洋工程学院江苏镇江212100 上海交通大学船舶海洋与建筑工程学院上海200240

[目的]为研究船舶与碎冰作用过程中船体冰压力的分布情况,对航道碎冰条件下的极地船舶进行数值模拟分析。[方法]采用离散元法(DEM)对船舶与碎冰进行建模,假设碎冰是由理想的二维圆盘构成,并考虑海流对碎冰单元的浮力、拖曳力及附加质量... 详细信息

[目的]为研究船舶与碎冰作用过程中船体冰压力的分布情况,对航道碎冰条件下的极地船舶进行数值模拟分析。[方法]采用离散元法(DEM)对船舶与碎冰进行建模,假设碎冰是由理想的二维圆盘构成,并考虑海流对碎冰单元的浮力、拖曳力及附加质量的影响;利用MT Uikku号冰水池模型试验结果对数值模型进行验证,对比分析不同航速和冰况对船体区域冰压力的影响。[结果]结果显示,当船舶在航道碎冰中运动时,冰载荷主要集中在船首;船首区域的冰压力随冰厚、航速和碎冰密集度的增加而增大,其中冰厚是影响冰压力幅值最大的因素;碎冰区航行船舶的首部区域冰压力影响最大,船首过渡区冰压力影响显著。[结论]所提数值分析方法可为极地船舶安全航行和结构设计提供一定的参考。

关键词：极地船舶冰载荷碎冰冰压力离散元法

基于GISSMO损伤模型的高强度钢碰撞失效行为研究

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

船舶工程 2024年第7期46卷 111-121页

作者：张健谭嘉伟姬贺港刘仁伟江苏科技大学船舶与海洋工程学院

为了研究不同失效模型对碰撞仿真结果的影响，以期准确描述材料的失效行为。以船用高强度钢EH36为研究对象，设计2个温度下不同应力状态的材料拉伸试验，得到其不同温度下的力学性能、载荷和位移数据，将试验结果与拉伸仿真联合，反求... 详细信息

为了研究不同失效模型对碰撞仿真结果的影响，以期准确描述材料的失效行为。以船用高强度钢EH36为研究对象，设计2个温度下不同应力状态的材料拉伸试验，得到其不同温度下的力学性能、载荷和位移数据，将试验结果与拉伸仿真联合，反求出广义增量应力状态依赖损伤模型（GISSMO）的参数；构建冰体与船体板架的碰撞仿真，对比不考虑失效，考虑V-M失效准则以及GISSMO损伤模型的仿真结果。结果表明，考虑GISSMO损伤模型相比于V-M失效准则，碰撞力峰值和板架吸能情况都有所减小。由于GISSMO损伤模型考虑了不同应力三轴度对材料失效的影响，所获得的损伤形态更接近于真实情况，因此GISSMO损伤模型能较好预测EH36钢材的变形及失效行为。

关键词： GISSMO损伤模型高强度钢碰撞失效行为

在线全文

学校读者我要写书评

暂无评论

基于航行状态的多元避碰周界研究

江苏科技大学学报（自然科学版） 2024年第2期38卷 1-7页

作者：刘浩丁仕风周利刘仁伟江苏科技大学船舶与海洋工程学院镇江212100

为实现船舶智能航行,建立基于船舶航行状态的多元避碰周界.通过识别船舶航行风险,分析避碰双方的主尺度、航速、航向等多元因素对航行安全的影响机制,提出危险周界和预警周界的解析表达方法,构建面向海上安全航行的多元避碰周界.通过实... 详细信息

为实现船舶智能航行,建立基于船舶航行状态的多元避碰周界.通过识别船舶航行风险,分析避碰双方的主尺度、航速、航向等多元因素对航行安全的影响机制,提出危险周界和预警周界的解析表达方法,构建面向海上安全航行的多元避碰周界.通过实例分别模拟了多航行状态的船舶和复杂海上障碍物的数字化安全界限,初步验证了多元避碰周界的可行性,可作为船舶避碰决策、船舶智能航行的理论参考.

关键词：航行安全船舶避碰模型船舶运动状态

在线全文

学校读者我要写书评

暂无评论

基于解调重构的跳频信号辐射源个体识别方法

电讯技术 2024年第2期64卷 252-260页

作者：刘人玮查雄李天昀章昕亮龚佩信息工程大学信息系统工程学院郑州450001

现有跳频信号辐射源个体识别方法大多围绕跳变瞬态的特征进行讨论,其捕获和精准定位的难度较大。因此,提出了一种基于解调重构的跳频信号辐射源个体识别方法,能够有效利用跳频信号的稳态信息进行辐射源个体识别。首先对跳频信号进行跳... 详细信息

现有跳频信号辐射源个体识别方法大多围绕跳变瞬态的特征进行讨论,其捕获和精准定位的难度较大。因此,提出了一种基于解调重构的跳频信号辐射源个体识别方法,能够有效利用跳频信号的稳态信息进行辐射源个体识别。首先对跳频信号进行跳变定时,提取出各跳的基带波形;然后解调出各跳的符号,并将其经过理想成型滤波器,得到理想的重构基带波形;最后将原始波形和重构波形一起送入神经网络,得到分类结果。给出发射机畸变模型和畸变参数范围,经过多次测试给出网络参数的建议取值范围,并进行验证实验。实验结果表明,该方法能够有效地完成跳频信号辐射源个体识别任务。

关键词：跳频信号特定辐射源识别解调重构

Numerical Simulations of the Ice Load of a Ship Navigating in Level Ice Using Peridynamics

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2019年第11期121卷 523-550页

作者： Yanzhuo Xue renwei liu Yang liu Lingdong Zeng Duanfeng Han College of Shipbuilding Engineering Harbin Engineering UniversityHarbin150001China

In this study,a numerical method was developed based on peridynamics to determine the ice loads for a ship navigating in level *** analysis of threedimensional ice specimen with tensile and compression loading are carried out *** effects of ice thickness,sailing speed,and ice properties on the mean ice loads were also *** is observed that the ice fragments resulting from the icebreaking process will interact with one another as well as with the water and ship *** ice fragments may rotate,collide,or slide along the ship hull,and these ice fragments will eventually drift away from the *** key characteristics of the icebreaking process can be obtained using the peridynamic model such as the dynamic generation of cracks in the ice sheet,propagation and accumulation of ice fragments,as well as collision,rotation,and sliding of the ice fragments along the ship *** simulation results obtained for the ice loads and icebreaking process were validated against those determined from the Lindqvist empirical formula and there is good agreement between the results.

关键词： Peridynamics ice load level ice ship-ice interaction ice properties convergence

Joints of continuous carbon fiber reinforced lithium aluminosilicate glass ceramics matrix composites to Ti60 alloy brazed using Ti-Zr-Ni-Cu active alloy

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2019年第3期32卷 715-722页

作者： Shengpeng HU Dongdong FENG Long XIA Ke WANG renwei liu Zhentao XIA Hongwei NIU Xiaoguo SONG School of Materials Science and Engineering Harbin Institute of Technology Shanghai Institute of Spacecraft Equipment

Continuous carbon fiber reinforced lithium aluminosilicate glass ceramics matrix composites(C_f/LAS composites) are joined to Ti60 alloy vacuum brazed using Ti-Zr-Ni-Cu brazing alloy. The effects of the brazing temperature on the interfacial microstructure and mechanical properties of brazed joints are investigated in details. The interfacial microstructure varies apparently with an increase of the brazing temperature. The thicknesses of the banded Ti solid solution(Ti(s, s)) and the reactive layer between Cf/LAS composites and the interlayer grow gradually. The mechanical properties of brazed joints increase firstly and then decrease with an increasing temperature. In addition, a joint that is brazed at 980 °C for 10 min shows the highest shear strength of$38.13 MPa. At the same time, the fracture paths of brazed joints also change as the temperature increases. When the brazing temperature is 950 °C, the fracture position is in the TiC + ZrC +Ti_2O + ZrSi_2+ Ti_5Si_3 layer on the composite side. When the brazing temperature is 980 °C, the fracture position is on the side of the braze seam(Ti, Zr)2(Ni, Cu), Ti_2O + ZrSi_2+ Ti_5Si_3 layer,and carbon fiber in the composite material. When the brazing temperature is 990 °C, the fracture position is in the Ti_2O + ZrSi_2+ Ti_5Si_3 layer on the composite side and the carbon fiber in the composite material.

关键词： Brazing Composites Mechanical properties Microstructure Titanium alloys

AN EFFICIENT METHOD FOR STRUCTURAL OPTIMIZATION

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 1986年第4期2卷 348-361页

作者： Xia renwei liu Peng (Beijing Institute of Aeronautics and Astronautics) Beijing Institute of Aeronautics and Astronautics Beijing China

Based on the dual theory of nonlinear mathematical programming and the secnnd orderTaylor series expansions of functions,an efficient algorithm for structural optimum design has *** main advantages of this method are the generality in use,the efficiency in computa-tion and the capability in identifying automatically the set of active *** the basis of thevirtual work principle,formulas in terms of element stresses for the first and second order derivativesof nodal displacement and stress with respect to design variables are *** applying the Saint-Venant’s principle,the computational efforts involved in the Hessian matrix associated with theiterative expression can be significantly *** method is especially suitable for optimumdesign of large scale *** typical examples have heen optimized to test its uasefulness.

关键词： structural optimization design sensitivity analysis mathematical programming

Experimental study on mercury content in flue gas of coal-fired units based on laser-induced breakdown spectroscopy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Plasma Science and Technology 2020年第7期22卷 75-82页

作者： Kai RONG Zhenzhen WANG Ruomu HU renwei liu Yoshihiro DEGUCH Junjie YAN Jiping liu State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049People’s Republic of China Graduate School of Technology Industrial and Social SciencesTokushima UniversityTokushima 770-8501Japan Moe Key Laboratory of Thermo-Fluid Science and Engineering Xi'an Jiaotong UniversityXi'an 710049People’s Republic of China

Accurate measurement of trace heavy metal mercury(Hg) in flue gas of coal-fired units is great significance for ecological and environmental *** gas was used to simulate the actual flue gas of a power plant in this study.A laser-induced breakdown spectroscopy(LIBS)system for Hg measurement in mixed gas was built to study the effect of mixed gas pressure,Hg concentration in mixed gas and delay time on Hg *** experimental results show that the appropriate low mixed gas pressure can obtain high Hg signal intensity and signal to noise *** Hg signal intensity and signal to noise ratio increased with the increase of Hg concentration in mixed *** Hg signal intensity and signal to noise ratio decreased with the increase in delay *** to the above results,the optimized measurement conditions can be *** Hg concentrations in mixed gas were quantitatively analyzed by the internal standard method and traditional calibration method *** relative error of prediction of the test sample obtained by the internal standard method was within 11.11%.The relative error of prediction of the traditional calibration method was less than 14.54%.This proved that the internal standard method can improve the accuracy of quantitative analysis of Hg concentration in flue gas using LIBS.

关键词： laser-induced breakdown spectroscopy flue gas trace heavy metal quantitative analysis

Quantifying the Effects of Near-Surface Viscosity on Seismic Acquisition Geometry: A case study from Chepaizi Exploration Area, Junggar Basin (NW China)

在线全文

学校读者我要写书评

暂无评论

APPLIED GEOPHYSICS 2024年第3期21卷 433-439页

作者： Ren, Hongqin liu, Tao Zhang, Xu Zhang, Jian Ding, renwei Sinopec Geophys Co Ltd Shengli Branch Dongying 257086 Shandong Peoples R China Shandong Univ Sci & Technol Coll Earth Sci & Engn Qingdao 266590 Shandong Peoples R China

The Chepaizi Exploration Area, Junggar Basin (NW China) holds substantial importance for seismic exploration endeavors, yet it poses notable challenges due to the intricate nature of its subsurface and near-surface conditions. To address these challenges, we introduce a novel and comprehensive workflow tailored to evaluate and optimize seismic acquisition geometries while considering the impacts of near-surface viscosity. By integrating geological knowledge, historical seismic data, and subsurface modeling, we conduct simulations employing the visco-acoustic wave equation and reverse-time migration to produce detailed subsurface images. The quality of these images is quantitatively evaluated using a local similarity metric, a pivotal tool for evaluating the accuracy of seismic imaging. The culmination of this workflow results in an automated optimization strategy for acquisition geometries that enhances subsurface exploration. Our proposed methodology underscores the importance of incorporating near-surface viscosity effects in seismic imaging, offering a robust framework for improving the accuracy of subsurface imaging. Herein, we aim to contribute to the advancement of seismic imaging methodologies by providing valuable insights for achieving high-quality seismic exploration outcomes in regions characterized by complex subsurface and near-surface conditions.

关键词： seismic acquisition visco-acoustic reverse-time migration local similarity WAVE-PROPAGATION