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Preparation of ultra-fine grain Ni-Al-WC coating with interlocking bonding on austenitic stainless steel by laser clad and friction stir processing 被引量:4
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作者 熊拥军 邱子力 +3 位作者 李瑞迪 袁铁锤 吴宏 刘锦辉 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第11期3685-3693,共9页
The ultra-fine structured Ni?Al?WC layer with interlocking bonding was fabricated on austenitic stainless steel by combination of laser clad and friction stir processing (FSP). Laser was initially applied to Ni?Al ele... The ultra-fine structured Ni?Al?WC layer with interlocking bonding was fabricated on austenitic stainless steel by combination of laser clad and friction stir processing (FSP). Laser was initially applied to Ni?Al elemental powder preplaced on the austenitic stainless steel substrate to produce a coating for further processing. The as-received coating was subjected to FSP treatment, processed by a rotary tool rod made of WC?Co alloy, to obtain sample for inspection. Microstructure, phase constitutions, hardness and wear property were investigated by methods of scanning electronic microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) microanalysis, and X-ray diffraction (XRD), hardness test alongside with dry sliding wear test. The results show that the severe deformation effect exerted on the specimen resulted in an ultra-fine grain layer of about 100μmin thickness and grain size of 1?2μm. Synergy between introduction of WC particles to the deformation layer and deformation strengthening contributes greatly to the increase in hardness and friction resistance. An interlocking bonding between the coating and matrix which significantly improves bonding strength was formed due to the severe deformation effect. 展开更多
关键词 laser clad friction stir processing Ni-Al-WC coating ultra-fine grain interlocking bonding
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Preparation of Well Dispersed and Ultra-Fine Ce(Zr)O_2 Mixed Oxide by Mechanochemical Processing 被引量:2
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作者 程昌明 李永绣 +1 位作者 周雪珍 陈伟凡 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第6期775-779,共5页
Ultra-fine CeO_2-ZrO_2 mixed oxide was successfully synthesized by wet-solid phase mechanochemical processing, Ce_2(CO_3)_3·8H_2O, ZrOCl_2·xH_2O and ammonia were used as reactants. It is found that the cryst... Ultra-fine CeO_2-ZrO_2 mixed oxide was successfully synthesized by wet-solid phase mechanochemical processing, Ce_2(CO_3)_3·8H_2O, ZrOCl_2·xH_2O and ammonia were used as reactants. It is found that the crystalline Ce_2(CO_3)_3·8H_2O and ZrOCl_2·xH_2O are changed to amorphous cerium and zirconium hydroxide precursor after milling with ammonia, and Ce_(0.15)Zr_(0.85)O_2 mixed oxide with pure tetragonal phase structure and medium particle size(D_(50))less than 1μm is formed by calcining precursor over 673 K. The XRD patterns indicate that the crystal unite size increases with rising calcining temperature due to crystal growth. However, the particle size and BET surface area of the Ce(Zr)O_2 mixed oxide decreases with rising calcining temperature, which may be attributed to the contract of particles and the vanish of holes inside grains. 展开更多
关键词 ceria-zirconia mixed oxide ultra-fine powders mechanochemical process rare earths
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Challenges and opportunities in the production of magnesium parts by directed energy deposition processes
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作者 Gürel Cam Ali Günen 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第5期1663-1686,共24页
Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aero... Mg-alloys have gained considerable attention in recent years for their outstanding properties such as lightweight,high specific strength,and corrosion resistance,making them attractive for applications in medical,aerospace,automotive,and other transport industries.However,their widespread application is hindered by their low formability at room temperature due to limited slip systems.Cast Mg-alloys have low mechanical properties due to the presence of casting defects such as porosity and anisotropy in addition to the high scrap.While casting methods benefit from established process optimization techniques for these problems,additive manufacturing methods are increasingly replacing casting methods in Mg alloys as they provide more precise control over the microstructure and allow specific grain orientations,potentially enabling easier optimization of anisotropy properties in certain applications.Although metal additive manufacturing(MAM)technology also results in some manufacturing defects such as inhomogeneous microstructural evolution and porosity and additively manufactured Mg alloy parts exhibit lower properties than the wrought parts,they in general exhibit superior properties than the cast counterparts.Thus,MAM is a promising technique to produce Mg alloy parts.Directed energy deposition processes,particularly wire arc directed energy deposition(WA-DED),have emerged as an advantageous additive manufacturing(AM)technique for metallic materials including magnesium alloys,offering advantages such as high deposition rates,improved material efficiency,and reduced production costs compared to subtractive processes.However,the inherent challenges associated with magnesium,such as its high reactivity and susceptibility to oxidation,pose unique hurdles in the application of this technology.This review paper delves into the progress made in the application of DED technology to Mg-alloys,its challenges,and prospects.Furthermore,the predominant imperfections,notably inhomogeneous microstructure evolution and porosity,observed in Mg-alloy components manufactured through DED are discussed.Additionally,the preventive measures implemented to counteract the formation of these defects are explored. 展开更多
关键词 Additive manufacturing DED processes Arc-DED wire arc additive manufacturing(WAAM) 3-D printing High deposition rate
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DATA PROCESSING ON LINEARIZATION OF HOT-WIRE ANEMOMETER
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作者 Li Sufen(Department of Power Engineering ,NUAA 29 Yudao Street,Nanjing 210016,P.R.China) 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1994年第2期224-228,共5页
A method of data processing to determine the coefficients of linearization equations for 1050 anemometer (produced by Thermo-Systems Inc. -TSI, USA) with the sensors made of domestic hot wire using the program preferr... A method of data processing to determine the coefficients of linearization equations for 1050 anemometer (produced by Thermo-Systems Inc. -TSI, USA) with the sensors made of domestic hot wire using the program preferred in this Paper is described. By calculation and test, it is indicated that the error resulting from this method is about 0. 5% of the full scale and less than TSl's. By using this method we can set up the calibration curve according to the measurement range and the diameter of the hot wire at a certain accuracy. 展开更多
关键词 measurements data processing LINEARIZATION aero dynamic test HOT-wire ANEMOMETERS
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Microstructure and texture evolution in titanium subjected to friction roll surface processing and subsequent annealing 被引量:1
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作者 施梅勤 高山善匡 +2 位作者 马淳安 渡部英男 井上博史 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第11期2616-2627,共12页
Commercial purity and high purity titanium sheets were initially strained by a new technique, named as friction roll surface processing (FRSP). Severe strain was imposed into the surface layer and strain gradient wa... Commercial purity and high purity titanium sheets were initially strained by a new technique, named as friction roll surface processing (FRSP). Severe strain was imposed into the surface layer and strain gradient was formed through the thickness of the sheet. The microstructure and texture in as-strained state were investigated by optical microscopy and X-ray diffraction technique On the surface of the sheets, ultra-fine grains were found to have a sharp texture with a preferred orientation strongly related to the FRSP direction. The evolution of microstructure and crystallographic texture of FRSPed samples during recrystallization were also studied by electron back-scattered diffraction (EBSD) technique after being annealed at selected temperatures and time. The results indicated that the preferred orientations resulting from FRSP and annealing in the surface layer were formed during rolling and its recrystallization textures were reduced by FRSP. In addition, the texture evolved stably without change in main components during the annealing. 展开更多
关键词 TITANIUM friction roll surface processing severe plastic deformation preferred orientation RECRYSTALLIZATION textureevolution ultra-fine grains
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Image Processing System for Air Classification Using Linear Discriminant Analysis 被引量:1
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作者 Atsunori Tayaoka Eriko Tayaoka +1 位作者 Tsuyoshi Hirajima Keiko Sasaki 《Computational Water, Energy, and Environmental Engineering》 2017年第2期192-204,共13页
An air classifier is used in the recycling process of covered electric wire in the recycling factories, in which the covered electric wires are crushed, sieved, and classified by the air classifier, which generates wa... An air classifier is used in the recycling process of covered electric wire in the recycling factories, in which the covered electric wires are crushed, sieved, and classified by the air classifier, which generates wastes. In these factories, operators manually adjust the air flow rate while checking the wastes discharged from the separator outlet. However, the adjustments are basically done by trial and error, and it is difficult to do them appropriately. In this study, we tried to develop the image processing system that calculates the ratio of copper (Cu) product and polyvinyl chloride (PVC) in the wastes as a substitute for the operator’s eyes. Six colors of PVC (white, gray, green, blue, black, and red) were used in the present work. An image consists of foreground and background. An image’s regions of interest are objects (Cu particles) in its foreground. However, the particles having a color similar to the background color are buried in the background. Using the difference of two color backgrounds, we separated particles and background without dependent of background. The Otsu’ thresholding was employed to choose the threshold to maximize the degree of separation of the particles and background. The ratio of Cu to PVC pixels from mixed image was calculated by linear discriminant analysis. The error of PVC pixels resulted in zero, whereas the error of Cu pixels arose to 4.19%. Comparing the numbers of Cu and PVC pixels within the contour, the minority of the object were corrected to the majority of the object. The error of Cu pixels discriminated as PVC incorrectly became zero percent through this correction. 展开更多
关键词 COVERED ELECTRIC wire Air Classification RECYCLING IMAGE processing Linear DISCRIMINANT Analysis
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Processing limit maps for the stable deformation of dieless drawing
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作者 Yong He Xue-feng Liu +1 位作者 Jian-xin Xie Hong-gang Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2011年第3期330-337,共8页
Tin bronze wires were produced by dieless drawing. The effects of heating power, the distance between cooler and heater as well as feeding speed on the diameter, the temperature field, and the deformation region profi... Tin bronze wires were produced by dieless drawing. The effects of heating power, the distance between cooler and heater as well as feeding speed on the diameter, the temperature field, and the deformation region profile of the wires were investigated. The results indi-cated that each processing parameter exhibited both lower and upper limits of stable deformation based on the criterion of stable deformation with the diameter fluctuation of ±0.05 mm. Both the temperature and its gradient of the deformation region increased with increasing heating power under stable deformation, but decreased with an increase in feeding speed. As the distance between cooler and heater increased, the temperature of the deformation region increased and the slope of the deformation region profile decreased. The processing limit map of sta-ble deformation exhibited a closed curve and the unstable deformation consisted of wire breakage and diameter fluctuations. 展开更多
关键词 tin bronze wire dieless drawing processing parameters turning method
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Neural network modeling for dynamic pulsed GTAW process with wire filler based on MATLAB
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作者 赵冬斌 陈善本 +1 位作者 吴林 陈强 《China Welding》 EI CAS 2001年第2期10-15,共6页
Double-sided weld pool shapes were determined by multiple welding parameters and wire feed parameters during pulsed GTAW with wire filler. Aiming at such a system with multiple inputs and outputs, an effective modelin... Double-sided weld pool shapes were determined by multiple welding parameters and wire feed parameters during pulsed GTAW with wire filler. Aiming at such a system with multiple inputs and outputs, an effective modeling method, consisting of the impulse signal design, model structure and parameter identification and verification, was developed based on MATLAB software. Then, dynamic neural network models, TDNNM (Topside dynamic neural network model) and BHDNNM (Backside width and topside height dynamic neural network model), were established to predict double-sided shape parameters of the weld pool. The characteristic relationship of the welding process was simulated and analyzed with the models. 展开更多
关键词 GTAW with wire filler dynamic process modeling neural network MATLAB
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Synthesis and Characterization of Ultra-fine Cr_2O_3 from Hydrogen Reduction of K_2CrO_4
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作者 BAI Yulan XU Hongbin +1 位作者 ZHANG Yi LI Zuohu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2008年第2期181-183,共3页
As a part of the green process for manufacturing chromium compounds, two steps are involved in the synthesis of ultra-fine Cr2O3 powders: the first is the hydrogen reduction of K2CrO4 into intermediate trivalent (C... As a part of the green process for manufacturing chromium compounds, two steps are involved in the synthesis of ultra-fine Cr2O3 powders: the first is the hydrogen reduction of K2CrO4 into intermediate trivalent (Cr^3+) or tetravalent (Cr^4+) chromium compounds; the second is the decomposing of the intermediate into Cr2O3 by heat treating. The intermediate is well characterized by means of SEM, XRD, and XPS. The possible reaction mechanism of the process is analyzed. 展开更多
关键词 hydrogen reduction ultra-fine chromic oxide potassium chromate green process
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Effects of Fillerwire Composition along with Different Pre- and Post-Heat Treatment on Mechanical Properties of AISI 4130 Welded by the GTAW Process
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作者 Ali Emamian Ardalan Emamian Amir Hossein Kowkabi 《Materials Sciences and Applications》 2010年第3期135-140,共6页
This research intends to find out the optimal mechanical properties of AISI 4130 steel welded by the GTAW process. Six test plates were joined by two types of filler wire with similar chemical composition to the base ... This research intends to find out the optimal mechanical properties of AISI 4130 steel welded by the GTAW process. Six test plates were joined by two types of filler wire with similar chemical composition to the base metal, and with lower carbon content and slightly higher alloy elements content compared to the first one. Test plates then exerted three different pre-heat and post-heat treatments on both groups. The three types of heat treatments were alternatively without pre-heat and post-heat, with pre-heat only, and finally with pre-heat and post-heat. Tensile, side bends and impact tests (for weld zone and HAZ) have been conducted. Results show that using low-carbon filler wire along with pre- and post-heat resulted in outstanding mechanical properties. 展开更多
关键词 HAZ (Heat Affected Zone) Filler wire Pre- and Post-heat Treatments GTAW process
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Gradient Ultra-fine Grained Surface Layer in 6063 Aluminum Alloy Obtained by Means of Rotational Accelerated Shot Peening
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作者 Ying LIU Hailu XU +2 位作者 He XIAN Yanfang LIU Zheng LI 《Research and Application of Materials Science》 2021年第1期38-46,共9页
Gradient ultra-fine grained surface layer in 6063 aluminum alloy was obtained by means of a novel surface self-nanocrystallization technique,namely rotational accelerated shot peening(RASP)treatment.The average grain ... Gradient ultra-fine grained surface layer in 6063 aluminum alloy was obtained by means of a novel surface self-nanocrystallization technique,namely rotational accelerated shot peening(RASP)treatment.The average grain sizes along the vertical section vary from hundreds of nanometers in the top surface to micrometers in the matrix.By using orthogonal experimental design to compare roughness values and hardness values,we synthesized the processing parameters to obtain sample of smaller roughness values and higher hardness. 展开更多
关键词 rotational accelerated shot peening gradient ultra-fine grained structure orthogonal experimental design processing parameters
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高压线束支架多工位连续模设计
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作者 王富春 蒙以嫦 +1 位作者 关来德 苏治德 《科技创新与应用》 2024年第20期127-129,133,共4页
该文分析高压线束支架的冲压成形工艺及排样方法,阐述该连续冲裁模的结构及工作零件的加工方法,凹模采用镶拼结构,节约模具钢,零件加工难度降低,制造成本降低。实践证明,该模具结构合理,冲件质量稳定,较好地满足冲件精度和批量生产的要求。
关键词 冲压工艺 排样 连续模 直通式 高压线束支架
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基于SYSWELD的大厚板窄间隙双丝埋弧焊热过程数值模拟
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作者 周方明 单磊 +3 位作者 杨志东 赵利忠 孙亚杰 朱莎莎 《江苏科技大学学报(自然科学版)》 CAS 2024年第5期45-50,共6页
基于60 mm厚Q345R钢,开展了窄间隙双丝埋弧焊焊接试验,得到了合理的工艺参数,焊缝成型平整均匀无任何缺陷.通过SYSWELD有限元软件对大厚板窄间隙双丝埋弧焊焊接热过程进行数值模拟分析,模拟的熔池宽与高和实际相比,误差率均控制在5%以内... 基于60 mm厚Q345R钢,开展了窄间隙双丝埋弧焊焊接试验,得到了合理的工艺参数,焊缝成型平整均匀无任何缺陷.通过SYSWELD有限元软件对大厚板窄间隙双丝埋弧焊焊接热过程进行数值模拟分析,模拟的熔池宽与高和实际相比,误差率均控制在5%以内,并利用热电偶装置测得热影响区热循环曲线与模拟的热循环曲线变化趋势基本一致,具有升温快,降温慢的特点,验证了该模型的有效性.为后续利用该模型,进一步探究不同参数或边界条件对于大厚板窄间隙双丝埋弧焊焊接热过程与应力-应变规律提供理论指导. 展开更多
关键词 大厚板 窄间隙双丝埋弧焊 热过程 数值模拟 SYSWELD
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机械振动对电弧增材制造2319铝合金微观组织与机械性能的影响
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作者 张亮 卞文卓 +1 位作者 卢佳豪 刘江平 《河北科技大学学报》 CAS 北大核心 2024年第2期189-197,共9页
为了解决电弧增材制造试样晶粒粗大、机械性能较差等问题,在电弧增材制造2319铝合金过程中施加机械振动,分析了机械振动频率和幅度对试样微观组织和机械性能的影响。结果显示:机械振动使熔池流动性提高,熔池更加铺展,层宽增加,层高降低... 为了解决电弧增材制造试样晶粒粗大、机械性能较差等问题,在电弧增材制造2319铝合金过程中施加机械振动,分析了机械振动频率和幅度对试样微观组织和机械性能的影响。结果显示:机械振动使熔池流动性提高,熔池更加铺展,层宽增加,层高降低;振动破碎了生长过程中的枝晶,使INZ晶粒尺寸减小14.49μm,ITZ晶粒尺寸减小4.68μm;枝晶间隙处的溶质元素含量降低,晶界析出相变得断续且细小,PLC效应间隔增加,材料延伸率显著提高;机械振动频率和机械振动幅度改变时纵向和横向延伸率分别提升了38.2%,15.7%和29.3%,52.5%,而强度变化并不显著。采用机械振动辅助电弧增材制造能够在不影响强度的前提下显著提高试样的塑性,可为机械振动在增材制造领域的广泛应用提供技术参考。 展开更多
关键词 焊接工艺与设备 电弧增材制造 机械振动 微观组织 机械性能
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飞机线束装配螺栓螺距数量图像测量方法研究
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作者 闫静 陆珊珊 张忆鑫 《航空计算技术》 2024年第2期32-36,共5页
飞机线束是电气线路互联系统(EWIS)的装配单元,重要的飞机线束常以线束捆的方式用P型金属带垫卡箍固定在飞机上。卡箍固定线束的装配质量检测要求之一是卡箍螺栓与螺母拧紧后,螺栓应露出螺母螺距数量大于规定值。为实现飞机线束装配检... 飞机线束是电气线路互联系统(EWIS)的装配单元,重要的飞机线束常以线束捆的方式用P型金属带垫卡箍固定在飞机上。卡箍固定线束的装配质量检测要求之一是卡箍螺栓与螺母拧紧后,螺栓应露出螺母螺距数量大于规定值。为实现飞机线束装配检测智能化,提出一种基于图像自动识别P型卡箍螺栓伸出螺母螺距数量的方法。分析确立螺栓伸出螺母单侧牙顶中点为需要识别的图像特征点,并建立利用牙顶特征点计算螺距数量的公式;通过对图像进行预处理、边缘检测、轮廓提取及拟合、极值点检测等得到牙顶特征点个数;针对不同具体图像实例进行了实验验证。 展开更多
关键词 飞机线束 卡箍装配质量 螺纹螺距 数字化检测 图像处理
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高强铝合金电弧增材制造的研究进展 被引量:1
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作者 王树文 陈树君 +5 位作者 赵骐跃 袁涛 蒋晓青 赵鹏经 山河 丁梧桐 《材料工程》 EI CAS CSCD 北大核心 2024年第7期1-14,共14页
高强铝合金因具有高强度、低密度、优异的延展性和抗腐蚀性,成为了航空航天和汽车应用零件最常用的金属材料之一。电弧增材制造技术具有快速原位成形制造复杂结构零部件的能力,非常适用于中型或大型高强铝合金铝部件的制造。本文综合分... 高强铝合金因具有高强度、低密度、优异的延展性和抗腐蚀性,成为了航空航天和汽车应用零件最常用的金属材料之一。电弧增材制造技术具有快速原位成形制造复杂结构零部件的能力,非常适用于中型或大型高强铝合金铝部件的制造。本文综合分析了高强铝合金电弧增材制造工艺和设备研发现状、高强铝合金电弧增材的固有属性和缺陷以及主要的性能优化手段,讨论了组织和性能的固有特征和复合增材制造技术对组织和性能的影响。针对电弧增材制造高强铝合金不可忽略的本质冶金缺陷、特征性能需求和多种优化工艺的优劣等问题,提出了电弧增材制造高强铝合金综合评价体系、成分设计和丝材开发、专用热处理制度和复合增材制造技术的协同性等发展方向,以期为电弧增材制造高强铝合金的性能提升和应用推广提供重要参考。 展开更多
关键词 电弧增材制造 高强铝合金 冶金缺陷 优化工艺 复合增材制造
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一种改进的Live-Wire交互式图像分割算法 被引量:11
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作者 高新波 雷云 姬红兵 《系统工程与电子技术》 EI CSCD 北大核心 2003年第8期915-917,958,共4页
提出了一种改进的Live Wire交互式图像分割算法。与原Live Wire算法相比 ,改进算法在不增加算法复杂度的同时 ,大大提高了图像分割的性能 ,而且在 3个方面弥补了原算法的不足 :(1)对噪声相当敏感 ;(2 )不能有效地区分图像中的强弱边缘 ;... 提出了一种改进的Live Wire交互式图像分割算法。与原Live Wire算法相比 ,改进算法在不增加算法复杂度的同时 ,大大提高了图像分割的性能 ,而且在 3个方面弥补了原算法的不足 :(1)对噪声相当敏感 ;(2 )不能有效地区分图像中的强弱边缘 ;(3)不适用于边缘弯曲程度较大的图像。将改进算法与窗宽 /窗位调整算法相结合用于医学图像分割中 。 展开更多
关键词 交互式图像分割 Live-wire算法 CANNY算子 窗宽/窗位调整
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无润滑条件下工艺参数对Al6063金刚石线切表面粗糙度影响
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作者 高永华 吕涵 +3 位作者 杜倡 武胜 李士鹏 秦旭达 《制造技术与机床》 北大核心 2024年第8期138-142,共5页
金刚石线锯因具有超高的硬度和耐磨性,常用于切削各种硬质材料,因加工过程摩擦较为剧烈,通常加冷却润滑介质,但一些特殊需求下,铝合金需要线切时无法施加冷却液。基于单因素试验法,在无润滑条件下进行了Al6063材料的线锯试验,分析了加... 金刚石线锯因具有超高的硬度和耐磨性,常用于切削各种硬质材料,因加工过程摩擦较为剧烈,通常加冷却润滑介质,但一些特殊需求下,铝合金需要线切时无法施加冷却液。基于单因素试验法,在无润滑条件下进行了Al6063材料的线锯试验,分析了加工表面不同区域粗糙度的分布规律以及配重、线速度与进给速度对加工表面粗糙度的影响规律。结果表明,加工面中间位置表面粗糙度最大;在试验范围内配重越大,对应的表面粗糙度值越小;金刚石线锯线速度越大,其表面粗糙度值越小;进给速度越小,所对应的表面粗糙度值越小。试验结果对提高加工表面质量有实际参考价值。 展开更多
关键词 金刚石线锯 工艺参数 表面粗糙度 白光干涉仪
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基于力学仿真分析的PCCP断丝预警及报警阈值评估方法
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作者 马宝龙 朱新民 崔炜 《中国农村水利水电》 北大核心 2024年第5期1-8,共8页
分析了钢丝的预应力作用机理和管道的破坏过程,提出了一种基于力学仿真分析的PCCP断丝预警与报警阈值评估方法。通过ABAQUS程序建立了PCCP有限元模型,模拟了包括铺设垫层、安装管道、分步回填在内的完整施工过程,计算了不同埋深、不同... 分析了钢丝的预应力作用机理和管道的破坏过程,提出了一种基于力学仿真分析的PCCP断丝预警与报警阈值评估方法。通过ABAQUS程序建立了PCCP有限元模型,模拟了包括铺设垫层、安装管道、分步回填在内的完整施工过程,计算了不同埋深、不同设计工作压力近百种工况下管道预应力钢丝、钢筒和管芯混凝土的应力状态,提出将管芯混凝土在水锤作用下起裂的最大允许断丝数作为爆管预警阈值,将管道埋地承载力极限状态的最大允许断丝数作为爆管报警阈值,并分析了不同工作内压和埋深条件下PCCP断丝预警与报警阈值之间的关系。 展开更多
关键词 埋深 断丝预警和报警 PCCP 管土相互作用 回填过程
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双脉冲自保护药芯焊丝电弧焊工艺稳定性
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作者 张恒铭 金秀鹃 +4 位作者 苟宁年 蒋小霞 石玗 周海 刘伟 《焊接学报》 EI CAS CSCD 北大核心 2024年第5期90-97,共8页
鉴于自保护药芯焊丝在野外焊接的重要性,尤其对于野外大型机械等关键零部件的应急修复,提高其焊接成形精度至关重要,因此研究了自保护药芯焊丝在双脉冲电弧模式下的工艺稳定性.为了实现电弧焊工艺稳定性的有效控制,采用单因素试验研究... 鉴于自保护药芯焊丝在野外焊接的重要性,尤其对于野外大型机械等关键零部件的应急修复,提高其焊接成形精度至关重要,因此研究了自保护药芯焊丝在双脉冲电弧模式下的工艺稳定性.为了实现电弧焊工艺稳定性的有效控制,采用单因素试验研究了双脉冲参数对焊接过程稳定性的影响,发现熔滴平均尺寸与电流变异系数关系密切,因此,选取强弱脉冲频率、占空比、强弱脉冲峰值和基值7个双脉冲参数作为输入值,建立一种基于RBF-BP神经网络的熔滴平均尺寸预测模型,结果表明,该预测模型有效、可行,为控制熔滴过渡过程稳定性提供了技术支撑. 展开更多
关键词 自保护药芯焊丝 工艺稳定性 熔滴过渡 RBF-BP神经网络
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