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基于等效截面法的TRD围护墙变形研究 认领
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作者 麻凤海 韩晓菲 《徐州工程学院学报:自然科学版》 CAS 2020年第2期6-10,共5页
为简化计算和分析围护墙的变形,以等厚度型钢混凝土搅拌墙为例,探索一种新的方法.该方法利用静力学中的力平衡原理,将TRD围护墙中的型钢以及混凝土这2种材料等效为1种规则截面的第3种材料.利用有限元软件建立不同墙厚、型钢间距及型钢... 为简化计算和分析围护墙的变形,以等厚度型钢混凝土搅拌墙为例,探索一种新的方法.该方法利用静力学中的力平衡原理,将TRD围护墙中的型钢以及混凝土这2种材料等效为1种规则截面的第3种材料.利用有限元软件建立不同墙厚、型钢间距及型钢规格下的4组模型,并对其进行对比分析后表明利用原始参数建立模型得到的结果与利用等效参数建立模型得到的结果相吻合.在进行TRD围护墙变形计算时,将该方法运用其中,可使计算更加简便. 展开更多
关键词 等效截面法 TRD工法 变形 围护结构 围护墙变形 有限元分析
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高铁与城铁混合底架结构的制造新工艺与工装设计研究 认领
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作者 王亚男 《现代制造工程》 CSCD 北大核心 2020年第2期94-98,共5页
研究了由高铁底架结构与城铁底架结构混合而成的轨道车辆车体底架的制造新工艺,该工艺方法有别于以往车辆在底架组成之前将牵引梁与枕梁进行预先合成的组焊方法,而是采用将枕梁单件、牵引梁单件和边梁拼焊成一个底架框架的方法进行组焊... 研究了由高铁底架结构与城铁底架结构混合而成的轨道车辆车体底架的制造新工艺,该工艺方法有别于以往车辆在底架组成之前将牵引梁与枕梁进行预先合成的组焊方法,而是采用将枕梁单件、牵引梁单件和边梁拼焊成一个底架框架的方法进行组焊。经试验确定,当工艺流程为分别预先组焊地板单件、牵引梁单件和枕梁单件,然后将边梁、牵引梁单件和枕梁单件拼焊成底架框架,最后将预先组焊的地板单件落入底架框架内,最终完成焊接时,得到的焊后变形量最小。变形趋势为宽度方向上两边梁向反面弯曲,长度方向上两端部向正面弯曲。通过设计专用的工装夹具,可使焊后变形量减小;通过焊前预制反变形,可使焊后变形量进一步减小。当焊前预制反变形量达到10 mm时,最大焊后变形量为3 mm。 展开更多
关键词 底架 工艺流程 变形 反变形
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考虑前缘桩锚支挡作用的滑坡变形预警指标研究 认领
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作者 姬超 陈好 +1 位作者 陈皓 龙伦刚 《水利水电技术》 北大核心 2020年第5期139-145,共7页
在考虑坡体前缘抗滑桩锚索对坡体下滑的阻挡作用的基础上,提出滑坡变形总量与变形速率预警指标。以四川岷江电化有限公司厂区西侧滑坡为例,利用强度折减法,通过FLAC数值模拟得到滑坡失稳破坏时的坡向位移,之后减去锚索所能承受的最大变... 在考虑坡体前缘抗滑桩锚索对坡体下滑的阻挡作用的基础上,提出滑坡变形总量与变形速率预警指标。以四川岷江电化有限公司厂区西侧滑坡为例,利用强度折减法,通过FLAC数值模拟得到滑坡失稳破坏时的坡向位移,之后减去锚索所能承受的最大变形量,拟定滑坡坡表变形总量预警阈值,并且根据前人统计研究得到的一般性滑坡变形速率与滑坡实际监测资料分析,拟定滑坡坡表变形速率预警阈值。计算结果表明:监测点JC01坡表变形总量蓝色、黄色、橙色与红色预警阈值分别为0.00 cm、38.84 cm、58.26 cm、77.68 cm;监测点JC02坡表变形总量蓝色、黄色、橙色与红色预警阈值分别为0.00 cm、63.00 cm、94.51 cm、126.01 cm;监测点JC03坡表变形总量蓝色、黄色、橙色与红色预警阈值分别为0.00 cm、46.84 cm、70.26 cm、93.68 cm;滑坡的坡表变形速率蓝色、黄色、橙色与红色预警阈值分别为0.00 mm/d、0.11 mm/d、1.61 mm/d、10.00 mm/d。研究结果为四川岷江电化有限公司厂区西侧滑坡预警阈值的拟定提供了相关参考与依据。 展开更多
关键词 滑坡 位移 变形速率 预警
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Ultra-fine-Grained Ferrite Prepared from Dynamic Reversal Austenite During Warm Deformation 认领
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作者 Hong-Bin Li Ming-Song Chen +2 位作者 Ya-Qiang Tian Lian-Sheng Chen Li-Qing Chen 《金属学报:英文版》 SCIE EI CAS CSCD 2020年第2期290-298,共9页
The ultra-fine-grained ferrite(UFGF) with the size of less than 1 μm is often difficult to be obtained for low-alloyed steel in practical production processing.In this study,considering the rod and wire production pr... The ultra-fine-grained ferrite(UFGF) with the size of less than 1 μm is often difficult to be obtained for low-alloyed steel in practical production processing.In this study,considering the rod and wire production process,a new method for preparing the UFGF with submicron scale is proposed by warm deformation of six passes with total strain of 2.6,followed by the cooling process in Gleeble-3500 thermo-mechanical simulator.The results show that the UFGF with an average size of 0.64 μm could be obtained via the phase transformation from austenite grains with an average size of 3.4 μm,which are achieved by the deformation-induced reversal austenization during the high strain rate warm deformation.The main driving force for the reversal transformation is the stress.And the interval between the passes also plays an important role in the reversal austenization. 展开更多
关键词 Ultra-fine-grained FERRITE DYNAMIC REVERSAL transformation(DRT) Warm DEFORMATION Deformation-induced REVERSAL TRANSFORMATION Cooling process
基于变形控制的薄壁板状压铸件加工精度保证 认领
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作者 黄志伟 李珊 《特种铸造及有色合金》 CAS 北大核心 2020年第3期294-296,共3页
以中间板为例,介绍了薄壁板状压铸件机加工时的主要难点,以及如何在开发时对加工方案进行分析,找出保证加工精度的控制要点,以提高过程开发的品质。在试生产时,通过数据分析,发现数控加工中心的热变形导致机加工孔位工程能力不足,通过... 以中间板为例,介绍了薄壁板状压铸件机加工时的主要难点,以及如何在开发时对加工方案进行分析,找出保证加工精度的控制要点,以提高过程开发的品质。在试生产时,通过数据分析,发现数控加工中心的热变形导致机加工孔位工程能力不足,通过采取误差补偿的方式解决了该问题,杜绝了位置度超差不良品的产生。 展开更多
关键词 薄壁板状零件 变形 机床热变形 误差补偿
Swelling characteristics of andesite foundation induced by water immersion and their influence on ballastless track subgrade 认领
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作者 DUAN Jun-yi YANG Guo-lin +2 位作者 HU Min LEI Xiao-qin LIN Yu-liang 《山地科学学报:英文版》 SCIE CSCD 2020年第4期1001-1012,共12页
To study the mechanical and deformation characteristics of ballastless track subgrade filled with micro-expansion fillers in a water-immersed environment, a physical model of ballastless track subgrade was constructed... To study the mechanical and deformation characteristics of ballastless track subgrade filled with micro-expansion fillers in a water-immersed environment, a physical model of ballastless track subgrade was constructed on a 1:2 scale with expansive andesite fillers. A water immersion test was carried out to model the soaking of the expansive soil foundation caused by rising groundwater. The swelling behaviors of the foundation and their influences upon the mechanics and deformations of the subgrade were analyzed. The lateral swelling pressure of the foundation and the heave of the subgrade obviously increased due to the water immersion, and the values were closely related to the overlying load and lateral restraint. The heave deformation of the double-line ballastless track subgrade showed significant nonuniformity along the lateral direction, causing the track slab to incline with a maximum inclination angle of 1.55×10^-3 deg. The heave of the foundation caused a heave in subgrade, but this transferred heave was significantly attenuated. The attenuation rate of the heave at the midline of the track slab was up to 13.38%. The attenuation characteristic can be fully utilized for the anti-heave deformation measures of railway subgrade in expansive soil areas. 展开更多
关键词 High-speed railway Expansive ANDESITE HEAVE DEFORMATION Lateral SWELLING pressure INCLINATION angle DEFORMATION attenuation
Ultraviolet 3D digital image correlation applied for deformation measurement in thermal testing with infrared quartz lamps 认领
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作者 Yali DONG Jiaqing ZHAO Bing PAN 《中国航空学报:英文版》 SCIE EI CAS CSCD 2020年第3期1085-1092,共8页
In thermal-structural testing of hypersonic materials and structures,deformation measurement on the front surface of an object directly heated by quartz lamps is highly necessary and very challenging.This work describ... In thermal-structural testing of hypersonic materials and structures,deformation measurement on the front surface of an object directly heated by quartz lamps is highly necessary and very challenging.This work describes a novel front-surface high-temperature deformation measurement technique,which adopts ultraviolet 3D digital image correlation(UV 3D-DIC)to observe and measure the high-temperature deformation fields on front surfaces directly heated by quartz lamps.Compared with existing blue light DIC techniques,the established UV 3D-DIC,which combines UV CCD camera,active UV illumination and bandpass filter imaging,can effectively suppress the strong disturbing light emitted by the quartz lamps and the heated sample itself during heating process.Two experiments were carried out to verify the robustness and accuracy of the developed technique:(1)direct observation of front surfaces of a hypersonic thermal structure sample heated from room temperature to 1050℃,and(2)front-surface thermal stain and coefficient of thermal expansion(CTE)measurement of an Inconel 718 sample up to 800℃.The well matched strain and CTE results with literature data show that UV 3D-DIC system is an effective technique for front-surface deformation measurement and has great potential in characterizing deformation response of hypersonic materials and structures subjected to transient aerodynamic heating. 展开更多
关键词 DEFORMATION DIC Front-surface Quartz lamp heating Ultraviolet 3D digital image correlation
Study on meso-mechanical behavior of sand based on its 2D geometrical model 认领
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作者 XU WenJie FENG ZeKang +1 位作者 YANG Han LIU GuangYu 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2020年第5期777-790,共14页
A comprehensive study on the meso-mechanical behaviors of sand with its 2D geometrical models was presented in this study.Based on the 2D geometrical models,database of sand particles,quantitative analysis on the geom... A comprehensive study on the meso-mechanical behaviors of sand with its 2D geometrical models was presented in this study.Based on the 2D geometrical models,database of sand particles,quantitative analysis on the geometrical characteristics of the studied sand particles was performed.A new clump generation algorithm based on fewer multiple overlapping circles was provided to accurately model the shape of sand particles,and was used to build the discrete element method(DEM)numerical model of the sand sample for DEM biaxial tests.The macro-and meso-mechanical behaviors of the studied sand samples were systematically analyzed.Deformation was mainly localized in a X-shaped shear zone,in which the particles experienced large displacements and rotations.Development of stress-induced anisotropy in particle and void orientations,as well as the mesoscopic fabric,was significant during the shearing process.Continuous collapse,generation,reduction,and extension of force chains occurred during the shearing process,especially after the peak stress was reached.This led to the fluctuations in the evolution of deviatoric stress and volumetric strain at macroscale,as well as the fabric anisotropy at mesoscale. 展开更多
关键词 SAND particle shape deformation localization fabric anisotropy discrete element method(DEM)
基于ANSYS的曲轴应力及变形敏感度分析 认领
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作者 施佳裕 王忠 +1 位作者 殷文元 夏骅 《机械设计与制造》 北大核心 2020年第6期231-234,240,共5页
建立了494柴油机曲轴有限元模型,采用试验的方法验证了模型的准确性.选择轴颈直径、过渡圆角半径、油孔直径等参数,模拟了最大爆发压力为15MPa时,曲轴过渡圆角应力和曲柄臂变形的变化规律,分析了曲轴结构参数与应力、变形敏感度系数的关... 建立了494柴油机曲轴有限元模型,采用试验的方法验证了模型的准确性.选择轴颈直径、过渡圆角半径、油孔直径等参数,模拟了最大爆发压力为15MPa时,曲轴过渡圆角应力和曲柄臂变形的变化规律,分析了曲轴结构参数与应力、变形敏感度系数的关系.结果表明,过渡圆角应力随轴颈直径、过渡圆角半径、重叠度的增加而减小,随油孔直径的增加而增加;曲柄臂变形随轴颈直径、曲柄销过渡圆角半径、重叠度的增加而减小,随主轴颈过渡圆角半径、油孔直径的增加而增加.曲柄销直径对过渡圆角应力最敏感,应力敏感度系数为-0.46;主轴颈直径对曲柄臂变形敏感度系数为-0.497,对变形最敏感. 展开更多
关键词 柴油机 曲轴 有限元模型 应力 变形 敏感度系数
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工业锅炉检验中遇到的问题及分析 认领
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作者 王永辉 《锅炉制造》 2020年第4期42-43,48,共3页
在工业锅炉的日常运行过程中,为了使运行安全得到充分的保障、运行效率得到有效的提高,需要定期检验锅炉的运行状况。基于此,论文首先阐述了工业锅炉的概念,之后分析了工业锅炉检验中经常遇到的四个问题:腐蚀问题、结垢问题、变形问题... 在工业锅炉的日常运行过程中,为了使运行安全得到充分的保障、运行效率得到有效的提高,需要定期检验锅炉的运行状况。基于此,论文首先阐述了工业锅炉的概念,之后分析了工业锅炉检验中经常遇到的四个问题:腐蚀问题、结垢问题、变形问题、裂纹问题,最后针对以上出现的问题给出了详细的解决方案,希望能够为以后相关方面的研究工作提供一些参考。 展开更多
关键词 工业锅炉检验 腐蚀 结垢 变形 裂纹
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Constitutive behavior and processing maps of a new wrought magnesium alloy ZE20 (Mg-2Zn-0.2Ce) 认领
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作者 Scott C.Sutton Alan A.Luo 《镁合金学报(英文)》 SCIE 2020年第1期111-126,共16页
ZE20(Mg-2Zn-0.2Ce)^2 is a new wrought magnesium alloy with improved extrudability and mechanical properties[1].To understand the constitutive behavior and workability of this new alloy,Gleeble thermomechanical testing... ZE20(Mg-2Zn-0.2Ce)^2 is a new wrought magnesium alloy with improved extrudability and mechanical properties[1].To understand the constitutive behavior and workability of this new alloy,Gleeble thermomechanical testing has been carried out in this study.The flow stress behavior of ZE20 was investigated between 250℃–450℃ and 10^–3 s^–1–1.0 s^–1 in isothermal compression.Constitutive descriptions of the flow stress are provided.A new general approach at application of the extended Ludwik equation is demonstrated and was found to be more accurate than the hyperbolic sine Arrhenius model while having a similar number of model constants.Processing maps were developed based on the experimental results and are verified with microstructural investigation.A region of safe processing with non-basal texture and high activity of dynamic recrystallization(DRX)was found between 375℃ and 450℃,from 10^–1 s^–1 to 10^–2.5 s^–1.A region of potentially safe processing with annealing that is associated with shear band nucleation of non-basal grains was identified for temperatures as low as 300℃ and rates as high as 10^–1 s^–1. 展开更多
关键词 Magnesium alloys Thermomechanical processing Constitutive behavior Processing map Deformation mechanisms
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LM-CDBN超高层变形预测模型的构建与应用 认领
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作者 邱冬炜 王彤 +2 位作者 段明旭 罗德安 王来阳 《西南交通大学学报》 EI CSCD 北大核心 2020年第2期310-316,共7页
为提高超高层建筑变形预测精度,对附有条件的深度信念网络(conditional deep belief network,CDBN)模型中权值及阈值调整方法进行了改进,使用LM (Levenberg-Marquardt)算法作为新的模型定权机制,构建了LMCDBN网络模型;将构建的LM-CDBN... 为提高超高层建筑变形预测精度,对附有条件的深度信念网络(conditional deep belief network,CDBN)模型中权值及阈值调整方法进行了改进,使用LM (Levenberg-Marquardt)算法作为新的模型定权机制,构建了LMCDBN网络模型;将构建的LM-CDBN超高层变形预测模型应用于一座298 m超高层建筑中;然后用训练误差、预测值拟合度、预测结果稳定性组成的综合评价体系对模型进行了评价;最后,将LM-CDBN模型分别与深度信念模型(deep belief network,DBN)、极限学习机(extreme learning machine,ELM)、基于无迹卡尔曼滤波的支持回归向量机(unscented Kalman filter-support vector regression,UKF-SVR)进行了预测结果对比.结果表明:在超高层建筑的变形预测中,相比DBN、ELM和UKF-SVR,LM-CDBN预测精度分别提升了32%、55%及24%,模型的信息提取稳定性及处理时变系统非线性问题的泛化能力得到了提高. 展开更多
关键词 深度信念网络 变形 预测 数据处理 参数估计
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扫描路径对薄壁件激光熔覆涂层形变的影响 认领
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作者 梁志刚 战金明 +3 位作者 师文庆 谢玉萍 黄江 安芬菊 《激光技术》 CAS CSCD 北大核心 2020年第4期447-450,共4页
为了改善收割机割刀等薄壁件在激光熔覆提升性能时容易产生形变的状况,采用Nd∶YAG激光加工系统在Hilbert分形式、轮廓偏置式和光栅式的3种不同的扫描路径下分别制备不同的铁基合金熔覆涂层,并取得了基材形变量和熔池深度等相关数据。... 为了改善收割机割刀等薄壁件在激光熔覆提升性能时容易产生形变的状况,采用Nd∶YAG激光加工系统在Hilbert分形式、轮廓偏置式和光栅式的3种不同的扫描路径下分别制备不同的铁基合金熔覆涂层,并取得了基材形变量和熔池深度等相关数据。结果表明,轮廓偏置式扫描路径在中心处的熔池深度最大,为0.75mm,且试样形变量达到了0.30mm;激光熔覆过程中熔池与其附近区域的温度梯度和基材形变量有着正相关的关系,熔池深度越大,温度越高,不同区域之间的温度梯度越大,产生的热应力越大,进而形变的倾向也会越大;光栅式扫描路径熔池深度随时间递增,温度梯度较小,故对基材的形变倾向较弱,且所制备的熔覆涂层质量较好,是适合于薄壁件激光熔覆的扫描路径。此研究对薄壁件激光熔覆具有指导意义。 展开更多
关键词 激光技术 激光熔覆 扫描路径 薄壁件 形变
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Progress and Prospect of Geophysical Research on Underground Gas Storage: A Case Study of Hutubi Gas Storage,Xinjiang,China 认领
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作者 ZHANG Bo SONG Lili +2 位作者 JI Zhanbo WANG Baoshan WU Zhide 《中国地震研究:英文版》 CSCD 2020年第2期187-209,共23页
Hutubi Underground Gas Storage(UGS) is an important part of China’s West-East Gas Pipeline Project. Its production safety also plays an essential role in ensuring peaking,emergency and reserve of natural gas in the r... Hutubi Underground Gas Storage(UGS) is an important part of China’s West-East Gas Pipeline Project. Its production safety also plays an essential role in ensuring peaking,emergency and reserve of natural gas in the region. Geophysical observations and research conducted on Hutubi UGS provide significant support for understanding the operation status and ensuring safe operation of the UGS. Since the beginning of the construction of Hutubi UGS and its production,several works including gas field observation experiments,rock experiments and numerical simulations have been conducted. Preliminary observational results show that during the initial operation stage of the UGS,the "breathing phenomenon"in caprock and microseismicity in the vicinity are closely related to the operation of the gas storage. However,rock experiments and numerical simulations show that these activities may gradually weaken with the multi-cycle operation of gas storage. The impact of the operation of Hutubi UGS in the surrounding areas is gradually weakening,and its operation tends to be stable. Implementing long-term and multi-method geophysical observations is able to provide us a better understanding of the relationship between the operation of UGS and regional geological hazards. On this basis,the corresponding geomechanical model can be established to form an effective risk management mechanism for gas storage operation. Thus,it is of great significance to understand its operation status,monitor storage conditions,guide production and operation,and ultimately guarantee the safe production of the gas storage. 展开更多
关键词 Hutubi Underground Gas Storage DEFORMATION SEISMICITY Rock experiment
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Deformation treatment and microstructure of graphene-reinforced metal matrix nanocomposites: A review of graphene post-dispersion 认领
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作者 Yong Mei Pu-zhen Shao +8 位作者 Ming Sun Guo-qin Chen Murid Hussain Feng-lei Huang Qiang Zhang Xiao-sa Gao Yin-yin Pei Su-juan Zhong Gao-hui Wu 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2020年第7期888-899,共12页
Graphene/aluminum(Gr/Al)composites have attracted the attention of researchers all over the world due to their excellent properties.However,graphene agglomerates easily because of the van der Waals force between graph... Graphene/aluminum(Gr/Al)composites have attracted the attention of researchers all over the world due to their excellent properties.However,graphene agglomerates easily because of the van der Waals force between graphite sheets,thereby affecting the performance of the composites.Decreasing the agglomeration of graphene and dispersing it uniformly in the Al matrix is a key challenge.In the preparation process,predispersion treatment and deformation treatment can play important roles in graphene dispersion.Researchers have conducted a series of research and literature reviews of the graphene predispersion and consolidation of composites.However,they paid less attention to post-deformation processing.This review summarizes different deformation treatments involved in the preparation process of Gr/Al composites and the evolution of the microstructure during the process.Research on deformation parameters is expected to further improve the properties of Gr/Al composites and would provide a deep understanding of the strengthening effect of graphene. 展开更多
关键词 graphene/aluminum composites deformation treatment DISPERSION MICROSTRUCTURE
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东峰煤矿3202回风顺槽支护技术探讨 认领
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作者 郭峰 《煤矿现代化》 2020年第5期169-172,共4页
针对东峰煤矿3202工作面回风顺槽变形较大,难以支护等问题,根据相邻工作面经验确定了工作面回风顺槽断面形状为矩形,断面尺寸为5.2m×3.5m;根据相似煤巷支护经验选用锚杆+锚索联合支护方式,并理论计算确定了各项支护参数;最后通过... 针对东峰煤矿3202工作面回风顺槽变形较大,难以支护等问题,根据相邻工作面经验确定了工作面回风顺槽断面形状为矩形,断面尺寸为5.2m×3.5m;根据相似煤巷支护经验选用锚杆+锚索联合支护方式,并理论计算确定了各项支护参数;最后通过现场工作面实际应用变形量监测,证明此支护方案可以保证3202回风顺槽的安全稳定。 展开更多
关键词 回风顺槽 变形量 支护
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一种隧道基坑多维度时变预测EPS模型的应用 认领
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作者 翁敦贤 《计算机测量与控制》 2020年第6期56-60,共5页
准确地掌握到正在施工的隧道深基坑所发生形变的态势,就可以进一步实现动态预测并采取有效的扼制举措,才能有效保障施工安全;据此提出一种基于信号分析法,通过耦合经验模态分解法、鸟群觅食算法(PSO)与单隐层前馈神经网络SLFNs学习算法... 准确地掌握到正在施工的隧道深基坑所发生形变的态势,就可以进一步实现动态预测并采取有效的扼制举措,才能有效保障施工安全;据此提出一种基于信号分析法,通过耦合经验模态分解法、鸟群觅食算法(PSO)与单隐层前馈神经网络SLFNs学习算法,结合成专为非线性情况下的基坑施工作多维时变预报模型EMD-PSO-SLFNs (EPS);其先将隧道形变的深坑序列分解时的EMD进行多尺度原生模态函数(IMF);并引入IMF、PSO-SLFNS变量序列进行预测,对其进行叠加预测,用模型的进行最终结果的运算预测,再用耦合PSO与SLFNs量化算法的作末端处理、变量序列进行预测;文章以南宁某隧道基坑施工为例,经过深层次透析得出,单凭EMD分解模型预测的相对误差为值在0.22%~0.42%之间,值δ=0.32%实际均差值;而进行EMD-PSO-SLFNs组合型作多维度时变分解模型预测的相对误差为0.31%~0.75%之间,值δ=0.64%,该预测精度明显高于前者,而且能在非平稳线性、变序情况下预测,为隧道基坑形变预测提供了一种实用新型的方法。 展开更多
关键词 隧道工程 基坑 形变 预测 模型
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轨道交通预制U型梁运输变形监测及受力分析 认领
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作者 陈刚 李世钧 +2 位作者 逯鹏 李建 林博云 《工业建筑》 CSCD 北大核心 2020年第6期123-127,134,共6页
U型梁能有效降低线路的高度、减少沟通噪声、养护方便。但对于U形截面等开口薄壁杆件,当荷载作用平面不是纵向对称面,即使是形心主惯性平面,梁除弯曲变形外,还将发生扭转变形,存在弯扭效应。其抗扭刚度和抗剪刚度较闭口薄壁构件或实心... U型梁能有效降低线路的高度、减少沟通噪声、养护方便。但对于U形截面等开口薄壁杆件,当荷载作用平面不是纵向对称面,即使是形心主惯性平面,梁除弯曲变形外,还将发生扭转变形,存在弯扭效应。其抗扭刚度和抗剪刚度较闭口薄壁构件或实心截面构件要小很多,且容易发生扭转失稳,导致突发的工程事故,因此有必要对其截面扭剪应力和应变问题进行深入研究。U型梁运输过程中因道路的不平顺会产生三点支承(一点托空)的情况,这些都会引起梁体混凝土的扭转变形。通过试验,研究U型梁在偏心荷载作用下的力学行为,分析U型梁扭剪应力对结构的影响,为类似桥梁设计提供试验和理论分析参考。 展开更多
关键词 预制U型梁 运输 变形 受力分析
Deformation behavior and microstructure evolution of titanium alloys with lamellar microstructure in hot working process: A review 认领
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作者 Pengfei Gao Mingwang Fu +2 位作者 Mei Zhan Zhenni Lei Yanxi Li 《材料科学技术:英文版》 SCIE EI CAS CSCD 2020年第4期56-73,共18页
Titanium alloys have been widely used in many industrial clusters such as automotive, aerospace and biomedical industries due to their excellent comprehensive properties. In order to obtain fine microstructures and fa... Titanium alloys have been widely used in many industrial clusters such as automotive, aerospace and biomedical industries due to their excellent comprehensive properties. In order to obtain fine microstructures and favorable properties, a well-designed multi-step thermomechanical processing(TMP) is critically needed in manufacturing of titanium components. In making of titanium components,subtransus processing is a critical step to breakdown lamellar microstructure to fine-structure in hot working process and thus plays a key role in tailoring the final microstructure and properties. To realize this goal, huge efforts have been made to investigate the mechanisms of microstructure evolution and flow behavior during the subtransus processing. This paper reviews the recent experimental and modelling progresses, which aim to provide some guidelines for the process design and microstructure tailoring for titanium alloy research community. The characteristics of the initial lamellar microstructure are presented, followed by the discussion on microstructure evolution during subtransus processing. The globularization of lamellar α is analyzed in detail from three aspects, i.e., globularization mechanism, heterogeneity and kinetics. The typical features of flow behaviors and the explanations of significant flow softening are then summarized. The recent advances in modelling of microstructure evolution and flow behaviors in the subtransus processing are also articulated. The current tantalized issues and challenges in understanding of the microstructure evolution and flow behaviors of the titanium alloys with lamellar microstructure are presented and specified in future exploration of them. 展开更多
关键词 TITANIUM alloys LAMELLAR MICROSTRUCTURE Deformation behavior MICROSTRUCTURE evolution
马兰矿28312工作面皮带巷支护技术的研究 认领
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作者 刘利斌 《机械管理开发》 2020年第4期37-39,共3页
针对马兰矿28312工作面所采煤层的具体地质赋存条件和巷道功能性,对马兰矿28312工作面皮带巷顶底板具体地质条件进行支护技术研究,选取巷道断面为矩形,尺寸为4.5 m×3.5 m;根据相似巷道支护经验选用锚杆+锚索联合支护方式,并理论计... 针对马兰矿28312工作面所采煤层的具体地质赋存条件和巷道功能性,对马兰矿28312工作面皮带巷顶底板具体地质条件进行支护技术研究,选取巷道断面为矩形,尺寸为4.5 m×3.5 m;根据相似巷道支护经验选用锚杆+锚索联合支护方式,并理论计算了各项支护参数.通过现场工作面实际应用变形量监测,证明此支护方案可以保证28312皮带巷的安全稳定. 展开更多
关键词 巷道 变形量 支护
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