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粉末烧结体热复压变形力的工程计算
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作者 洪慎章 曾振鹏 《上海交通大学学报》 EI CAS CSCD 北大核心 2000年第12期1631-1634,共4页
阐述用机械压力机进行粉末热锻时 Fe- 0 .2 2 C粉末烧结体热复压变形力的工程计算 .在相同温度下进行粉末烧结体热复压 ,锻造力的增加往往使锻造密度也增加 .介绍了粉末烧结体热复压试验用的设备、材料及方法 .通过热复压变形测定了一... 阐述用机械压力机进行粉末热锻时 Fe- 0 .2 2 C粉末烧结体热复压变形力的工程计算 .在相同温度下进行粉末烧结体热复压 ,锻造力的增加往往使锻造密度也增加 .介绍了粉末烧结体热复压试验用的设备、材料及方法 .通过热复压变形测定了一定锻造温度下的真实屈服应力 σs.根据Kuhn关于多孔预制坯的屈服准则和热复压时的应力应变关系提出复压力的理论公式 ,可导得简化的热复压变形力的工程计算公式 .本公式对粉末锻造实际生产有一定的实用意义 . 展开更多
关键词 粉末烧结体 热复压 变形力计算
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深井分层注水管柱受力变形计算方法改进 被引量:9
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作者 许志倩 闫相祯 杨秀娟 《油气田地面工程》 北大核心 2010年第3期22-24,共3页
针对原高压注水受力分析计算模型的不足之处,提出以下几点改进建议:区分计算完全与部分弯曲管柱的缩短量;细分工作状态,计算温度分布;在多级分层注水中考虑封隔器胶筒摩擦力和配水器水嘴压力与水量损失;增加下入、洗井和停注过程,完整... 针对原高压注水受力分析计算模型的不足之处,提出以下几点改进建议:区分计算完全与部分弯曲管柱的缩短量;细分工作状态,计算温度分布;在多级分层注水中考虑封隔器胶筒摩擦力和配水器水嘴压力与水量损失;增加下入、洗井和停注过程,完整描述整个注水过程中管柱受力变形变化情况。最后,编制深井分层注水管柱受力分析软件进行实例计算。 展开更多
关键词 高压注水 复合管柱 变形计算 封隔器 配水器
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考虑不同岩土抗力的加锚双排桩受力变形计算
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作者 李涛 吴丽杰 +2 位作者 续辰 杨玉坤 吴雨停 《西安理工大学学报》 北大核心 2023年第4期576-585,共10页
针对已有加锚双排桩计算模型对桩后滑裂面以下岩土层抗力处理的不足,考虑桩锚协同并将剪切滑裂角折减确定了滑裂面位置。然后将作用在前后排桩滑裂面以下的岩土抗力参数进行分段计算,最后采用分段坐标法推导建立了前后桩桩体挠度微分方... 针对已有加锚双排桩计算模型对桩后滑裂面以下岩土层抗力处理的不足,考虑桩锚协同并将剪切滑裂角折减确定了滑裂面位置。然后将作用在前后排桩滑裂面以下的岩土抗力参数进行分段计算,最后采用分段坐标法推导建立了前后桩桩体挠度微分方程,并与成都音乐厅基坑现场监测数据进行了对比。结果表明:该模型计算结果与实测结果较为吻合,特别是对后排桩的受力分析使后排桩桩身位移曲线更贴合实测结果;剪切滑裂面位置对桩体变形影响较大,当剪切滑裂角按1.29的折减系数计算时桩身位移更贴近实测数据。 展开更多
关键词 深基坑 双排桩 土抗 弹性地基梁 变形计算
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开式模锻型腔充满阶段和锻靠阶段的变形力 被引量:6
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作者 王华昌 《锻压技术》 CAS CSCD 北大核心 1994年第1期5-11,共7页
本文从开式模锻锻件成形过程中的金属流动特点来描述变形力分布的变化,推导出型腔充满阶段和锻靠阶段的变形力分布及二者之间的合理对应关系。
关键词 模锻 变形力计算 模具 设计
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Effective grouting area of jointed slope and stress deformation responses by numerical analysis with FLAC^(3D) 被引量:3
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作者 ZHU Zi-qiang LIU Qun-yi +1 位作者 ZENG Fan-he QING Du-gan 《Journal of Coal Science & Engineering(China)》 2009年第4期404-408,共5页
To study the grouting reinforcement mechanism in jointed rock slope, first, the theoretical deduction was done to calculate the critical length of slipping if the slope angle is larger than that of joint inclination; ... To study the grouting reinforcement mechanism in jointed rock slope, first, the theoretical deduction was done to calculate the critical length of slipping if the slope angle is larger than that of joint inclination; Second, the numerical calculation model was founded by FLAG^3D, so as to find the stress and deformation responses of rock mass in the state before and after grouting, the analysis results show that the range between the boundary of critical slipping block and the joint plane that passes the slope toe is the effective grouting area (EGA). After excavation, large deformation occurs along the joint plane. After grouting, the displacements of rock particles become uniform and continuous, and large deformations along the joint plane are controlled; the dynamic displacement can re- flect the deformation response of slope during excavation in the state before and after grouting, as well as the shear location of potential slip plane. After grouting, the dynamic displacement of each monitoring point reaches the peak value with very few time steps, which indicate that the parameters of the joint plane, such as strength and stiffness, are improved; the stress field becomes uniform. Tensile area reduces gradually; whole stability of the slope and its ability to resist tensile and shear stress are improved greatly. 展开更多
关键词 SLOPE STRESS DEFORMATION cranny FLAC^3D
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Computer simulation for the effect of coherent strain on the precipitation progress of binary alloy
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作者 卢艳丽 陈铮 王永欣 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2007年第5期634-640,共7页
Based on the microscopic elasticity theory and microscopic diffusion equation, the precipitation progress of the binary alloys including coherent strain energy was studied. The results show that coherent strain has ob... Based on the microscopic elasticity theory and microscopic diffusion equation, the precipitation progress of the binary alloys including coherent strain energy was studied. The results show that coherent strain has obvious effect on the coherent two-phase morphology and precipitation mechanism. With the increase of coherent strain energy, the particles shape changes from the randomly distributed equiaxed particels to elliptical precipitate shapes,their arrangement orientation increases; in the late stage of precipitation, the particle arrangement presents obvious directionality along the [10]and[01]directions, and the precipitation mechanism of alloy changes from typical spinodal decomposition mechanism to the mixture process which possesses the characteristics of both non-classical nucleation growth and spinodal decomposition mechanisms. 展开更多
关键词 binary alloy coherent strain precipitation progress computer simulation
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LASER SPECTRAL ANALYSIS OF STRAIN MEASUREMNT
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作者 姜耀东 陈至达 《Journal of China University of Mining and Technology》 1994年第1期100-111,共12页
Modern opticai theory has shown that the far field or Fraunbofer diffraction equipment is identical to the Fourier spectral analyzer. In the Fourier speetral analyzer the Fourier spectra or the Fraunhofer diffaction p... Modern opticai theory has shown that the far field or Fraunbofer diffraction equipment is identical to the Fourier spectral analyzer. In the Fourier speetral analyzer the Fourier spectra or the Fraunhofer diffaction pattern of a graph is formed on the back focal plane when a laser beam is directed on the graph lying on the front foeal plane ; the Fourier spectra of the graph is also subjected to change during the deformation of the graph. Through analyzing the change of Fourier spectra the deformation of the graph can be obtained. A few years ago,based on the above principles the authors proposed a new technique of strain measurement by laser spectral analysis. Demonstration and discussion will be made in detail in this paper. 展开更多
关键词 GRATINGS strain measurement Laser spectrum
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Deformation and stress distribution of the human foot after plantar ligaments release:A cadaveric study and finite element analysis 被引量:8
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作者 LIANG Jun YANG YunFeng +2 位作者 YU GuangRong NIU WenXin WANG YuBin 《Science China(Life Sciences)》 SCIE CAS 2011年第3期267-271,共5页
The majority of foot deformities are related to arch collapse or instability,especially the longitudinal arch.Although the relationship between the plantar fascia and arch height has been previously investigated,the s... The majority of foot deformities are related to arch collapse or instability,especially the longitudinal arch.Although the relationship between the plantar fascia and arch height has been previously investigated,the stress distribution remains unclear.The aim of this study was to explore the role of the plantar ligaments in foot arch biomechanics.We constructed a geometrical detailed three-dimensional (3-D) finite element (FE) model of the human foot and ankle from computer tomography images.The model comprised the majority of joints in the foot as well as bone segments,major ligaments,and plantar soft tissue.Release of the plantar fascia and other ligaments was simulated to evaluate the corresponding biomechanical effects on load distribution of the bony and ligamentous structures.These intrinsic ligaments of the foot arch were sectioned to simulate different pathologic situations of injury to the plantar ligaments,and to explore bone segment displacement and stress distribution.The validity of the 3-D FE model was verified by comparing results with experimentally measured data via the displacement and von Mise stress of each bone segment.Plantar fascia release decreased arch height,but did not cause total collapse of the foot arch.The longitudinal foot arch was lost when all the four major plantar ligaments were sectioned simultaneously.Plantar fascia release was compromised by increased strain applied to the plantar ligaments and intensified stress in the midfoot and metatarsal bones.Load redistribution among the centralized metatarsal bones and focal stress relief at the calcaneal insertion were predicted.The 3-D FE model indicated that plantar fascia release may provide relief of focal stress and associated heel pain.However,these operative procedures may pose a risk to arch stability and clinically may produce dorsolateral midfoot pain.The initial strategy for treating plantar fasciitis should be non-operative. 展开更多
关键词 BIOMECHANICS finite element analysis foot arch LIGAMENT STRESS
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Modelling and analysis for a pilot relief valve using CFD method and deformation theory of thin plates 被引量:4
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作者 YUAN XianJu GUO KongHui 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第6期979-998,共20页
The current work is concerned with modelling and analysis for a pilot relief valve, thus successfully bringing a systematic method for designing and analyzing similar valves. The essence of the work is to solve two im... The current work is concerned with modelling and analysis for a pilot relief valve, thus successfully bringing a systematic method for designing and analyzing similar valves. The essence of the work is to solve two important problems, one for positions of the pilot valve influenced by flow force and the other is for the opening of the relief valve governed by a thin annular plate. The computational fluid dynamics(CFD) method is used to present the flow force. Using a series of experiments, the flow rate versus pressure drop shows the rationality of the CFD results. In order to obtain the opening of relief valve with higher accuracy, the large deflection theory of thin plates is adopted. An equivalent method for replacing the concentrated force is innovatively proposed so that all of the loads of the plates can be given by a unified expression, which reduces the number of the governing equations and intermediate boundary conditions. For presenting a very simple and reliable method for solving the governing equation, an unconstrained nonlinear optimization is innovatively introduced to solve the deflection of the thin annular plate. Being verified by finite-element method(FEM) of the relief valve, the equivalent method and optimization can solve deflection of thin plates rapidly and accurately. Reflected through a complete model for the pilot relief valve, the theoretical flow rate of the pilot relief valve is consistent with experimental conclusion. Once again, the comparisons bring us insight into the accuracy of the method adopted in the current work. 展开更多
关键词 pilot valve relief valve MODELLING large deflection unconstrained nonlinear optimization
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