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3D analytical solution for a rotating transversely isotropic annular plate of functionally graded materials 被引量:2
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作者 CHEN Jiang-ying CHEN Wei-qiu 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第7期1038-1043,共6页
The analytical solution for an annular plate rotating at a constant angular velocity is derived by means of direct displacement method from the elasticity equations for axisymmetric problems of functionally graded tra... The analytical solution for an annular plate rotating at a constant angular velocity is derived by means of direct displacement method from the elasticity equations for axisymmetric problems of functionally graded transversely isotropic media. The displacement components are assumed as a linear combination of certain explicit functions of the radial coordinate, with seven undetermined coefficients being functions of the axial coordinate z. Seven equations governing these z-dependent functions are derived and solved by a progressive integrating scheme. The present solution can be degenerated into the solution of a rotating isotropic functionally graded annular plate. The solution also can be degenerated into that for transversely isotropic or isotropic homogeneous materials. Finally, a special case is considered and the effect of the material gradient index on the elastic field is illustrated numerically. 展开更多
关键词 Functionally graded materials Transversely isotropic Rotating annular plate Analytical solution
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The Phototropism of Jurassic Petrified Wood in North China Plate 被引量:2
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作者 JIANG Zikun LIU Benper +6 位作者 HUANG Min DENG Shenghui LU Yuanzheng LIU Lu LI Mingming DONG Shuxin WANG Yongdong 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第5期1352-1355,共4页
Trees on the side directly exposed to sunlight generally grow faster than on the opposite side, a phenomenon termed plant phototropism. There are in situ vertical trunks of silicified wood in the Xiadelongwan area of ... Trees on the side directly exposed to sunlight generally grow faster than on the opposite side, a phenomenon termed plant phototropism. There are in situ vertical trunks of silicified wood in the Xiadelongwan area of Yanqing County, north Beijing, where the first National Geologic Park of Petrified Wood of China has been built since 2002. A few trunks have well-preserved growth rings. One petrified stump from the formation shows a positive phototropism direction of SW230°. As compared with the modern normal growth stumps in Beijing plain area, which have a positive phototropism direction of SW210 °± 5°, the evidence of wood phototropism supports the conclusion of previous palaeomagnetic studies that the North China Plate has rotated clockwise since the Late Jurassic. The known petrified wood stumps in the Yanshan-Liaoning area are mainly found from the strata of 165-136 Ma, which corresponds to the main stage of the Yanshanian Movement. 展开更多
关键词 Jurassic petrified wood PHOTOTROPISM North China plate rotation PALAEOGEOGRAPHY
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Magneto-elastic dynamics and bifurcation of rotating annular plate 被引量:4
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作者 胡宇达 朴江民 李文强 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第9期269-279,共11页
In this paper, magneto-elastic dynamic behavior, bifurcation, and chaos of a rotating annular thin plate with various boundary conditions are investigated. Based on the thin plate theory and the Maxwell equations, the... In this paper, magneto-elastic dynamic behavior, bifurcation, and chaos of a rotating annular thin plate with various boundary conditions are investigated. Based on the thin plate theory and the Maxwell equations, the magneto-elastic dynamic equations of rotating annular plate are derived by means of Hamilton's principle. Bessel function as a mode shape function and the Galerkin method are used to achieve the transverse vibration differential equation of the rotating annular plate with different boundary conditions. By numerical analysis, the bifurcation diagrams with magnetic induction, amplitude and frequency of transverse excitation force as the control parameters are respectively plotted under different boundary conditions such as clamped supported sides, simply supported sides, and clamped-one-side combined with simply-anotherside. Poincare′ maps, time history charts, power spectrum charts, and phase diagrams are obtained under certain conditions,and the influence of the bifurcation parameters on the bifurcation and chaos of the system is discussed. The results show that the motion of the system is a complicated and repeated process from multi-periodic motion to quasi-period motion to chaotic motion, which is accompanied by intermittent chaos, when the bifurcation parameters change. If the amplitude of transverse excitation force is bigger or magnetic induction intensity is smaller or boundary constraints level is lower, the system can be more prone to chaos. 展开更多
关键词 magneto-elastic rotating annular plate Bessel function bifurcation and chaos
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Geochemistry and Geochronology of Circumferential Dykes of the Franklin LIP: A Rotated Perspective on Plate Reconstruction
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作者 Steven DENYSZYN Grant COX Galen HALVERSON 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第S1期30-,共1页
In addition to an extrusive volcanic component and associated sills,the Neoproterozoic Franklin Large Igneous Province(LIP)comprises a giant radiating dyke swarm spanning an arc of ca.110?,as well as a less-
关键词 Geochemistry and Geochronology of Circumferential Dykes of the Franklin LIP A Rotated Perspective on plate Reconstruction
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窄条控制件对旋转振荡板尾流的控制
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作者 魏婷婷 邵传平 《中国计量学院学报》 2014年第4期391-397,共7页
两个小窄条对称地放于两侧,对宽厚比B/H=3的旋转振荡平板的尾流旋涡脱落进行抑制.板在平行于来流位置附近绕对称轴作旋转振荡,振幅为10°.窄条长边与板的旋转轴平行,窄条表面与来流方向垂直,窄条宽度与板的厚度之比b/H=1/3.控制参... 两个小窄条对称地放于两侧,对宽厚比B/H=3的旋转振荡平板的尾流旋涡脱落进行抑制.板在平行于来流位置附近绕对称轴作旋转振荡,振幅为10°.窄条长边与板的旋转轴平行,窄条表面与来流方向垂直,窄条宽度与板的厚度之比b/H=1/3.控制参数为窄条位置.尾流流动显示图片和尾流脉动速度谱结果表明,当窄条位于有效区域内时,板两侧的涡脱落得到有效抑制.有效区尺度随着无量纲频率的增大而增大,随着雷诺数的增大而减小. 展开更多
关键词 旋转振荡平板 旋涡脱落 流动控制 控制件
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刚性基底弹性转动约束矩形板各受载条件下屈曲分析
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作者 吴韬 莫时旭 +2 位作者 向勇斌 邹泽群 郑艳 《上海交通大学学报》 EI CAS CSCD 北大核心 2022年第1期114-126,共13页
为探究对于刚性基底上边界不同弹性转动约束刚度矩形板的单侧屈曲行为,研究了在刚性基底上弹性转动约束矩形薄板四边受线性压力和均布剪力屈曲的问题.采用Rayleigh-Ritz法,依据不同受载情况的屈曲形变提出合适的挠曲面函数,由板屈曲时... 为探究对于刚性基底上边界不同弹性转动约束刚度矩形板的单侧屈曲行为,研究了在刚性基底上弹性转动约束矩形薄板四边受线性压力和均布剪力屈曲的问题.采用Rayleigh-Ritz法,依据不同受载情况的屈曲形变提出合适的挠曲面函数,由板屈曲时能量的变分推得临界屈曲荷载理论解.运用相关性稳定验算公式,获得薄板在弯-剪复合应力下的屈曲公式.建立相关有限元模型,分析不同基底刚度和弯剪比对弯-剪复合屈曲应力的影响,并与一个半充填式钢箱-混凝土组合梁负弯矩区腹板屈曲试验结果比较.结果表明:半充填混凝土作刚性基底时可简化为刚度系数略低于5的弹性基底. 展开更多
关键词 矩形薄板 RITZ法 刚性基底 弹性转动约束 临界屈曲系数 弯-剪复合应力
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弹性支承上弹性转动约束矩形薄板线性荷载压屈分析
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作者 吴韬 莫时旭 郑艳 《河南理工大学学报(自然科学版)》 CAS 北大核心 2022年第3期172-180,共9页
为探讨边界约束下不同刚度对受线性压力作用矩形板稳定性的影响,研究了弹性支承上弹性转动约束的矩形薄板线性压屈问题。采用基于能量变分原理的Ritz能量法,根据屈曲形变提出合适的挠曲面函数,由其能量变分推得临界屈曲荷载理论解。通... 为探讨边界约束下不同刚度对受线性压力作用矩形板稳定性的影响,研究了弹性支承上弹性转动约束的矩形薄板线性压屈问题。采用基于能量变分原理的Ritz能量法,根据屈曲形变提出合适的挠曲面函数,由其能量变分推得临界屈曲荷载理论解。通过有限元分析得到此类矩形板压屈荷载数值解,结果表明:荷载梯度较小时误差不超过2.8%;荷载梯度较大时,通过回归得到修正系数,误差不超过4.7%。同时建立临界纵横比、荷载梯度与板的边界转动约束刚度和支承刚度之间的关系式,根据计算结果分析,边界转动约束刚度为0.8~100时对薄板受压稳定性影响显著。 展开更多
关键词 矩形薄板 Ritz能量法 有限元分析 弹性转动约束 线性压屈 临界屈曲荷载
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Rotating Squeezed Vacua as Time Machines
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作者 S. Al Saleh L. A. Al Asfar A. Mahroussah 《Journal of Modern Physics》 2016年第3期304-311,共8页
Squeezed quantum vacua seems to violate the averaged null energy conditions (ANEC’s), because they have a negative energy density. When treated as a perfect fluid, rapidly rotating Casimir plates will create vorticit... Squeezed quantum vacua seems to violate the averaged null energy conditions (ANEC’s), because they have a negative energy density. When treated as a perfect fluid, rapidly rotating Casimir plates will create vorticity in the vacuum bounded by them. The geometry resulting from an arbitrarily extended Casimir plates along their axis of rotation is similar to van Stockum spacetime. We observe closed timelike curves (CTC’s) forming in the exterior of the system resulting from frame dragging. The exterior geometry of this system is similar to Kerr geometry, but because of violation of ANEC, the Cauchy horizon lies outside the system unlike Kerr blackholes, giving more emphasis on whether spacetime is multiply connected at the microscopic level. 展开更多
关键词 Squeezed quantum vacua seems to violate the averaged null energy conditions (ANEC’s) because they have a negative energy density. When treated as a perfect fluid rapidly rotating Casimir plates will create vorticity in the vacuum bounded by them. The geometry resulting from an arbitrarily extended Casimir plates along their axis of rotation is similar to van Stockum spacetime. We observe closed timelike curves (CTC’s) forming in the exterior of the system resulting from frame dragging. The exterior geometry of this system is similar to Kerr geometry but because of violation of ANEC the Cauchy horizon lies outside the system unlike Kerr blackholes giving more emphasis on whether spacetime is multiply connected at the microscopic level.
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Frequency Veering of Rotating Metal Porous Twisted Plate with Cantilever Boundary Using Shell Theory
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作者 Y.Y.Liu Y.X.Hao +3 位作者 W.Zhang L.T.Liu S.W.Yang Y.T.Cao 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2022年第2期282-302,共21页
The frequency veering of a metal porous rotating cantilever twisted plate with twist angle and stagger angle is investigated.Metal porous materials may have the characteristics of gradient or uniform distribution alon... The frequency veering of a metal porous rotating cantilever twisted plate with twist angle and stagger angle is investigated.Metal porous materials may have the characteristics of gradient or uniform distribution along the thickness direction.Based on the classical shell theory,considering the influence of centrifugal force produced by high-speed rotation,the free vibration equations of a rotating cantilever twisted plate are derived.Through the polynomial function and Rayleigh-Ritz method,the natural frequencies and mode shapes of the metal porous cantilever twisted plate in both static and rotating states are derived.The accuracy of the present theory and calculation results is confirmed by a comparison between them and the results available from the literature and those obtained from Abaqus.The influences of the thickness ratio,porosity,twist angle,stagger angle and rotational velocity on the frequency veering and mode shape shift of the rotating cantilever twisted plate with porous material under three different distributions are analyzed.It should be mentioned that the frequency veering accompanied by mode shape shift occurs in both static and dynamic states. 展开更多
关键词 Frequency veering Rotating twisted plate Cantilever boundary Metal porous
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Discussion on the relationship between the Yanshanian Movement and cratonic destruction in North China 被引量:20
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作者 Yu WANG Lixin SUN +1 位作者 Liyun ZHOU Yueting XIE 《Science China Earth Sciences》 SCIE EI CAS CSCD 2018年第5期499-514,共16页
The relationship between the Yanshanian Movement, destruction of the North China Craton(NCC), and subduction of the western Pacific plate is crucial to reconstructing the middle-late Mesozoic tectonic evolution of the... The relationship between the Yanshanian Movement, destruction of the North China Craton(NCC), and subduction of the western Pacific plate is crucial to reconstructing the middle-late Mesozoic tectonic evolution of the eastern Asian continent and margin. The Yanshanian Movement was a globally important change in crustal tectonics during the Middle-Late Jurassic.Previous research has systematically studied the formation and evolution of the Yanshanian Movement, focusing on the timing and location of tectonic movements, and the sedimentary and volcanic strata. However, the question of whether the tectonic activity occurred globally, and the characteristics of the Yanshanian Movement remain debated. The main argument is that if a tectonic movement can only be characterized by a regional or local disconformity, and if the tectonic movement occurred in an intracontinental setting, with extensive deformation but with no disconformity despite volcanic eruptions and magmatic intrusions, accompanied by changes in crustal structure and composition, should it be defined as a tectonic event or process? This question requires further analysis. The main aim of this study is to distinguish whether the Yanshanian Movement is a local feature of the eastern Asian continent, or a global tectonic event related to subduction of the Pacific Plate. In this paper, based on previous research, we discuss the spatial and temporal evolution of the Yanshanian Movement, the controlling tectonic mechanisms, and its relationship to the reactivation and destruction of the NCC and the subduction of the western Paleo-Pacific slab.We emphasize that the Yanshanian Movement in the Middle-Late Jurassic is distinct from the lithospheric thinning responsible for Early Cretaceous extension and magmatism related to the destruction of the NCC. The various tectonic stages were constrained by different dynamics and tectonic settings, or by different tectonic events and processes. Therefore, it is possible that the deformation and reactivation of the NCC contributed to its destruction, in addition to lithospheric thinning. Finally, we discuss whether the Yanshanian Movement was associated with the destruction of the NCC. 展开更多
关键词 Yanshanian Movement North China Craton destruction Paleo-Pacific plate subduction Intracontinental deformation Layered crustal rotation
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