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Nonlinear free vibration of piezoelectric cylindrical nanoshells 预览
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作者 Yanqing WANG Yunfei LIU J. W. ZU 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第5期601-620,共20页
The nonlinear vibration characteristics of the piezoelectric circular cylindri- cal nanoshells resting on an elastic foundation are analyzed. The small scale effect and thermo-electro-mechanical loading are taken into... The nonlinear vibration characteristics of the piezoelectric circular cylindri- cal nanoshells resting on an elastic foundation are analyzed. The small scale effect and thermo-electro-mechanical loading are taken into account. Based on the nonlocal elastic- ity theory and Donnell’s nonlinear shell theory, the nonlinear governing equations and the corresponding boundary conditions are derived by employing Hamilton’s principle. Then, the Galerkin method is used to transform the governing equations into a set of ordinary differential equations, and subsequently, the multiple-scale method is used to obtain an approximate analytical solution. Finally, an extensive parametric study is conducted to examine the effects of the nonlocal parameter, the external electric potential, the temperature rise, and the Winkler-Pasternak foundation parameters on the nonlinear vibration characteristics of circular cylindrical piezoelectric nanoshells. 展开更多
关键词 PIEZOELECTRIC CYLINDRICAL NANOSHELL NONLINEAR vibration Donnell's NONLINEAR shell THEORY nonlocal elasticity THEORY multiple-scale method size effect
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Postbuckling analysis of functionally graded graphene platelet-reinforced polymer composite cylindrical shells using an analytical solution approach 预览
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作者 S. BLOORIYAN R. ANSARI +2 位作者 A. DARVIZEH R. GHOLAMI H. ROUHI 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第7期1001-1016,共16页
An analytical approach is proposed to study the postbuckling of circular cylindrical shells subject to axial compression and lateral pressure made of functionally graded graphene platelet-reinforced polymer composite ... An analytical approach is proposed to study the postbuckling of circular cylindrical shells subject to axial compression and lateral pressure made of functionally graded graphene platelet-reinforced polymer composite (FG-GPL-RPC). The governing equations are obtained in the context of the classical Donnell shell theory by the von K′arm′an nonlinear relations. Then, based on the Ritz energy method, an analytical solution approach is used to trace the nonlinear postbuckling path of the shell. The effects of several parameters such as the weight fraction of the graphene platelet (GPL), the geometrical properties, and distribution patterns of the GPL on the postbuckling characteristics of the FG-GPL-RPC shell are analyzed. 展开更多
关键词 cylindrical shell nanocomposite GRAPHENE PLATELET (GPL) POSTBUCKLING ANALYTICAL solution
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Multiscale Radiative Transfer in Cylindrical Coordinates 预览
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作者 Wenjun Sun Song Jiang Kun Xu 《应用数学与计算数学学报(英文)》 2019年第1期117-139,共23页
The radiative transfer equations in cylindrical coordinates are important in the application of inertial confinement fusion.In comparison with the equations in Cartesian coordinates,an additional angular derivative te... The radiative transfer equations in cylindrical coordinates are important in the application of inertial confinement fusion.In comparison with the equations in Cartesian coordinates,an additional angular derivative term appears in the cylindrical case.This term adds great difficulty for a numerical scheme to keep the conservation of total energy.In this paper,based on weighting factors,the angular derivative term is properly discretized,and the interface fluxes in the radial r-direction depend on such a discretization as well.A unified gas kinetic scheme(UGKS)with asymptotic preserving property for the gray radiative transfer equations is constructed in cylindrical coordinates.The current UGKS can naturally capture the radiation diffusion solution in the optically thick regime with the cell size being much larger than photon's mean free path.At the same time,the current UGKS can present accurate solutions in the optically thin regime as well.Moreover,it is a finite volume method with total energy conservation.Due to the scale-dependent time evolution solution for the interface flux evaluation,the scheme can cover multiscale transport mechanism seamlessly.The cylindrical hohlraum tests in inertial confinement fusion are used to validate the current approach,and the solutions are compared with implic让Monte Carlo result. 展开更多
关键词 CYLINDRICAL COORDINATE system GRAY RADIATIVE equations Multiscale transport UNIFIED gas KINETIC scheme
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Mathematical Model and Machining Method for Spiral Flute Rake Faces of Hourglass Worm Gear Hob 预览
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作者 YANG Jie LI Haitao +2 位作者 RUI Chengjie HUANG Yi ZHANG Xiaodi 《南京航空航天大学学报:英文版》 EI CSCD 2019年第3期401-412,共12页
To improve the cutting performance of an hourglass worm gear hob and the accuracy of the resulting worm gear,the rake angles of the teeth on the pitch circle should be reduced.A method of forming the spiral flutes by ... To improve the cutting performance of an hourglass worm gear hob and the accuracy of the resulting worm gear,the rake angles of the teeth on the pitch circle should be reduced.A method of forming the spiral flutes by using a variable transmission ratio was developed.This method ensures that the rake angles on the indexing torus of each tooth are approximately 0°.Based on the gear meshing theory and the hourglass worm forming method,the discretization mathematical model of the rake face of a planar double enveloping worm gear hob was established by using cylindrical generating surface,and the feed parameters for machining the rake face for a variable transmission ratio were obtained.The spiral flute was simulated and the hob was machined on a four axis CNC milling machine.A contourgraph was used to measure the rake angle.The measurement results showed that the proposed method can reduce the absolute value of the rake angle on both sides of the cutting teeth,which can be used for machining the spiral flute rake face of an hourglass worm gear hob. 展开更多
关键词 HOURGLASS WORM gear HOB cylindrical generating surface SPIRAL FLUTE RAKE face RAKE angle
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Nonlinear Vibration Analyses of Cylindrical Shells Composed of Hyperelastic Materials
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作者 Jing Zhang Jie Xu +3 位作者 Xuegang Yuan Hu Ding Datian Niu Wenzheng Zhang 《固体力学学报:英文版》 SCIE EI CSCD 2019年第4期463-482,共20页
The nonlinear vibration problem is studied for a thin-walled rubber cylindrical shell composed of the classical incompressible Mooney-Rivlin material and subjected to a radial harmonic excitation. With the KirchhofF-L... The nonlinear vibration problem is studied for a thin-walled rubber cylindrical shell composed of the classical incompressible Mooney-Rivlin material and subjected to a radial harmonic excitation. With the KirchhofF-Love hypothesis, DonnelFs nonlinear shallow shell theory, hyperelastic constitutive relation, Lagrange equations and small strain hypothesis, a system of nonlinear differential equations describing the large-deflection vibration of the shell is derived. First, the natural frequencies of radial, circumferential and axial vibrations axe studied. Then, based on the bifurcation diagrams and the Poincare sections, the nonlinear behaviors describing the radial vibration of the shell are illustrated. Examining the influences of structural and material parameters on radial vibration of the shell shows that the vibration modes are highly sensitive to the thickness-radius ratio when the ratio is less than a certain critical value. Moreover, in terms of the results of multimodal expansion, it is found that the response of the shell to radial motion is more regular than that without considering the coupling between modes, while there are more phenomena for the uncoupled case. 展开更多
关键词 THIN-WALLED CYLINDRICAL SHELL INCOMPRESSIBLE Mooney-Rivlin material Donnell5s NONLINEAR SHALLOW SHELL theory NONLINEAR vibration
Buckling Optimization of Composite Cylinders for Underwater Vehicle Applications Under Tsai-Wu Failure Criterion Constraint
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作者 沈克纯 潘光 《上海交通大学学报:英文版》 EI 2019年第4期534-544,共11页
An optimization framework is developed to maximize design pressure of composite cylindrical shell subjected to hydrostatic pressure. Genetic algorithm(GA) integrated with numerical analysis is used in the framework to... An optimization framework is developed to maximize design pressure of composite cylindrical shell subjected to hydrostatic pressure. Genetic algorithm(GA) integrated with numerical analysis is used in the framework to find optimal winding pattern of the composite cylinders. As a novelty, unlike other studies only considering buckling, in this study, material failure is taken as design constraint in the optimization problem.Sensitivity analyses are performed to study the effects of design variables on the buckling pressure, material failure pressure and design pressure. Comparative study is carried out to analyze the buoyancy factors of the cylindrical shell made of metal alloys and composites. Results reveal that as the shell thickness of the cylinder increases, the material failure pressure instead of the buckling pressure determines the design pressure. It can be concluded that reliable winding pattern designs can be achieved for composite cylinders under hydrostatic pressure when the Tsai-Wu failure criterion is considered. 展开更多
关键词 OPTIMIZATION composites CYLINDRICAL shell BUCKLING FAILURE
Shaking table test and numerical simulation of an isolated cylindrical latticed shell under multiple-support excitations 预览
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作者 Xue Suduo Shan Mingyue +3 位作者 Li Xiongyan Liang Shuanzhu Huang Fuyun Liu Yi 《地震工程与工程振动:英文版》 SCIE EI CSCD 2019年第3期611-630,共20页
In order to study the infl uence of the ground motion spatial eff ect on the seismic response of large span spatial structures with isolation bearings, a single-layer cylindrical latticed shell scale model with a simi... In order to study the infl uence of the ground motion spatial eff ect on the seismic response of large span spatial structures with isolation bearings, a single-layer cylindrical latticed shell scale model with a similarity ratio of 1/10 was constructed. An earthquake simulation shaking table test on the response under multiple-support excitations was performed with the high-position seismic isolation method using high damping rubber (HDR) bearings. Small-amplitude sinusoidal waves and seismic wave records with various spectral characteristics were applied to the model. The dynamic characteristics of the model and the seismic isolation eff ect on it were analyzed at varying apparent wave velocities, namely infi nitely great, 1000 m/s, 500 m/s and 250 m/s. Besides, numerical simulations were carried out by Matlab software. According to the comparison results, the numerical results agreed well with the experimental data. Moreover, the results showed that the latticed shell roof exhibited a translational motion as a rigid body after the installation of the HDR bearings with a much lower natural frequency, higher damping ratio and only 1/2~1/8 of the acceleration response peak values. Meanwhile, the structural responses and the bearing deformations at the output end of the seismic waves were greatly increased under multiple-support excitations. 展开更多
关键词 SINGLE-LAYER CYLINDRICAL latticed shell HDR bearings seismic isolation multiple-support EXCITATIONS SHAKING table test
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Nonlinear Dynamical Responses of Rotary Cylindrical Shells with Internal Resonance
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作者 Yufei Zhang Jintang Liu Bangchun Wen 《固体力学学报:英文版》 SCIE EI CSCD 2019年第2期186-200,共15页
The nonlinear forced vibration response of a thin, elastic, rotary cylindrical shell to a harmonic excitation is investigated in this study. Nonlinearities due to the large-amplitude shell motion are considered by usi... The nonlinear forced vibration response of a thin, elastic, rotary cylindrical shell to a harmonic excitation is investigated in this study. Nonlinearities due to the large-amplitude shell motion are considered by using Donnelfs nonlinear shallow-shell theory, with consideration of the effect of viscous structural damping. Different from the conventional DonnclFs nonlinear shallow-shell equations, an improved nonlinear model without employing the Airy stress function is utilized to study the nonlinear dynamics of thin shells. The system is discretized using the Galerkin method, while a model involving two degrees of freedom and allowing for the traveling wave response of the shell is adopted. The method of harmonic balance is applied to study the nonlinear dynamic responses of the t wo-degree-of-freedom system. In addition, the st ability of steady-state solutions is analyzed in detail. Finally, results are given for exploring the effects of different parameters on the nonlinear dynamic response with internal resonance. 展开更多
关键词 CYLINDRICAL SHELLS ROTARY Nonlinear vibrations Internal RESONANCE DYNAMICAL response
A Note on the Transformation of Variables of KP Equation, Cylindrical KP Equation and Spherical KP Equation
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作者 刘春平 《理论物理通讯:英文版》 SCIE CAS CSCD 2019年第2期170-174,共5页
In a recent article(Commun. Theor. Phys. 67(2017) 207), three(2+1)-dimensional equations — KP equation, cylindrical KP equation and spherical KP equation, have been reduced to the same Kd V equation by using differen... In a recent article(Commun. Theor. Phys. 67(2017) 207), three(2+1)-dimensional equations — KP equation, cylindrical KP equation and spherical KP equation, have been reduced to the same Kd V equation by using different transformation of variables, respectively. In this short note, by adding an adjustment item to original transformation, three more general transformation of variables corresponding to above three equations have been given.Substituting the solutions of the Kd V equation into our transformation of variables, more new exact solutions of the three(2+1)-dimensional equations can be obtained. 展开更多
关键词 transformation of VARIABLES KP EQUATION CYLINDRICAL KP EQUATION SPHERICAL KP EQUATION
The instability of terahertz plasma waves in cylindrical FET
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作者 李东澳 张丽萍 杜洪梅 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第4期66-69,共4页
In this paper,the Dyakonov-Shur instability of terahertz(THz)plasma waves has been analyzed in gated cylindrical field effect transistor(FET).In the cylindrical FET,the hydrodynamic equations in cylindrical coordinate... In this paper,the Dyakonov-Shur instability of terahertz(THz)plasma waves has been analyzed in gated cylindrical field effect transistor(FET).In the cylindrical FET,the hydrodynamic equations in cylindrical coordinates are used to describe the THz plasma wave in twodimensional electronic gas.The research results show that the oscillation frequency of the THz plasma wave is increased by increasing the component of wave in the circumferential direction,but in stability increment of the THz plasma wave are in creased by increasing the radius of channel. 展开更多
关键词 THZ plasma WAVES CYLINDRICAL field effect transistor oscillation frequency
单向曲率抛物反射面可展结构型面精度误差研究 预览
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作者 李明 李向华 +4 位作者 李波 周鑫 崔琦峰 施飞舟 徐晓辉 《空间电子技术》 2019年第4期83-88,共6页
具备大尺度、高精度特性的刚性反射面天线是解决星载微波遥感有效载荷空间分辨率、增益与信噪比等电气指标需求的优选方案,需要采用可展结构设计,以解决卫星尺寸与整流罩包络之间的矛盾。文章针对高精度单向曲率抛物反射面可展结构型面... 具备大尺度、高精度特性的刚性反射面天线是解决星载微波遥感有效载荷空间分辨率、增益与信噪比等电气指标需求的优选方案,需要采用可展结构设计,以解决卫星尺寸与整流罩包络之间的矛盾。文章针对高精度单向曲率抛物反射面可展结构型面精度误差的分析及预示需求,基于刚体旋转的欧拉理论及正态分布,描述加工精度误差与展开重复精度误差,建立了可展结构型面精度误差的预测模型。并根据Monte Carlo试验结果数据的统计分析方法,开展了面向加工精度误差与展开重复精度误差的敏感度分析。结果表明:板间铰链的展开重复精度对整体型面精度误差的收益高于根部铰链,同等条件下应优先对其进行优化;在整体型面精度误差指标允许的前提下,应适当提高刚性抛物柱面的加工精度误差,从而控制整体型面精度误差的变化区间。 展开更多
关键词 单向曲率 抛物反射面 刚性反射面 型面精度误差 MONTE CARLO方法
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Indexes of Tree Structure of Cylindrical Pear Orchards at the Sapling Stage 预览
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作者 Shuwei WEI Shaomin WANG +1 位作者 Ran DONG Xiaochang DONG 《农业生物技术:英文版》 CAS 2019年第3期145-146,共2页
The reasonable tree and population structure parameters of various cylindrical pear orchards were studied.The results showed that for 3-year-old ‘Xinli No.7’,the tree height was 3.48 m,and the trunk height was 63 cm... The reasonable tree and population structure parameters of various cylindrical pear orchards were studied.The results showed that for 3-year-old ‘Xinli No.7’,the tree height was 3.48 m,and the trunk height was 63 cm;there were 63 branches per plant,which was equivalent to 19 971 branches per 667 m^2;the leaf area index was 1.62.For the 3-year-old ‘Xueqing’,the tree height was 3.03 m,and the trunk height was 74 cm;the number of branches per plant was 57,which was equivalent to 18 069 branches per 667 m^2;the leaf area index was 1.73.The cylindrical trees of the two varieties had the following characteristics: the canopy structure was tight;the branches were equally distributed,and the number of medium branches and short branches accounted for more than 60% of the total number of branches of the whole plant. 展开更多
关键词 PEAR SAPLING CYLINDRICAL
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Use of incipient motion data for backward erosion piping models 预览
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作者 Vera M. van Beek Bryant A. Robbins +2 位作者 Gijs J.C.M. Hoffmans Adam Bezuijen Leo C. van Rijn 《国际泥沙研究:英文版》 SCIE 2019年第5期401-408,共8页
Backward erosion piping involves the gradual removal of granular material under the action of water flow from the foundation of a dam or levee, whereby shallow pipes are formed that grow in the direction opposite to t... Backward erosion piping involves the gradual removal of granular material under the action of water flow from the foundation of a dam or levee, whereby shallow pipes are formed that grow in the direction opposite to the flow. This pipe-forming process can ultimately lead to failure of a water-retaining structure and is considered one of the most important failure mechanisms for dikes and levees in the Netherlands and the United States. Modeling of this mechanism requires the assessment of hydraulic conditions in the pipe, which are controlled by the particle equilibrium at the pipe wall. Since the pipe's dimensions are controlled by the inflow to the pipe from the porous medium, the flow through the pipe is thought to be laminar for fine- to medium-grained sands. The literature provides data for incipient motion in laminar flow, which is reviewed here and complemented with data from backward erosion experiments. The experiments illustrate the applicability of the laminar incipient motion data to determine the erosion pipe dimensions and corresponding pipe hydraulics for fine- to medium-grained sands, for the purpose of backward erosion piping modeling. 展开更多
关键词 Internal EROSION BACKWARD EROSION PIPING CYLINDRICAL test Incipient motion DIKES LEVEES
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Geometric optimization model for the solar cavity receiver with helical pipe at different solar radiation
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作者 Chongzhe ZOU Huayi FENG +3 位作者 Yanping ZHANG Quentin FALCOZ Cheng ZHANG Wei GAO 《能源前沿:英文版》 CSCD 2019年第2期284-295,共12页
In consideration of geometric parameters, several researches have already optimized the thermal efficiency of the cylindrical cavity receiver. However, most of the optimal results have been achieved at a fixed solar r... In consideration of geometric parameters, several researches have already optimized the thermal efficiency of the cylindrical cavity receiver. However, most of the optimal results have been achieved at a fixed solar radiation. At different direct normal irradiance (DNI), any single optimal result may not be suitable enough for different regions over the world. This study constructed a 3-D numerical model of cylindrical cavity receiver with DNI variation. In the model of a cylindrical cavity receiver containing a helical pipe, the heat losses of the cavity and heat transfer of working medium were also taken into account. The simulation results show that for a particular DNI in the range of 400 W/m2 to 800 W/m2, there exists a best design for achieving a highest thermal efficiency of the cavity receiver. Besides, for a receiver in constant geometric parameters, the total heat losses increases dramatically with the DNI increasing in that range, as well as the temperature of the working medium. The thermal efficiency presented a different variation tendency with the heat losses, which is 2.45% as a minimum decline. In summary, this paper proposed an optimization method in the form of a bunch of fitting curves which could be applied to receiver design in different DNI regions, with comparatively appropriate thermal performances. 展开更多
关键词 cylindrical CAVITY RECEIVER 3-D numerical simulation GEOMETRIC optimization direct normal irradia-tion
Hermitian Yang—Mills Metrics on Higgs Bundles over Asymptotically Cylindrical Kahler Manifolds
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作者 Pan ZHANG 《数学学报:英文版》 SCIE CSCD 2019年第7期1128-1142,共15页
Let V be an asymptotically cylindrical Kahler manifold with asymptotic cross-section ■. Let (E■,Φ■)be a st able Higgs bundle over ■, and (E,Φ) a Higgs bundle over V which is asymptotic to (E■,Φ■). In this pap... Let V be an asymptotically cylindrical Kahler manifold with asymptotic cross-section ■. Let (E■,Φ■)be a st able Higgs bundle over ■, and (E,Φ) a Higgs bundle over V which is asymptotic to (E■,Φ■). In this paper, using the continuity method of Uhlenbeck and Yau, we prove that there exists an asymptotically translation-invariant projectively Hermitian Yang-Mills metric on (E,Φ). 展开更多
关键词 HIGGS bundles ASYMPTOTICALLY CYLINDRICAL KAHLER manifolds HERMITIAN YANG-MILLS metrics
Vector mode based optical direct detection orthogonal frequency division multiplexing transmission in short-reach optical link
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作者 Jianping LI Zhaohui LI 《中国光电子学前沿:英文版》 EI CSCD 2019年第1期41-51,共11页
As one solution to implement the largecapacity space division multiplexing(SDM)transmission systems,the mode division multiplexing(MDM)has gained much attention recently.The vector mode(VM),which is the eigenmode of t... As one solution to implement the largecapacity space division multiplexing(SDM)transmission systems,the mode division multiplexing(MDM)has gained much attention recently.The vector mode(VM),which is the eigenmode of the optical fiber,has also been adopted to realize the optical communications including the transmission over free-space optical(FSO)and optical fiber links.Considering the concerns on the short-reach optical interconnects,the low cost and high integration technologies should be developed.Direct detection(DD)with higher-order modulation formats in combination of MDM technologies could offer an available trade-off in system performance and complexity.We review demonstrations of FSO and fiber high-speed data transmission based on the VM MDM(VMDM)technologies.The special VMs,cylindrical vector beams(CVB),have been generated by the q-plate(QP)and characterized accordingly.And then they were used to implement the VMDM transmission with direct-detection orthogonal frequency division multiplexing(DD-OFDM).These demonstrations show the potential of VMDM-DD-OFDM technology in the large-capacity short-reach transmission links. 展开更多
关键词 space DIVISION MULTIPLEXING (SDM) MODE DIVISION MULTIPLEXING (MDM) few-mode fiber (FMF) VECTOR MODE (VM) cylindrical VECTOR beam (CVB) orthogonal frequency DIVISION MULTIPLEXING (OFDM) direct detection (DD) OPTICAL interconnect
Real-time calculation of fragment velocity for cylindrical warheads 预览
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作者 David Felix Ian Colwill Elias Stipidis 《Defence Technology(防务技术)》 CAS CSCD 2019年第3期264-271,共8页
To simulate explosion fragments, it is necessary to predict many variables such as fragment velocity, size distribution and projection angle. For active protection systems these predictions need to be made very quickl... To simulate explosion fragments, it is necessary to predict many variables such as fragment velocity, size distribution and projection angle. For active protection systems these predictions need to be made very quickly, before the weapon hits the target. Fast predictions also need to be made in real time simulations when the impact of many different computer models need to be assessed. The research presented in this paper focuses on creating a fast and accurate estimate of one of these variables - the initial fragment velocity. The Gurney equation was the first equation to calculate initial fragment velocity. This equation, sometimes with modifications, is still used today where finite element analysis or complex mathematical approaches are considered too computationally expensive. This paper enhances and improves Breech’s two-dimensional Gurney equation using available empirical data and the principals of conservation of momentum and energy. The results are computationally quick, providing improved accuracy for estimating initial fragment velocity. This will allow the developed model to be available for real-time simulation and fast computation, with improved accuracy when compared to existing approaches. 展开更多
关键词 INITIAL FRAGMENT VELOCITY REAL-TIME SIMULATION CYLINDRICAL explosion
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Finite element modeling of counter-roller spinning for large-sized aluminum alloy cylindrical parts
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作者 Dawei ZHANG Fan LI +1 位作者 Shuaipeng LI Shengdun ZHAO 《机械工程前沿:英文版》 CSCD 2019年第3期351-357,共7页
Counter-roller spinning (CRS), where the mandrel is replaced by rollers, is an effective means of manufacturing large-sized, thin-walled, cylindrical parts with more than 2500 mm diameter. CRS is very complex because ... Counter-roller spinning (CRS), where the mandrel is replaced by rollers, is an effective means of manufacturing large-sized, thin-walled, cylindrical parts with more than 2500 mm diameter. CRS is very complex because of multi-axis rotation, multi-local loading along the circumference, and radial-axial compound deformation. Analytical or experimental methods cannot fully understand CRS. Meanwhile, numerical simulation is an adequate approach to investigate CRS with comprehensive understanding and a low cost. Thus, a finite element (FE) model of CRS was developed with the FORGE code via meshing technology, material modeling, determining the friction condition, and so on. The local fine mesh moving with the roller is one of highlights of the model. The developed 3D-FE model was validated through a CRS experiment by using a tubular blank with a 720 mm outer diameter. The developed 3D-FE model of CRS can provide a basis for parameter optimization, process control, die design, and so on. The data on force and energy predicted by the 3D-FE model can offer reasonable suggestions for determining the main mechanical parameters of CRS machines and selecting the motors. With the predicted data, an all-electric servo-drive system/machine with distributed power was designed in this work for CRS with four pairs of rollers to manufacture a large-sized, thinwalled, cylindrical part with 6000 mm diameter. 展开更多
关键词 large-sized CYLINDRICAL part counter-roller SPINNING aluminum alloy finite element method distributed power
Passively Q-switched cylindrical vector laser based on a black phosphorus saturable absorber
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作者 贺志文 郑杨 +5 位作者 刘宏燕 李铭坤 陆华 张何泽 冯晴亮 毛东 《中国光学快报:英文版》 SCIE EI CAS CSCD 2019年第2期16-20,共5页
We demonstrate an all-fiber Q-switched cylindrical vector laser based on a black phosphorus saturable absorber and a transverse mode converter. The saturable absorber is prepared by incorporating the polyvinyl alcohol... We demonstrate an all-fiber Q-switched cylindrical vector laser based on a black phosphorus saturable absorber and a transverse mode converter. The saturable absorber is prepared by incorporating the polyvinyl alcohol with anti-oxidized black phosphorus nanosheets exfoliated in aqueous poly(dimethyldiallyl ammonium chloride)solution. The mode converter is composed of a tapered two-mode fiber and a single-mode fiber, and it can excite switchable azimuthally and radially polarized beams by modulating the input polarization. By enhancing the pump power from 64.68 to 174.82 mW, the repetition rate of the Q-switched azimuthally/radially polarized laser enlarges from 16.72/19.25 to 30.71/37.82 kHz. 展开更多
关键词 Passively Q-SWITCHED CYLINDRICAL
3D fracture modelling and limit state analysis of prestressed composite concrete pipes
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作者 Pengfei HE Yang SHEN +1 位作者 Yun GU Pangyong SHEN 《结构与土木工程前沿:英文版》 EI CSCD 2019年第1期165-175,共11页
In this manuscript,we study fracture of prestressed cylindrical concrete pipes.Such concrete pipes play a major role in tunneling and underground engineering.The structure is modelled fully in 3D using three-dimension... In this manuscript,we study fracture of prestressed cylindrical concrete pipes.Such concrete pipes play a major role in tunneling and underground engineering.The structure is modelled fully in 3D using three-dimensional continuum elements for the concrete structure which beam elements are employed to model the reinforcement.This allows the method to capture important phenomena compared to a pure shell model of concrete.A continuous approach to fracture is chosen when concrete is subjected to compressive loading while a combined continuous-discrete fracture method is employed in tension.The model is validated through comparisons with experimental data. 展开更多
关键词 cylindrical CONCRETE structures LIMIT state ANALYSIS 3D fracture modelling PRESTRESSED COMPOSITE pipes reinforced CONCRETE three-point BENDING test
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