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ZHUHuai－liang 《上海大学学报(英文版)》2001,5(1):35-39
In this paper ,a hybrid approach was developed to investigate the transient responses of a multi-span non-uniform flexble spinning shaft with nonlinear and asymmetric supports.The non-uniform spinning shaft with variable parmeters was modeled as a Bernoulli-Euler beam column with sectional constant cross-section properties by the finite element method.The supporting stiffness behavior of the nonlinear supports was described as a piecewise-linear and asymmetric model.The equations of motion in the matrix form of a multi-span non-uniform spinning shaft with nonlinear and asymmetric supports were formulated using Hamilton‘s principle and the assumed mode method.As an example,a spinning rocket with many variable stiffness supports was numerically simulated by the direct integration method.The transient response and dynamic behavior of this rotate-dynamic system are analyzed. 相似文献
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数字博物馆就是采用数字模拟物品和真实场景来展示历史、科学和艺术。它是传统的技术与先进的计算机虚拟技术的结合,以交互探索形式向观众展示的历史事件、文字、图片、文物、场景。参观者可以随时随地的对感兴趣的事物进行详细的参观了解,对相关的图片、文字说明进行认真的阅读分析和下载。用户可以使用一个鼠标（跟踪器）随意在各个展室行走、驻足每个展位,甚至可以深人展示物体内部,了解内部结构材质并追求历史再现、观看它的制造过程。人们不仅可以看到物品的三维模型,而且可以在计算机虚拟世界中进行观赏。 相似文献
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To observe the inner operating process of distance protection, a Matlab/Simulink based dynamic simulation system for microprocessor-based distance protection is designed in this pa- per. As a modularized design, the simulation system is composed of several modules such as fault transient calculation, startup, Fourier algorithm, phase selection, impedance computing and im- pedance comparison etc. Some typical simulation cases, which focus on the main factors affect- ing distance relay's operation, have been simulated with the system. Simulation results show that the system is able to demonstrate the dynamic behaviors of distance protection under different op- erating conditions. 相似文献
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The design of a segmented-rod projectile is often simplified into an ideal one in theoretical analysis for the convenience of modeling of its performance. But the actual performance of non-ideal segmented-rod projectiles over the impact velocity range in practical applications was rarely explored. AUTODYN numerical code is used to investigate the influence of the component design upon the penetration performance of non-ideal segmented-rod projectiles over a wide range of impact velocities, which can be used to guide the optimal design of weaponry segmented-rod projectiles. 相似文献
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Many engineering materials demonstrate dynamic enhancement of their compressive strength with the increase of strain-rate, which have been included in material models to improve the reliability of numerical simulations of the material and structural responses under impact and blast loads. The strain-rate effects on the dynamic compressive strength of a range of engineering materials which behave in hydrostatic-stress-sensitive manner were investigated. It is concluded that the dynamic enhancement of the compressive strength of a hydrostatic-stress-sensitive material may include inertia-induced lateral confinement effects, which, as a non-strain-rate factor, may greatly enhance the compressive strength of these materials. Some empirical formulae based on the dynamic stress-strain measurements over-predict the strain-rate effects on the compressive strength of these hydrostatic-stress-sensitive materials, and thus may over-estimate the structural resistance to impact and blast loads, leading to non-conservative design of protective structures. 相似文献
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INTRODUCTION Turbulent gas-particle flows are frequently found in natural phenomena and industrial processes.Cases of cylinders in cross flows with particles occur in heat exchange equipment,including the convective zone of a fluidized-bed combustor,and in the primary superheaters,reheaters,and economizers of coal-fired boilers.Coherent structures often occur in the above-mentioned gas-particle flow,and have great effect on such different systems,while some features of tur-bulent multiphas… 相似文献
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MA Guowei YE Ziqing ZHANG Xingui 《天津大学学报(英文版)》2006,12(B09):122-125
Two numerical simulations were performed to investigate the protective effect of the foam cladding. One simulation is based on a previous experimental study, which is a ballistic pendulum with and without a foam cladding subjected to close-range blast loading. The other model is a steel beam with and without a foam cladding under blast loading. The overpressure due to the blast event can be calculated by the empirical function ConWep or by an arbitrary Lagrangian-Eulerian （ALE） coupling model. The first approach is relatively simple and widely used. The second approach can model the propagation of the blast wave in the air and the interaction between the air and the solid. It is found that the pendulum with the foam cladding always swings to a larger rotation angel compared to a bare pendulum. However, the steel beam with an appropriate foam cladding has a smaller deflection compared to the bare beam without a foam cladding. It is concluded that the protective effect of the foam cladding depends on the properties of the foam and the protected structure. 相似文献
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江西人民广播电台（以下简称“江西电台”）总控系统项目是江西电台技术人员在西班牙AEQ公司专业数字音频设备基础上,结合实际情况自行设计和二次开发的电台总控系统。该系统采用数字模拟兼容调音台、切换矩阵以及相关的周边设备,在每个直播室到总控机房间,构建了4路模拟和2路数字立体声通路,能完全满足江西电台6套节目的播出、信号切换、转播、监测、记录、停播报警和自动垫乐等全套功能需求。 相似文献
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HUAN Shi JIANG Guoping Chen Shengming TANG Xiangqian 《天津大学学报(英文版)》2006,12(B09):158-160
The grisliness after-effects can be induced by explosion accident with the collapsing of the structures, the demolishing of the equipments and the casualty of the human beings. Isolation belt constructed between the blast point and the construction is one of the useful design schemes for blast resistance. The nonlinear procedure ANSYS/LSDYNA970 is used to simulate the contact detonation and the isolation belt of blast resistance filled with the air or water respectively. The results indicate that the maximal damage can be caused by the contact detonation, and the isolation belt of blast resistent filled with water can reduce the damage greatly. 相似文献