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对钢质和铜质金属圆柱壳的轴向冲击动力响应进行了实验研究,记录了两种不同材料圆柱壳在大质量低速冲击下的冲击力时程曲线,得到其屈曲模态。采用高速摄像及模拟技术给出了钢质圆柱壳渐进屈曲的全过程,为理解钢质圆柱壳的屈曲机理提供了直观的结果。黄铜质圆柱壳在大质量低速冲击下, 出现整个壳面滿布屈曲波纹的塑性动力屈曲现象,说明高速冲击不是产生塑性动力屈曲的充要条件。像铜这样具有高密度的韧性材料,在大质量低速冲击下,会在轴向产生持续的压缩塑性流作用而出现塑性动力屈曲现象。 相似文献
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In the present paper the propagation property of nonlinear waves in a thin viscoelastic tube filled with incom-pressible inviscid fluid is studied.The tube is considered to be made of an incompressible isotropic viscoelastic material described by Kelvin-Voigt model.Using the mass conservation and the momentum theorem of the fluid and radial dynamic equilibrium of an element of the tube wall,a set of nonlinear partial differential equations governing the prop-agation of nonlinear pressure wave in the solid-liquid coupled system is obtained.In the long-wave approximation the nonlinear far-field equations can be derived employing the reductive perturbation technique (RPT).Selecting the expo-nent α of the perturbation parameter in Gardner-Morikawa transformation according to the order of viscous coefficient η,three kinds of evolution equations with soliton solution,i.e.Korteweg-de Vries (KdV)-Burgers,KdV and Burgers equations are deduced.By means of the method of traveling-wave solution and numerical calculation,the propagation properties of solitary waves corresponding with these evolution equations are analysed in detail.Finally,as a example of practical application,the propagation of pressure pulses in large blood vessels is discussed. 相似文献
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利用Ham ilton变分原理,导出了计及有限变形和横向Possion效应的弹性杆中非线性纵向波动方程.利用Jacob i椭圆正弦函数展开和第三类Jacob i椭圆函数展开法,对该方程和截断的非线性方程进行求解,得到了非线性波动方程的两类准确周期解及相应的孤波解和冲击波解,讨论了这些解存在的必要条件. 相似文献
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A new nonlinear wave equation of a finite deformation elastic circular rod simultaneously introducing transverse inertia and shearing strain was derived by means of Hamilton principle. The nonlinear equation includes two nonlinear terms caused by finite deformation and double geometric dispersion effects caused by transverse inertia and transverse shearing strain. Nonlinear wave equation and corresponding truncated nonlinear wave equation were solved by the hyperbolic secant function finite expansion method. The solitary wave solutions of these nonlinear equations were obtained. The necessary condition of these solutions existence was given also. 相似文献
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利用有限变形理论的Lagrange描述,借助非保守系统的Hamilton型变分原理,导出了描述弹性杆中几何非线性波的波动方程· 为了使非线性波动方程有稳定的行波解,计及了粘性效应引入的耗散和横向惯性效应导致的几何弥散· 运用多重尺度法将非线性波动方程简化为KdV_Berg ers方程,这个方程在相平面上对应着异宿鞍-焦轨道,其解为振荡孤波解· 如果略去粘性效应或横向惯性,方程将分别退化为KdV方程或Bergers方程,由此得到孤波解或冲击波解,它们在相平面上对应着同宿轨道或异宿轨道· 相似文献