On the Critical Velocity of the Sandwich Cylindrical Shell to Moving Internal Pressure
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摘要: 基于夹层壳理论和三维弹性动力学理论,研究了无限长夹层圆柱壳在移动内压作用下的临界速度.首先,基于夹层壳理论,考虑夹芯的压缩和剪切变形以及面板的剪切变形,研究了轴对称简谐波在无限长夹层圆柱壳中的传播问题;其次,基于三维弹性动力学理论,将位移变量用Legendre正交多项式系表示,同时引入位置相关函数,将求解导波问题化为简单的特征值问题.利用这两种方法得到了最低模态的频散曲线,最小相速便是内压移动的临界速度.最后,用算例和数值模拟来验证方法的有效性.结果表明,两种理论得到临界速度吻合得较好;当波数较小时,两种理论得到的频散曲线吻合得很好,当k→∞时,夹层壳理论和弹性动力学理论得到的极限相速分别趋于面板和夹芯的剪切波波速.波数较小时,两种理论分析夹层圆柱壳的导波问题是有效的.数值模拟预测的临界速度与理论分析的结果吻合得很好.
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关键词:
- 夹层圆柱壳 /
- 临界速度 /
- 夹层壳理论 /
- 弹性动力学 /
- Legendre正交多项式
Abstract: The critical velocity of the infinite long sandwich shell to moving internal pressure is studied using sandwich shell theory and elastodynamics theory.Firstly the propagation of axisymmetric free harmonic waves in the sandwich shell was studied using sandwich shell theory considering the compressibility of core and the transverse shear deformation of core and face sheets.Secondly on the basis of elastodynamics theory,the displacement components expanded by Legendre polynomials,as well as position-dependent elastic constants and densities were introduced into the equations of motion.The critical velocity is the minimum phase velocity on the desperation relation curve obtained using the two methods.Finally the numerical ex amples and FE simulations were executed.Results show that the tow critical velocities agree well with each other,and two desperation relation curves agree well with each other when wave number k is relatively small;however two limit phase velocities approach the shear wave velocities of the face sheet and the core respectively when k limits to infinite.The two methods are efficient to investigate wave propagation in the sandwich cylindrical shell,when k is relatively small.The critical velocity predicted by FE simulations agrees well with that predicted by theoretical analysis. -
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