Numerical Simulations on Buckling Failure of Preloaded Cylindrical Shell Irradiated by High Power Laser Beam
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摘要: 采用有限元方法(ANSYS7.0)和简易的热力耦合本构关系,较系统地数值研究了预载柱壳受激光辐照时的热力响应和热屈曲失效行为,分析了几种壳体在不同预载条件下(轴压或内压)的屈曲模态和屈曲特征值,给出了屈曲模态和热屈曲失效与激光强度、辐照时间、预载条件和壳体几何尺度及形状间的定量或定性关系。计算结果表明:(1)屈曲失效行为主要集中在激光辐照区内且以径向屈曲为主。(2)在一定范围内,屈曲特征值与光斑中心点温度近似有线性关系。(3)激光辐照区内高温引起的材料软化和预载径向变形的耦合作用是柱壳发生热屈曲失效的根本原因,有效提高结构刚度,可使屈曲特征值提高。(4)壳体形状的改变对内压柱壳有更为明显的影响,其中圆柱形壳体屈曲特征值最大,因此具有较高的安全性。Abstract: With finite-element software ANSYS 7.0 and simple thermal-mechanical coupling constitutive relations, the buckling failure of preloaded shell irradiated by high power laser beam was studied by numerical simulations. Buckling mode and buckling critical loading were analysed for different preloading conditions. The influences of laser intensity, beam irradiation time, preloading conditions, shape and geometric parameters of shell on the buckling mode were discussed. The numerical results showed that: (1) the buckling deformation of the shell was concentrated on the area of laser spot and the radial buckling was the main buckling mode, (2) a linear relationship between buckling eigenvalue and the maximum temperature at the center of laser spot was approached, (3) the buckling failure of shell was attributed to the coupling effect of the material softenning and the radial deformation in the laser spot, and hence to raise the stiffness of the material would enhance the ability of anti-irradiation of structure substantially, (4) the effect was more obvious under internal preloading for different shapes of shell, and the cylindrical shell had larger buckling eigenvalue and higher security.
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Key words:
- cylindrical shell /
- buckling /
- finite element /
- irradiated by high power laser beam
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