弹性介质中多孔石墨烯增强复合材料截锥壳的振动

Vibration of Graphene Reinforced Porous Truncated Conical Composite Shells in Elastic Medium

为研究弹性介质中含内部孔隙的石墨烯增强功能截锥壳的振动特性,根据孔隙的分布假定孔隙的体积组分,用混合率和Halpin-Tsai微观力学模型计算石墨烯增强材料的物性参数。基于Donnel经典薄壳理论和Hamilton变分原理建立了振动的控制方程并求解,讨论了孔隙、石墨烯和弹性介质对振动特性的影响。结果表明:与孔隙分布类型相比,孔隙系数对振动频率和动力响应的影响更大。在孔隙分布同为中间多、内侧和外侧少的情况下,石墨烯质量分数从0%提高到0.6%时,石墨烯为内外侧多、中间少分布的最大动挠度减小45.66%,而外侧少、中间多分布的最大动挠度减小36.83%。可见,为提高圆锥壳的有效刚度,石墨烯纳米片应该更多地布置在圆锥壳的内侧和外侧部位。

To study the vibration of functionally graded graphene platelets(FG-GPLs)reinforced truncated conical composite shells in elastic medium,the pore volume fraction with different porosity distributions were assumed to evaluate the material properties by using Halpin-Tsai micromechanical model and the law of mixture.Based on Donnel’s classic shell theory and Hamilton principle,the governing equations of the vibration for the shells were built and solved.The effects of internal pores,GPLs,and elastic medium on the vibration characteristics were discussed in detail.The results show that the effects of pore coefficient on the natural frequency and transient responses are more significant than those of porosity distribution.In the condition that pores are more distribucted in the middle of the shell,the maximum transient deflection of the shell with mores graphene platelets in the inner and outer surfaces is decreased by 45.66%as the graphene content rises from 0%to 0.6%.Nevertheless,for the shell with more graphene platelets in the middle area,the maximum transient deflection is decreased by 36.83%.Hence,more graphene platelets should be distributed in the inner and outer area of the conical shell to increase the effective stiffness of the shell.