A size-dependent exact theory for thermal buckling, free and forced vibration analysis of temperature dependent FG multilayer GPLRC composite nanostructures restring on elastic foundation
A size-dependent exact theory for thermal buckling, free and forced vibration analysis of temperature dependent FG multilayer GPLRC composite nanostructures restring on elastic foundation
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DOI：
10.1007/s10999-018-9431-8
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发表时间：
2019-09-01
影响因子：
3.7
通讯作者：
Habibi, Mostafa
中科院分区：
文献类型：
--
作者：
Safarpour, Hamed;Hajilak, Zanyar Esmailpoor;Habibi, Mostafa
本文研究了尺寸相关的石墨烯片材增强复合材料纳米圆柱壳的热屈曲和自由/强迫振动特性。此外，纳米壳被嵌入弹性Pasternak介质中，该弹性Pasternak介质是通过在Winkler模型中添加剪切层而获得的。本文提出的纳米谐振器是基于一阶纳米级圆柱壳在横向压力作用下的振动。假设分段功能梯度石墨烯增强复合材料(FG-GRC)在柱面纳米壳层厚度方向上呈梯度分布，并通过纳米力学模型对其材料性能进行了估算。并利用Halpin-Tsai纳米力学模型推测了各层的有效材料性质。采用修正的偶应力参数分析了FG-GRCs纳米壳的尺寸效应。本研究的创新之处在于，除了考虑尺寸效应外，还考虑了FG-GRCs和热效应对FG-GRCs纳米壳的共振频率、热屈曲和动态挠度的影响。利用哈密顿原理建立了控制方程和边界条件，并用解析法进行了求解。结果表明，GPL分布方式、修正的偶应力参数、长径比、振型数、Winkler系数和热环境对FG-GRC圆柱纳米壳在热环境中的共振频率、相对频率变化、热屈曲和动态挠度有重要影响。
In this paper, thermal buckling and free/forced vibration characteristics of size-dependent composite cylindrical nanoshell reinforced with graphene platelets (GPLs) is presented. Also, the nanoshell is embedded in an elastic pasternak medium, which is obtained by adding a shear layer to the Winkler model. The present nano-resonator is based on a vibrating first order nanoscale cylindrical shell subjected to transverse pressure. The temperature-dependent material properties of piece-wise functionally graded graphene-reinforced composites (FG-GRCs) are assumed to be graded in the thickness direction of a cylindrical nanoshell and are estimated through a nanomechanical model. Also, Halpin-Tsai nanomechanical model in used to surmise the effective material properties of each layer. The size-dependent FG-GRCs nanoshell is analyzed using modified couple stress parameter. The novelty of the current study is in considering the effects of FG-GRCs and thermal in addition of size effect on resonance frequencies, thermal buckling and dynamic deflections of the FG-GRCs nanoshell. The governing equations and boundary conditions have been developed using Hamilton's principle and have been solved with the aid of analytical method. The results show that, GPL distribution pattern, modified couple stress parameter, length to radius ratio, mode number, winkler coefficient and thermal environment have important role on resonance frequency, relative frequency change, thermal buckling and dynamic deflections of the FG-GRCs cylindrical nanoshell in thermal environments.