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戴婷, 戴宏亮, 李军剑, 贺其. 含孔隙变厚度FG圆板的湿热力学响应[J]. 力学学报, 2019, 51(2): 512-523. DOI: 10.6052/0459-1879-18-280
引用本文: 戴婷, 戴宏亮, 李军剑, 贺其. 含孔隙变厚度FG圆板的湿热力学响应[J]. 力学学报, 2019, 51(2): 512-523. DOI: 10.6052/0459-1879-18-280
Ting Dai, Hongliang Dai, Junjian Li, Qi He. HYGROTHERMAL MECHANICAL BEHAVIOR OF A FG CIRCULAR PLATE WITH VARIABLE THICKNESS[J]. Chinese Journal of Theoretical and Applied Mechanics, 2019, 51(2): 512-523. DOI: 10.6052/0459-1879-18-280
Citation: Ting Dai, Hongliang Dai, Junjian Li, Qi He. HYGROTHERMAL MECHANICAL BEHAVIOR OF A FG CIRCULAR PLATE WITH VARIABLE THICKNESS[J]. Chinese Journal of Theoretical and Applied Mechanics, 2019, 51(2): 512-523. DOI: 10.6052/0459-1879-18-280

含孔隙变厚度FG圆板的湿热力学响应

HYGROTHERMAL MECHANICAL BEHAVIOR OF A FG CIRCULAR PLATE WITH VARIABLE THICKNESS

  • 摘要: 功能梯度材料(functionally graded materials, FGM)是组份含量按特定方向连续变化的非均匀复合材料,可有效解决传统复合材料组份之间结合能力弱和不同组份性能难以协调等问题,达到诸如缓和应力集中和优化应力分布等效果,使整体材料在保持细观结构完整性的同时充分发挥各组份材料的性能优势.由于制备技术等原因或出于特殊功能的需要,微孔或孔隙是各类型FGM中的常见缺陷.从细观结构上看,多孔FGM中的孔隙包含了单一组份内的材料孔隙和组份微粒间的结构间隙,这些孔隙将对FGM的力学性能,尤其是在湿热环境下的力学行为产生影响.本文考虑FGM中的两类细观孔隙(材料孔隙和结构孔隙),提出了令各类孔隙依赖于各自组份变化,再线性叠加得到的整体孔隙计算式.考虑组份材料和孔隙填充物(液相水和水蒸气)性质的温度相关性,建立了湿热相关FGM材料模型.针对厚度沿径向变化的旋转圆板结构,应用该FGM材料模型,推导了圆板的非线性稳态湿热控制方程及考虑湿热弹性本构的位移控制方程,采用微分求积法(differential quadrature method,DQM),获得了圆板的湿热场、位移场和应力分布.在数值算例中,利用退化模型的解析解对本文的数值计算方法进行了验证,继而通过改变各关键参数,讨论了两类孔隙率、梯度指数和圆板厚度变化对含孔隙FGM变厚度旋转圆板湿热力学响应的影响规律.

     

    Abstract: Functionally graded materials (FGMs) are composed of two or more discrete constituent phases with continuous and smoothly varying components. Due to the distinctive merit comparing with usual composite materials that they can reduce the stress concentration and optimize the stress distribution to make good use of each component, utilizing of FGMs helps to resolve some problems in composite materials such as low bond strength and inharmonious of properties effectively. Because of the preparation technology or for the need of special structures, micropores or pores are commonly found in various types of FGM and play an important role in the influence factors on mechanical properties of FGMs. In addition, the application conditions of FGMs are usually complex or extreme with multiple physical fields, and the mechanical responses of various FGMs under coupling multi-fields will be more complex. On micro scale, the pores in porous FGM include material pores of each components and structural gaps between different particles. These pores will affect the properties of FGM, especially under hygrothermal environments. In this paper, two kinds of micro pores (material pores and structural gaps) in FGM are both considered. An expression to characterize porosity of the whole FGM is proposed, where the porosity of each component is related to its volume fraction and the global porosity is a linear superposition. Considering temperature dependency of the component properties as well as the material properties of pore fillers (liquid water or vapor), a prediction model of the porous FGM is established. Focusing on a rotating circular plate with its thickness varying along the radial direction, and applying the current porous FGM model, governing equations of the nonlinear steady-state temperature and moisture fields as well as displacement field are derived. Solving the governing equations by the differential quadrature method (DQM), distributions of temperature, moisture, displacement and stress of the FG circular plate are obtained. In the numerical examples, analytic solution of a simplified mechanical model is carried out to verify the numerical calculation process of the current study. By changing the key parameters, influences of each porosity, gradient index and thickness change rule on the hygrothermal mechanical responses of the porous FG circular plate with variable thickness are discussed in detail.

     

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