舰船复合材料构件非线性行为和动力特性多尺度建模与分析

In the recent years, fiber reinforced composite (FRC) laminated structures are widely used in marine structures. Functionally graded materials (FGMs) are a new generation of composite materials in which the microstructural details are spatially varied through nonuniform distribution of the reinforcement phase. Two kinds of FGMs are designed to improve mechanical behavior of plate/shell structures. One is the functionally graded particles reinforced composite, like functionally graded ceramic-metal materials. Another one is the functionally graded unidirectional fibers reinforced composite. The concept of functionally graded material can be utilized for the laminates by non-homogeneous distribution of fiber reinforcements into the matrix with a specific gradient so that the mechanical behavior of laminated plate/shell structures can be improved. Like the functionally graded ceramic-metal materials, the material properties of functionally graded fiber reinforced composites (FG-FRCs) may be dependent of temperature..On the other hand, one of the recent advances in material and structural engineering is in the field of smart structures which incorporates adaptive materials. Piezoelectric materials are also extensively used in marine structures in the quest for lightweight flexible structures with self-controlling and/or self-monitoring capabilities. Piezoelectric fiber reinforced composites (PFRCs) have the potential to provide various sensing functions for nondestructive testing and may be used as sensing elements for structural health monitoring and adaptive material systems. By taking advantage of the direct and converse piezoelectric effects, hybrid composite structures with piezoelectric fiber reinforced composite actuators can adapt harsh environmental condition by combining the traditional advantages of composite laminates with the inherent capability of piezoelectric materials..We propose a multi-scale approach to model and analysis the nonlinear bending, postbuckling behaviors and nonlinear dynamic responses of FG-FRC plate/shell structures with or without PFRC actuators. From which the material properties of FRCs and PFRCs are estimated based on the micromechanical model and the governing equations of plate/shell structures are formulated based on the higher order shear deformation theory. The novel contribution of the present work is that both material property gradient and temperature-dependent material properties are taken into consideration in the nonlinear analyses. Numerical examples are carried out for different geometric and physical parameters and loading conditions, e.g. mechanical, thermal, electrical loads and their combination. The results presented explore for the first time the important issue of FG-FRC plate/shell structures, and thus are greatly helpful to understanding for engineering design.

功能梯度材料是新一代的复合材料，其增强体在微观上呈非均匀分布。有两类功能梯度复合材料。一类是颗粒增强功能梯度复合材料。另一类是纤维增强功能梯度复合材料。将功能梯度材料的概念用于纤维增强复合材料层合结构，将增强纤维在基体中按一定的方式非均匀排布，从而使层合板壳结构的力学性能得到改善。压电纤维增强复合材料可用于结构的健康监测。可以将复合材料的传统优势与压电材料的特性相结合。.本项目提出一种多尺度方法用于建模和分析功能梯度纤维增强复合材料板壳结构的非线性弯曲、后屈曲和非线性动力响应。纤维增强和压电纤维增强复合材料的物性参数由细观力学模型估算。板壳结构的宏观控制方程基于高阶剪切变形理论。本项目的新贡献在于同时考虑材料的梯度属性和温度相关性。对功能梯度纤维增强复合材料板壳结构的重要问题做出探讨。给出不同几何和物理参数及不同载荷条件下数值结果。为先进复合材料在船舶和海洋工程中的应用提供必要的理论参考。

功能梯度材料是新一代的复合材料，其增强体在微观上呈非均匀分布。这种材料的显著特点是，在宏观尺度上各组份材料的体积含量在空间位置上是变化的。有两类功能梯度复合材料。一类是颗粒增强功能梯度复合材料。另一类是纤维增强功能梯度复合材料。将功能梯度材料的概念用于纤维增强复合材料层合结构，将增强纤维在基体中按一定的方式非均匀排布，从而使层合板壳结构的力学性能得到改善。压电纤维增强复合材料可用于结构的健康监测。可以将复合材料的传统优势与压电材料的特性相结合。.本项目的新贡献在于(1)提出一种多尺度方法用于建模和分析功能梯度复合材料梁板壳结构的非线性弯曲、后屈曲和非线性动力响应; (2)分析中同时考虑材料的梯度属性和温度相关性; (3)率先在国际上得到各类结构非线性问题的解。已发表学术论文30篇，“力学进展”评论文章1篇。研究成果可为先进复合材料在船舶和海洋工程中的应用提供必要的理论参考。