热-力耦合作用下纤维金属层合结构的非线性静动力学性能及其破坏机理研究

In this project, the fiber-metal laminated plates and shells in the steady and unsteady temperature field under the coupled thermo-mechanical loads are mainly investigated as the research subject. Considering the factors of multi-phases and physical nonlinearity for materials, geometric nonlinearity for the structures, in-plane damages, interfacial damages and their evolution, the thermo-elastic constitutive relationship, thermo-elasto-plastic damage constitutive relationship, elasto-plastic contact law of the impact, the damage accumulation law of the in-plane and interfacial damage with various damage states are examined, and the nonlinear static and dynamic governing equation for reflecting the progressive failure of fiber-metal laminated structures objectively, heat conduction equation and damage evolution equation are established. Then the semi-analytical method for this complicated nonlinear system is sought. On the basis of above works, the influences of thermal effect, damage effect and other factors on the nonlinear mechanical behavior of the fiber-metal laminated structures are discussed extensively, and the failure mechanism of these structures in the case of elastic damage, elasto-plastic damage, fatigue damage and impact damage under the coupled thermo-mechanical loads are revealed synthetically. Afterward, the accuracy of the above theoretical analysis will be validated by the corresponding experiment. It is hoped that the achievements obtained in this project enrich and develop the continuum damage mechanics,composite mechanics, nonlinear mechanics and thermo-elastic theory. Furthermore, it will provide the theoretical basis for the optimized design, lifetime prediction and the reliability evaluation of the fiber-metal laminated structures. This project is meaningful and valuable in the related theoretical study and engineering application.

本项目以热-力耦合作用下处于非定常温度场或定常温度场中的纤维金属层合板壳结构为研究对象，综合考虑材料的多相与物理非线性、结构几何非线性、层内与界面损伤及其演化等因素，探讨其热弹性和热弹塑性损伤本构关系、弹塑性冲击接触模型、不同损伤状况下层内与层间界面损伤的累积规律；建立较客观地反映纤维金属层合结构渐进破坏过程的非线性静、动力学控制方程、热传导方程和损伤演化方程，寻求此类复杂非线性系统的半解析求解方法；讨论热效应、损伤效应等因素对该类结构非线性力学性能的影响，揭示在不同热-力荷载耦合作用下该类结构分别处于弹性损伤、弹塑性损伤、疲劳损伤等状况时的破坏机理，并通过实验对理论分析结果予以验证。本项目的工作将丰富和发展连续介质损伤力学、复合材料力学、结构非线性力学和热弹性理论，同时可为该类结构的优化设计、寿命预测，可靠性评定提供理论依据，具较大的理论意义和工程应用价值。

本项目以热-力耦合作用下处于定常温度场或非定常温度场中的纤维金属层合板壳结构为研究对象，基于连续介质损伤力学、弹塑性理论、热力学定律、压电理论和结构非线性动力学，探索了纤维金属层合材料的塑性屈服准则、硬化规律和弹塑性模型；建立了具损伤的弹塑性本构模型和相应的损伤演化方程；综合考虑损伤效应、热效应、压电效应、横向剪切变形、结构几何非线性和材料物理非线性等因素，建立了纤维金属层合结构的非线性静动力学控制方程和非线性热冲击动力学模型；提出了求解此类复杂非线性静动力学系统的有效计算方法。在以上工作基础上，系统地研究了纤维金属层合结构的热屈曲、热后屈曲、自由振动、非线性动力响应、振动主动控制、脱层扩展和移动荷载作用下的非线性动力响应等问题；讨论了损伤效应、热效应、压电效应、材料物理非线性、结构几何参数等因素对纤维金属层合结构非线性静动力行为的影响，揭示了纤维金属层合板壳结构的若干非线性静动力学本质特征和失效机理，并通过实验对理论分析进行了验证。本项目的研究成果丰富和发展了结构非线性静动力学、连续介质损伤力学和弹塑性理论，达到了预期的研究目标。