考虑缺陷影响新能源飞机低成本复合材料柱壳结构非线性动力学分析

Considering the Impact of Defects on the Nonlinear Dynamic Analysis of Low-Cost Composite Cylindrical Shell Structures for New Energy Aircraft

摘要: 新能源飞机轻量化发展背景下，低成本制作的复合材料层合开口圆柱壳被广泛应用于机体关键承载结构，但其在实际服役过程中易产生各类预制缺陷与初始损伤，叠加高温复杂环境耦合作用，极易引发结构刚度退化、振动响应劣化等问题，严重威胁飞行器服役安全。现阶段关于复合材料壳体的研究多集中于完好结构振动分析，针对缺陷损伤、高温环境与载荷耦合作用下的非线性动力学机理研究仍存在不足，难以满足新能源飞机缺陷容限设计与振动控制的工程需求。本文以新能源飞机用低成本含缺陷复合材料层合开口圆柱壳为研究对象，综合采用理论建模、数值仿真与试验测试相结合的研究方法，开展多参数、多场耦合条件下含缺陷复合材料圆柱壳非线性动力学特性系统研究。取得成果如下：基于Love薄壳理论建立结构能量表达式，结合Rayleigh-Ritz法与拉格朗日方程推导振动控制方程，引入粘弹性缺陷本构与人工弹簧边界模型，构建含缺陷复合材料圆柱壳精细化非线性动力学理论模型；通过模态试验与有限元仿真对比，完成理论模型的有效性验证，分析缺陷尺寸、边界约束等因素对复合材料圆柱壳结构固有振动特性的影响规律。通过开展不同缺陷参数下结构振动试验，明确缺陷损伤诱发复合材料壳体动力学性能劣化的演化机制。在此基础上，建立热力耦合非线性动力学模型，探究高温与缺陷耦合作用下结构幅频响应、共振特征及非线性振动演变规律，揭示温度环境对含缺陷复合材料壳体振动行为的调控机理。研究结果阐明了约束条件、缺陷参数及高温环境对复合材料开口圆柱壳振动特性的影响机制，完善了含缺陷复合材料柱壳非线性动力学分析体系，可为新能源飞机复合材料结构缺陷容限优化设计、高温服役环境下振动抑制与安全防护提供理论参考与技术支撑。本文研究完善了低成本含缺陷复合材料层合开口圆柱壳的非线性动力学分析方法，揭示多因素耦合作用下结构振动特性的演化机制，有效弥补了现有研究模型理想化、因素单一化、材料针对性弱、机理研究浅薄等短板，可为新能源飞机复合材料壳体结构的缺陷容限设计、振动抑制优化、服役安全评估提供重要的理论支撑与技术参考。

Abstract: Against the background of lightweight development for new energy aircraft, low-cost fabricated composite laminated open cylindrical shells are widely applied to key load-bearing structures of airframes. However, various prefabricated defects and initial damages easily emerge during actual service. Coupled with the complex high-temperature environment, these imperfections inevitably lead to structural stiffness degradation, deterioration of vibration response and other adverse issues, which seriously threaten the service safety of aircraft. Current research on composite shells mainly focuses on the vibration analysis of intact structures, while investigations on the nonlinear dynamic mechanism under the coupling effect of defect damage, high-temperature environment and external loads remain insufficient. The existing research cannot meet the engineering requirements of defect tolerance design and vibration control for new energy aircraft. Taking low-cost defective composite laminated open cylindrical shells for new energy aircraft as the research object, this thesis adopts a combined method of theoretical modeling, numerical simulation and experimental testing to systematically investigate the nonlinear dynamic characteristics of defective composite cylindrical shells under multi-parameter and multi-field coupling conditions. The main research achievements are summarized as follows: Based on the Love thin shell theory, the structural energy expression is established. The vibration governing equations are derived by combining the Rayleigh-Ritz method and Lagrange equation. By introducing the viscoelastic defect constitutive model and artificial spring boundary model, a refined nonlinear dynamic theoretical model of defective composite cylindrical shells is constructed. The effectiveness of the theoretical model is verified through comparative analysis of modal tests and finite element simulations, and the influence laws of defect size, boundary constraints and other factors on the inherent vibration characteristics of composite cylindrical shells are analyzed. Structural vibration tests under different defect parameters are carried out to clarify the evolution mechanism of dynamic performance deterioration of composite shells induced by defect damage. On this basis, a thermo-mechanical coupling nonlinear dynamic model is established to explore the amplitude-frequency response, resonance characteristics and nonlinear vibration evolution law of structures under the coupled effect of high temperature and defects, and reveal the regulation mechanism of temperature on the vibration behavior of defective composite shells. The research results clarify the influence mechanism of constraint conditions, defect parameters and high-temperature environment on the vibration characteristics of composite open cylindrical shells, and improve the nonlinear dynamic analysis system for defective composite cylindrical shells. It can provide theoretical reference and technical support for the optimal design of defect tolerance, vibration suppression and safety protection of composite structures of new energy aircraft under high-temperature service environments. This study improves the nonlinear dynamic analysis method for low-cost defective composite laminated open cylindrical shells, and reveals the evolution mechanism of structural vibration characteristics under multi-factor coupling. It effectively compensates for the deficiencies of existing research, including idealized models, single research factors, weak material pertinence and superficial mechanism analysis. The research findings offer crucial theoretical support and technical reference for defect tolerance design, vibration suppression optimization and service safety assessment of composite shell structures of new energy aircraft.