基于多材料耦合梁方法大型复合材料-金属混合船舶极限强度研究

Composite-metal hybrid ship is composed of fiber reinforced composite superstructure and metal main hull. This ship can integrate the strength and stiffness advantages of the metal main hull and the light and multi-functional characteristics of the composite superstructure, and meet the needs of stealth and lightweight for large-scale military and civilian ships. Due to the particularity of anisotropic composites and the diversity of structural response with different materials, the mechanical behavior of hybrid ships is more complicated than conventional ships. The traditional methods have shortcomings in solving the problems of the coupling mechanism, failure modes and ultimate strength for ship structures with multi-material. The industry urgently need to break through the relevant theoretical and technical bottlenecks. The subject explores the mechanical response law between internal structures of the hybrid ship, models the coupled beam system, extends the applicable range of the traditional coupled beam theory from a single material to multiple materials, and proposes a multi-material coupled beam method for hybrid ships. A progressive failure nonlinear numerical method is established to analysis the macro/microscopic mechanical behavior and failure characteristic of the hybrid ship structure. And the deficiency of beam theory to deal with micromechanics is compensated. Based on theoretical exploration, numerical analysis and experimental verification, a semi-theoretical and semi-numerical method of ultimate strength prediction for hybrid ships is put forward. The mechanical coupling mechanism between large-scale composite superstructure and metal main hull, the ultimate strength response law of the hybrid ship, and the efficiency of composite superstructure is revealed. The research provides a theoretical reference for the design, application and safety assessment of the new large and lightweight passenger ships and cruises.

复合材料-金属混合船舶由纤维增强复合材料上层建筑和金属主船体构成，集成金属船体强度、刚度优势及复合材料上建比重小、多功能的特性，能有效满足大型军、民船隐身、轻量化的发展需求。因各向异性复合材料特殊性和不同材料结构响应多样性，混合船力学行为比常规船更加复杂，传统方法解决多材料结构耦合机理、失效模式和极限强度问题时存在局限，急需突破相关理论技术瓶颈。课题探究混合船体结构力学响应规律，构建耦合梁系模型，将传统耦合梁理论适用范围从单一材料拓展至多材料，提出多材料耦合梁方法；构建渐进失效非线性数值方法，研究混合船体结构宏/细观力学行为表征和失效特性，弥补梁理论处理细观力学问题的不足；综合理论探索、数值分析和实验验证，提出半理论-半数值混合船舶极限强度预测方法，揭示大型复合材料上建与金属船体间力学耦合关系、极限强度响应规律及复合材料上建效率，为新一代大型轻量化客船、邮轮设计应用、安全评估提供理论基础。

复合材料-金属混合船舶能够有效满足大型军、民用船舶隐身、轻量化等发展需求，在船舶领域的应用日益增多。复合材料上层建筑与金属主船体之间的相互关系非常复杂，混合船体结构的极限强度问题是造船界长期关注的问题之一。本项目研究了复合材料-金属混合船舶结构的离散方法，建立了梁单元间的多向耦合关系，构建了混合船舶耦合梁系模型，提出并验证了耦合梁方法。该方法明确了耦合梁结构的控制方程以及上建与主船体之间转换层的力学作用，能快速预报船体梁的弯矩-曲率关系、纵向剪切耦合关系以及任意跨耦合刚度与极限剪切位移间的关系，有效表征大型上建与主船体的相互作用。针对混合船体结构的非线性分析问题，重点研究了复合材料的本构关系、失效准则和退化方案，形成了兼顾宏、细观分析的非线性数值计算方法和渐进失效数值分析流程，完成了复合材料板架梁等多种船舶典型结构的力学行为分析，证明该方法可有效预报船体结构的极限强度、失效模式以及力学响应规律等。针对多材料混合船体结构，提出了半理论-半数值极限强度预测分析方法，基于该方法从弯矩分配系数角度研究了不同形式上建对混合船舶总纵弯曲强度的贡献率，并剖析了几何尺度、材料特性等参数对混合船舶力学行为的响应规律。搭建了多尺度力学试验系统并完成了不同形式板架梁和多材料混合船体梁的强度试验，验证了耦合梁方法和极限强度预测分析方法。项目研究成果可以有效表征大型上建与主船体间的耦合作用关系，明确上建、主船体的弯矩分配情况，并评估不同形式、不同材料船体结构在多种工况下的力学特性及响应规律，能够为新一代大型轻量化客船、豪华邮轮等大尺度船舶的设计优化、结构安全评估等提供参考依据。