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中文核心期刊

基于曲率连续性的ANCF柔索动网格自适应计算

DYNAMIC MESH ADAPTIVE COMPUTATION FOR ANCF-BASED FLEXIBLE CABLES VIA CURVATURE CONTINUITY

  • 摘要: 柔索作为典型大变形柔性结构, 广泛应用于航空航天、海洋工程等领域, 其动力学仿真精度与效率高度依赖网格划分策略. 传统固定网格方法进行柔索动力学分析时, 常因大变形区域单元不足、小变形区域过度离散, 导致精度与效率失衡, 难以满足工程需求. 为解决此难题, 本研究基于绝对节点坐标法(ANCF)建立柔索单元模型, 从柔索平衡方程推导单元残差表达式, 通过理论与数值验证, 揭示节点曲率跳变量与残差的内在关联. 据此突破传统方法局限, 创新性提出以曲率连续性作为自适应网格划分的核心判别指标, 有效规避了自适应有限元中主流的残差估计法在复杂系统中平衡方程构造繁琐、额外计算开销大的缺陷. 进而构建通过节点动态增删实现单元分裂与合并的自适应网格更新策略, 实现网格资源的精准分配. 仿真表明, 所提方法在保障能量连续性的同时, 可精准捕捉柔索位形变化, 大变形区域单元自动加密以保障精度, 小变形区域单元精简以提升效率, 通过调整自适应阈值参数, 可灵活调控精度与效率, 实现二者最优平衡. 本研究为大变形柔性结构动力学分析提供了兼具精度与效率的计算方案, 可扩展至复杂多柔体系统, 为航空航天、海洋工程缆绳及机械臂绳驱机构的设计优化与工程应用提供理论支撑.

     

    Abstract: As a typical large-deformation flexible structure, flexible cables are widely used in aerospace, marine engineering and other fields. The accuracy and efficiency of their dynamic simulation are highly dependent on mesh generation strategies. Traditional fixed mesh methods often suffer from a trade-off between accuracy and efficiency due to insufficient discretization in large-deformation regions and excessive discretization in small-deformation regions, which makes it difficult to meet engineering requirements. To address this challenge, this study establishes a flexible cable element model based on the Absolute Nodal Coordinate Formulation (ANCF). From the equilibrium equation of the flexible cable, the element residual expression is derived. Through theoretical and numerical verification, the intrinsic correlation between the nodal curvature jump value and the residual is revealed. Based on this finding, this study overcomes the limitations of traditional methods and innovatively proposes curvature continuity as the core discriminant index for adaptive mesh generation. This approach effectively avoids the drawbacks of cumbersome equilibrium equation construction and large additional computational cost of mainstream residual estimation methods in adaptive finite elements for complex systems. Furthermore, an adaptive mesh update strategy that realizes element splitting and merging through dynamic node addition and deletion is constructed to achieve precise allocation of mesh resources. Simulation results show that the proposed method can accurately capture the configuration changes of flexible cables while ensuring energy continuity: elements in large-deformation regions are automatically refined to guarantee accuracy, whereas elements in small-deformation regions are simplified to improve efficiency. By adjusting adaptive threshold parameters, the accuracy and efficiency can be flexibly regulated to achieve their optimal balance. This study provides a computation scheme with both accuracy and efficiency for the dynamic analysis of large-deformation flexible structures, which can be extended to complex multibody systems. It also offers theoretical support for the design optimization and engineering application of cables in aerospace, marine engineering, and rope-driven mechanisms of manipulators.

     

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