多仿生中空曲边点阵结构压缩力学及吸能特性

Compression mechanics and energy absorption characteristics of multi-bionic hollow curved lattice structure

  • 摘要: 为开发出具有增强力学性能和卓越能量吸收能力的轻质结构,提出了一种具备高平台应力、高刚度、高强度、高比吸能等特性的新型多仿生中空曲边(Multi-bionic hollow curve,MHC)点阵结构。利用Ls-Dyna软件建立了体心立方(Body centered cubic,BCC)点阵结构在准静态压缩下的有限元数值模型,并通过试验与数值模拟结果的对比验证了模型的准确性。此外,对BCC、曲边体心立方(Curve body centered cubic,CBCC)、中空体心立方(Hollow body centered cubic,HBCC)以及MHC点阵结构开展准静态单轴压缩下的力学及吸能特性研究。研究结果表明:MHC点阵结构通过将中空与曲边的结合设计,显著提高了该结构的截面惯性矩,并呈现出支杆弯曲与薄壁压溃两种变形模式,增加了压缩过程中的塑性铰的数量,使其获得更强的力学性能。通过研究结构参数对MHC点阵结构力学及吸能特性的影响,发现当振幅为0.8 mm、壁厚为0.5 mm、外径为7.2 mm时的MHC点阵结构相较于BCC点阵结构在平台应力、比吸能、比强度以及比刚度方面分别提升了176.3%、231.3%、424.0%和716.8%。该多仿生特征集成方法为轻质高性能点阵结构的设计提供了创新策略,具有重要的应用前景。

     

    Abstract: To develop lightweight structures with enhanced mechanical properties and excellent energy absorption capabilities, the new multi-bionic hollow curve (MHC) lattice structure has been proposed. The MHC structure exhibits high plateau stress, stiffness, strength, and specific energy absorption. Finite element models of the body centered cubic (BCC) lattice structures under quasi-static compression were established using Ls-Dyna software. The accuracy of the numerical model was validated by comparing the experimental and simulation results. Additionally, the mechanical and energy absorption properties of BCC, curve body centered cubic (CBCC), hollow body centered cubic (HBCC), and MHC lattice structures under quasi-static uniaxial compression were studied. The results show that the MHC lattice structure, by combining hollow and curved designs, significantly enhances the moment of inertia of the structure's cross-section and exhibits two deformation modes: strut bending and thin-walled crushing. This design increases the number of plastic hinges during compression, resulting in superior mechanical performance. Parametric studies show that when the amplitude is 0.8 mm, the wall thickness is 0.5 mm, and the outer diameter is 7.2 mm, the MHC lattice structure exhibits 176.3%, 231.3%, 424.0%, and 716.8% improvements in plateau stress, specific energy absorption, specific strength, and specific stiffness, respectively, compared to the BCC lattice structure. The integration of multiple biomimetic features offers an innovative strategy for designing lightweight, high-performance lattice structures with significant application potential.

     

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