Octet-truss点阵结构的断裂行为研究及结构增韧设计  

Fracture behavior study of the Octet-truss lattice structures and structural toughening design

作　　者：何婉青 王宇航 罗伟洪 王志勇[1,2] HE Wanqing;WANG Yuhang;LUO Weihong;WANG Zhiyong(Institute of Applied Mechanics,College of Aeronautics and Astronautics,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Key Laboratory of Material Strength&Structural Impact,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学航空航天学院应用力学研究所,太原030024 [2]太原理工大学材料强度与结构冲击山西省重点实验室,太原030024

出　　处：《机械强度》2025年第2期130-137,共8页Journal of Mechanical Strength

基　　金：国家自然科学基金面上项目(12272257);山西省基础研究计划项目(202203021211169)。

摘　　要：Octet-truss点阵结构具有高强、高韧以及轻质化的特征,是工程领域的优选材料之一。对具有浅预制裂纹的Ti6Al4V Octet-truss点阵结构进行了三点弯曲试验,并结合数字图像相关(Digital Image Correlation,DIC)技术对断裂过程进行观测。为了深入研究点阵结构的断裂韧性,针对结构的三点弯曲断裂行为进行有限元分析,利用各向同性弹塑性力学模型表征结构杆件组元的力学响应,试验验证了模型的有效性。基于结构的弹塑性断裂行为,利用J积分法计算Octettruss点阵结构的断裂韧性。结果表明,Octet-truss点阵结构的断裂韧性与其相对密度、杆件长度的平方根呈正相关。对于裂纹尖端处的杆件组元,不同平面的杆件在相同截面尺寸下具有不同的应力状态和变形模式。针对结构的失效模式,通过优化不同平面杆件之间的截面尺寸比例平衡各杆件的应力状态,实现相同相对密度下的结构增韧。Octet-truss lattice structure is one of the preferred materials in engineering field with light,high strength and high toughness properties.Three-point bending experiments were carried out on Ti6Al4V Octet-truss lattice structure with shallow pre-crack,and the fracture process was observed by digital image correlation(DIC)technique.To further study the fracture toughness of Octet-truss lattice structure,the fracture behavior of the structure under three-point bending load was analyzed by finite element method.The mechanical response of the truss member for the structure was characterized by the isotropic elastoplastic mechanical model.The validity of the finite element model was verified by experiments.Based on the elastic-plastic fracture behavior of the structure,the J-integral method was used to calculate the fracture toughness of the Octet-truss lattice structures.The results show that the fracture toughness of the Octet-truss lattice structure increases linearly with the relative density and the square root of the truss length.For the truss member at the crack tip,truss in different planes have different stress states and deformation modes with the same cross-sectional size.According to the failure mode of the structure,the stress state of truss from different planes is balanced by optimizing the proportion of the cross-section size,which can optimize toughness of the lattice structure with same relative density.

关 键 词：Octet-truss点阵结构 数字图像相关 J积分 数值模拟 结构增韧设计 

分 类 号：O346.1[理学—固体力学]