(1. 北京航空航天大学 航空科学与工程学院，北京 100191； 2. 沈阳飞机设计研究所，沈阳 110035)
摘 要: 通过理论、试验、数值模拟3种方法研究3D打印钛合金金字塔型点阵夹芯结构在两端简支三点弯曲载荷下的响应，试验中通过裂纹观测仪监测加载过程。结果表明：在弯曲载荷下，夹芯结构损伤区域主要在弯矩最大中线处附近；试件首先在上面板出现塑性变形，随着第一层杆件的屈曲，载荷迅速下降。通过扫描电子显微镜(SEM)观测断口形貌，验证面板及杆件均为弯曲变形失效。基于ABAQUS软件，建立结点刚硬点阵夹芯结构有限元模型，对结构的渐进损伤过程进行预测，获得损伤起始位置、损伤扩展、破坏载荷及最终破坏模式等结果，模拟结果与试验结果吻合较好。通过有限元模型分析宽度方向不同单胞列数的影响，结果表明列数越多，边界影响越小，结构承载能力越强。
关键字: 点阵夹芯结构；弯曲性能；渐进损伤；有限元模拟
（1. School of Aeronautic Sciences and Engineering, Beihang University, Beijing 100191, China; 2.Shenyang Institute of Aircraft Design, Shenyang 110035, China）
Abstract:Response of 3D printing pyramid lattice structure under three-point bending were studied. Progressive damage during the loading process was detected with crack observation instrument. The results reflect that the main damage zone is in the middle of the specimen, where the maximum bending moment is located. The sudden drop of the load occurs with the buckling of the truss. The scanning electron microscope(SEM) is used to observe the fracture morphology which proves that the panels and trusses failed by bending. Finite element model with rigid nodes were established using ABAQUS. Damage location, damage propagation, peak load and failure modes are obtained, which corresponds with the test results. The effects of different unit numbers in width were investigated. It indicates that with more unit cells in width, the effects of the boundary are weakened, resulting in improvement of the load bearing capacity.
Key words: truss core sandwich structure; bending property; progressive damage; finite element simulation
