含预制缺陷PLA蜂窝加筋结构承载力分析

Analysis of Bearing Capacity of PLA Honeycomb Reinforced Structure with Prefabricated Defects

目的 分析不同加筋构型及预制缺陷形式对蜂窝加筋结构抗弯承载能力的影响。方法 以热塑性PLA为基材,通过增材制造技术,制备含预制缺陷蜂窝加筋结构试件,考虑缺陷的长度、数量、深度、方向等因素,采用三点弯曲实验方式,并结合有限元仿真结果进行综合分析。结果 实验得到了结构的位移-荷载关系及破坏情况。线弹性变形阶段,实验与仿真拟合良好,该阶段内,六边构型PLA蜂窝加筋曲板结构承载能力整体优于正六边结构,但后者在后屈曲阶段的残余承载能力更好,且更不易发生断裂。相较于缺陷长度,缺陷深度和缺损肋壁数量对结构承载力的影响更为显著。缺陷方向越趋近宽度方向,结构承载能力越低。结论 实际工程中,应尽可能避免结构中间承载位置处横向加筋肋壁出现缺损,并充分利用正六边与内六边构型蜂窝加筋结构各自的承载优点。

The work aims to analyze the effect of different reinforcement configurations and prefabricated defect forms on the flexural bearing capacity of honeycomb reinforced structures.With thermoplastic PLA as the base material,the honeycomb stiffened structure specimens with prefabricated defects were prepared by additive manufacturing technology.Considering the length,quantity,depth and direction of the defects,the three-point bending test method and the finite element simulation results were used for comprehensive analysis.The displacement-load relationship and failure of the structure were obtained.The experiment and simulation fitted well in the linear elastic deformation stage.In this stage,the bearing capacity of the hexagonal configuration PLA honeycomb reinforced curved plate structure was better than that of the regular hexagonal structure,but the latter had better residual bearing capacity in the post-buckling stage and was less prone to fracture.Compared with the defect length,the defect depth and the number of defective rib walls had a more significant effect on the bearing capacity of the structure.The closer the defect direction was to the width direction,the lower the bearing capacity of the structure was.In practical engineering,the defect of transverse reinforced rib wall at the middle bearing position of the structure should be avoided as much as possible,and the respective bearing advantages of regular hexagon and inner hexagon honeycomb reinforced structures should be fully utilized.