摘要
三维编织复合材料被大量用于航空结构设计,在航空服役过程中需承受各种复杂载荷。测量三维编织复合材料内部原位应变,将其应用于建立材料失效预警系统和结构强度设计。在三维编织复合材料内部埋植光纤Bragg光栅传感器和在材料表面粘贴应变片,同时测量结构内部和表面原位应变。构建均质模型和细观结构模型,采用有限元方法分析内部原位应变场分布,有限元分析结果和试验测量结果吻合性较好。发现在准静态单轴拉伸载荷作用下,三维编织复合材料不同位置原位应变值产生变化。三维编织复合材料轴向正中间截面应变分布较为均匀;内单胞处原位应变略大于面单胞处原位应变(最大差值约0.08%);外表面原位应变大于面单胞处原位应变(最大差值约0.1%)。在三维编织复合材料航空结构设计中,需要充分考虑并合理使用三维编织复合材料不同位置的应变值,使材料设计和利用效率最大化。
Three-dimensional(3D) braided composites have been widely applied to aero-structure design. They are subjected to various complex loadings during aerospace engineering service. If the in-situ strains in 3D braided composites have been measured precisely, the early-warning failure system and strength optimization could be achieved. The fiber Bragg grating(FBG) sensors in 3D braided composites were embedded, and strain gauges at the surfaces were glued. Insitu strains of the interior and outer surfaces of the 3D braided composites were simultaneously measured. Homogeneous model and micro-structural model have been established for finite element analysis(FEA). The internal in-situ strain distributions have been compared between FEA and the tests. The FEA results were in good agreement with the tests. Under quasi-static uniaxial tensile loading, the strain varies with the different locations. The strain distribution is uniform at the middle cross-section of 3D braided composites. The strain of the interior unit-cell is slightly larger than the strain of the surface unit-cell(the maximum difference is about 0.08%). The strain of the outer surface is slightly larger than the strain of the surface unit-cell(the maximum difference is about 0.1%). It is inferred that the different strains at the different locations in the 3-D braided composites should be considered fully to optimize the efficiency of the material design.
作者
严烁
孙宝忠
顾伯洪
YAN Shuo;SUN Baozhong;GU Bohong(College of Textiles,Donghua University,Shanghai 201620,China)
出处
《航空制造技术》
2020年第15期70-80,共11页
Aeronautical Manufacturing Technology
基金
国家自然科学基金(51875099、51675095)。
