自动铺放内嵌缺陷构件成型方式对拉伸性能的影响

自动铺丝技术使单向的复合材料丝束铺放轨迹得以优化,但是在应用此技术铺放复杂形状结构时可能会导致缺陷的引入。为解决此问题,利用2丝束自动铺放机器人铺放含有空隙和重叠缺陷的层合板试件,按照(90°/0°)5/90°]和(0°/90°)5/0°]的顺序,将缺陷分别置于0°和90°铺层内。在试件成型过程中,无模压板的成型方法会导致试件局部厚度和微观结构的变化,这主要取决于缺陷的类型,这对试件的拉伸性能有很大影响,使用模压板可以很好地改善这一点。试验表明:在0°纤维方向上,含空隙缺陷加模压板成型的试件较不加模压板成型的试件拉伸强度提升了218. 5%,重叠缺陷试件加模压板成型后试件拉伸强度也提高了69%;在90°纤维方向上,由于90°方向铺层不是主承载层,模压板对试件性能影响较小,但加模压板成型后,空隙和重叠缺陷试件的拉伸性能也分别提高了3. 2%和15. 6%。

Influence of Forming Method of Embedded Defects Introduced by Automated Fiber Placement on Tensile Properties

Automated fibre placement (AFP) enables the trajectory of unidirectional composite tape to be optimized,but laying down complex shapes with this technology can result in the introduction of defects.In order to solve this problem,the specimens are manufactured by an automated fiber machine which enables 2 prepreg fiber tows to be draped simultaneously,gap and overlap embedded defects are introduced on two cross-ply layups of (90°/0°)5/90°] and (0°/90°)5/0°].Autoclave cure without a caul plate results in local thickness variation and microstructural changes which depend on the defect type.This has a strong influence on mechanical performance. Use of a caul plate improves these variations.In the case of gap defects with fiber angle 0°,the tensile strength of the plate with a caul plate increased by 218.5%. In the case of overlap defects with fiber angle 0°,the tensile property of the plate with a caul plate is 69% higher than the plate without it. The direction of 90°fiber is not the main bearing layer,the caul plate is less effective in the defects with it.But the tensile property of the gap and overlap specimens with a caul plate is improved by 3.2% and 15.6% respectively.