低速冲击下复合材料层板压缩许用值

Compressive allowables of composite laminates subjected to low-velocity impact

  • 摘要: 为评估航空结构中常用的T300级和T800级2种碳纤维/环氧树脂复合材料层压板的冲击后压缩许用值,对2种材料体系下具有不同厚度及铺层的层板进行了低速冲击和冲击后压缩试验;讨论了冲击能量、凹坑深度、损伤面积及冲击后剩余压缩强度等之间的关系,以及厚度、铺层、表面防护等因素对其造成的影响;重点关注了2种材料体系下各组层板的目视勉强可见冲击损伤(BVID)形成条件以及含BVID层板的剩余强度.结果表明:厚度及铺层对层板的凹坑深度-冲击能量关系影响较大,而对冲击后压缩强度-凹坑深度及冲击后压缩破坏应变-凹坑深度关系影响较小,且在相同铺层比例下,BVID对应的冲击能量随厚度近似呈线性增长.X850层板的损伤阻抗性能明显优于CCF300/5228层板的,但二者损伤容限性能相当.加铜网、涂漆等表面处理显著提高了层板的损伤阻抗,但对损伤容限性能影响不大;在损伤不超过BVID时,所有CCF300/5228试件的压缩破坏应变均大于4 000 με,而X850材料体系下压缩破坏应变均在3 000 με之上.

     

    Abstract: In order to evaluate the compressive allowables of composite laminates made from two types of carbon fiber/epoxy composite laminates with the fiber of T300 and T800, which are commonly used in aeronautical structures, low-velocity impact and compressive after impact tests were carried out for composite laminates made from the two composite systems with different thicknesses and stacking sequences. The relationships between impact energy, dent depth, damage area and residual compression strength etc were discussed, and the effects of thickness, stacking sequence, surface protection etc were also investigated. The condition for the barely visible impact damage (BVID) formation and the residual strengths of the composite laminates containing BVID were specially concerned. The results show that the laminate thickness and stacking sequence can affect the dent depth-impact energy relationship greatly, while their influences on the compressive strength after impact-dent depth and compressive failure after impact strain-dent depth relationships are much smaller. In the condition of the same layup proportion, impact energy for the BVID formation increases linearly with the laminate thickness. The performances of laminates with different materials vary that the X850 laminates have a better impact damage resistance than the CCF300/5228 laminates, but their damage tolerance performances are similar. Surface treatment such as adding the bronze and painting, can enhance the impact damage resistance of the laminates greatly, while it has little influence on the damage tolerance performances. The compressive failure strain of all the CCF300/5228 samples are more than 4 000 με, while they are more than 3 000 με for X850 samples, when the damage is not more than BVID.

     

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