竹杨层积复合材料的冲击性能

以结构用竹杨层积复合材料为研究对象,采用落锤式冲击实验方法,研究垂直和平行层积方式两种冲击方向下的竹杨层积复合材料的冲击性能。结果表明:两种冲击方式下竹杨层积复合材料的冲击韧性、冲击过程和破坏方式均不相同。沿垂直方向冲击持续时间(17.21 ms)大于平行方向(11.37 ms),且垂直方向冲击过程吸收的总能量(524.42 J)也大于平行方向(403.56 J),冲击韧性垂直方向(24.16 J/cm²)优于平行方向(18.64 J/cm²)。由于垂直方向冲击过程中主要由纵向和横向应力波作用,裂纹扩展过程较长,破坏方式主要是弯曲破坏和层间胶层剪切破坏; 而平行方向冲击破坏以纵向应力波作用为主,主要发生弯曲剪切破坏。单元结构和胶合界面是影响竹杨层积复合材料冲击韧性的主要原因。

Impact performance of bamboo/poplar laminated composite

In order to enrich the mechanical base data of bamboo/poplar laminated composites(BPLC)and broaden its application, the impact performance of the BPLC in perpendicular(R direction)and parallel(T direction)to the laminated direction were examined using the falling weight impact method. Results indicated that the impact toughness, impact process and fracture modes of BPLC were different in these two directions. When BPLC was impacted in the R direction, the impact time was longer than that in the T direction(17.21ms and 11.37ms), absorbing more energy(R direction 524.42 J, T direction 403.56 J)and representing higher impact toughness(R direction 24.16 J/cm², T direction 18.64 J/cm²). In the R direction, the composite was impacted by the perpendicular and parallel stress waves. The crack propagation process extended, leading to bending and shearing fracture which consumed more energy. Thus, the impact toughness in the R direction was better than that in the T direction. However, in the T direction, the main stress wave was in perpendicular direction, corresponding to perpendicular shear fracture. Most failures occurred in the portions of bamboo and the interface between bamboo and poplar, which determined the impact toughness of BPLC.