低速撞击下正交型纤维增强复合材料层板的脱层研究

A Study on the Delamination of Glass/Epoxy Laminates under Low Velocity Impact

用不饱和聚脂预浸渍玻璃纤维带制作了几种正交型铺层序列的层板梁试件,并对其在固支条件下进行了横向冲击实验。用嵌入式加速度传感器得到了载荷历史,通过高速摄影机和显微摄像系统从层板侧面观察了脱层现象。根据最大剪应力准则,通过对层板内部剪应力的分布以及不同铺层间三种不同剪切破坏强度的近似分析,解释了首次脱层具体位置和二次脱层现象。试验和分析表明,脱层失稳所对应的脱层阈值载荷与试件的铺层结构有关。但是,对不同铺层结构的试件,发生脱层的0°/90°界面具有相同的细观剪切强度。因此,用细观界面剪切强度来分析和预言试件的脱层失稳更具有一般性。

Orthogonal laminate beam specimens were prepared by using unsaturated polyester preimpregnated glass-fiber tapes. Transverse impact tests were conducted on clamped laminate beams with different layout. An accelerometer was embedded in the hammer to obtain force history. Delamination was observed by using a high-speed digital camera and a micro CCD camera. The shear stress distributions in the beams and the shear strengths at three different interfaces were discussed. Based on the critical shear stress principle, an approximate analysis was presented to explain the locations of delamination and secondary delamination. The results show that the delamination threshold load depends on the layout of the laminate, and the critical microscopic shear stress at the 0°/90° interface is nearly the same. Therefore the microscopic shear strength can be used to predict the delamination instability.