复合材料裂纹敏感性的评定──(Ⅱ)HTA/6376和T300/M10的Ⅱ型分层扩展行为

应用ENF试验研究了HTA/6376和T300/M10两种碳/环氧复合材料的静态与疲劳层间断裂行为。在静态载荷下,两种材料均呈现脆性不稳定和稳定的裂纹扩展特性。在R=0.1且△G_I大幅度变化的疲劳加载过程中,两种材料呈现稳定的裂纹扩展。采用位移控制方法,确定了裂纹扩展速率与循环应变能释放率的关系和应变能释放率门槛值。与T300/914C相比,HTA/6376和T300/M10具有较高的抗裂纹扩展能力。

ASSESSMENT OF CRACK SENSITIVITY IN COMPOSITES──(Ⅱ)MODE II DELAMINATION GROWTH BEHAVIOR OF HTA/6376 AND T300/M10

The end notched flexure (ENF) test was employed in an investigation of interlaminar fracture behavior in Mode II static and, fatigue loading for carbon/epoxy composites T300/M10 and HTA/6376. Under static loading,both of the materials exhibited bittle unstable and brittle stable behavior of crack growth. Stable Mode II crack growth was observed during fatigue loading with R=0.1 in a larger range of cyclic strain energy release rate. A consistent relation of crack growth rate to the cyclic strain energy release rate was obtained for the composites. Within the range of moderate crack growth rate,the data of Mode II fatigue crack growth obeyed a power law. The trend of reduction in crack growth rate data with degredation in cyclic strain energy release rate suggests the presence of a threshold strain energy release rate. Compared with T300/914C,HTA/6376 and T300/M10 have higher crack growth resistance.