多态碳纤维复合材料的垂直剪切断裂行为

Vertical Shearing Fracture Behavior of Carbon Fiber Reinforced Plastic of Different Status

针对由环氧树脂膜及增强碳纤维织物交替铺放构成的碳纤维复合材料(CFRP)随温度变化所呈现的干态(室温固态)、软态(玻璃态转化温度区间)、湿态(树脂融熔温度区间)及固态(开始固化温度)特征,使用自主设计的剪切冲裁模具进行系列冲裁实验,分析了多态CFRP材料在不同工艺条件下的垂直剪切断裂行为和特征,并解释了相应的影响机理。结果表明:相对于干态碳纤维织物,干态/固态、软态、湿态CFRP材料在垂直剪切断裂过程中呈现出典型的非线性变形、非连续、分层断裂特性,但是剪切断裂所需的最大载荷依次增大;另外,较小的冲裁间隙和剪切角度、较高的冲裁速度有利于减弱局部纤维束的非连续断裂,使分层断裂更为集中和稳定。

Carbon fiber reinforced plastic（CFRP） was fabricated by alternately laying epoxy resin films and carbon fiber fabrics for a desired number of layers. The prepared CFRP could be in different status such as dry, soft, wet and solid corresponding to ambient temperature, and temperatures of glass transition and melting and curing of resin films, respectively. Blanking tests were performed by means of a home made shearing blanking die to characterize the vertical shearing fracture for the prepared CFRP of different status. Results show that the vertical shearing fracture of the dry/solid, soft and wet CFRPs present characteristics of typical nonlinear deformation, discontinuous and delaminating fracture, and the required blanking forces increase in turn. Moreover, blanking with a small gap, proper angle and high speed may be helpful to relieve the discontinuous fracture of partial carbon fiber yarns and promote the delaminating fracture of CFRPs to be much concentrated and stability.