考虑含界面裂纹应力集中系数的复合材料强度计算

弱界面复合材料受横向拉伸时,界面会在材料整体破坏前发生脱粘,材料横向拉伸强度甚至远低于纯基体的拉伸强度。为了准确地预测弱界面复合材料的偏轴强度,需要考虑和量化纤维埋入及界面脱粘对基体现场强度的影响。定义考虑界面裂纹的应力集中系数,提出一种新的方法用于预测弱界面复合材料在任意角度偏轴拉伸作用下界面脱粘对应的临界外加载荷和材料的整体强度;并对不同种类的复合材料进行算例分析。结果表明:加入新定义的应力集中系数可以明显提高预测的准确性。

The stress concentration factor of composite materials with interfacial cracks

When the weak interface of composite materials subjected to the transverse tensile, composites with weak interface involve interfacial cracks before the overall damage of the material. The measured transverse tensile strength of the weak interfacial bonding composite is even much smaller than the original tensile strength of the pure matrix. The stress concentration factor (SCF) is defined considering the existence of cracks on interfaces with in-situ strength of the matrix assigned as its original counterpart divided by the SCF. A new method is provided to predict the load level when the interface crack occurs and the strengths of composites under uniaxial tensile.