A Model for Shear Stress Relaxation Around a Fiber Break in Unidirectional Composites and Creep Rupture Analysis
A Model for Shear Stress Relaxation Around a Fiber Break in Unidirectional Composites and Creep Rupture Analysis
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单向复合材料中纤维断裂周围剪切应力松弛模型和蠕变断裂分析
DOI：
10.1007/0-306-46937-5_13
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
M. Mizuno
中科院分区：
文献类型：
--
作者：
N. Ohno;H. Kawabe;T. Miyake;M. Mizuno
本文建立了长脆性纤维增强单向金属基复合材料断裂纤维中的应力松弛模型。采用了一种将断裂纤维嵌入幂律蠕变矩阵的圆柱形单元，并假定断裂纤维具有双线性轴向应力分布。在此基础上，以胞内能量平衡为基础，导出了作用于应力恢复段的界面剪应力松弛方程。在总应变恒定的情况下，对松弛方程进行合理近似和积分得到解析解，与Du和McMeeking（1995）的数值分析结果相当吻合。此外，将松弛方程与Curtin（1991）模型相结合，在全局荷载分担的假设下，对长期蠕变的破裂时间进行了解析、明确的评价。结果表明，所得关系较好地反映了单向金属基复合材料蠕变破裂时间随外加应力的变化规律。
This paper describes a model of stress relaxation in broken fibers in unidirectional metal matrix composites reinforced with long brittle fibers. A cylindrical cell with a broken fiber embedded in a power law creeping matrix is employed, and the broken fiber is assumed to have a bilinear distribution of axial stress. Then, on the basis of energy balance in the cell, a relaxation equation of interfacial shear stress acting on stress recovery segments is derived in a simple form. Under constant overall strain the relaxation equation is approximated rationally and integrated to obtain an analytical solution, which is shown to agree fairly well with the numerical analysis of Du and McMeeking (1995). Moreover, the relaxation equation is combined with Curtin’s (1991) model, so that rupture lime in long term creep is evaluated analytically and explicitly on the assumption of global load sharing. It is shown that the resulting relation represents well the dependence of creep rupture time on applied stress observed experimentally on a unidirectional metal matrix composite.