NOTCH-SENSITIVITY AND SHEAR BANDS IN BRITTLE-MATRIX COMPOSITES
NOTCH-SENSITIVITY AND SHEAR BANDS IN BRITTLE-MATRIX COMPOSITES
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DOI：
10.1016/0956-7151(94)90403-0
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发表时间：
1994-09-01
期刊：
影响因子：
--
通讯作者：
SUO, Z
中科院分区：
文献类型：
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作者：
HE, MY;WU, B;SUO, Z
基体开裂、纤维断裂和界面滑动会导致纤维增强脆性基体复合材料发生非线性变形。当有缺口的样品受到拉伸载荷时，非线性变形通常集中在缺口周围，使韧带中的应力分布更均匀，从而导致更高的断裂载荷。我们模拟两种变形机制的相互作用：切口前面的拉伸带和垂直于切口的剪切带。剪切变形使拉伸带中的应力分布变得均匀，拉伸带的强度决定了剪切变形的程度。每个带都通过牵引变形定律进行模拟。断裂功是根据小规模非弹性问题计算的，缺口样品的断裂载荷是根据大规模非弹性问题计算的。模拟得出了几个重要的结论。首先，弱剪切带会大大增加断裂功。其次，通过独立于剪切带描述的公式，缺口样品的断裂载荷与无缺口强度、断裂功和缺口尺寸密切相关。模拟结果用于解释可用的实验数据并提出缺口敏感性的评估程序。
Matrix cracking, fiber breaking and interface sliding cause nonlinear deformation in fiber-reinforced brittle matrix composites. When a notched sample is loaded in tension, the nonlinear deformation usually localizes around the notch, spreads the stress in the ligament more evenly, and thereby leads to a higher fracture load. We simulate the interplay of two deformation mechanisms: a tensile band ahead of, and shear bands perpendicular to, a notch. The shear deformation evens out the stress distribution in the tensile band, and the strength of the tensile band sets the extent of the shear deformation. Each band is simulated by a traction-deformation law. The work of fracture is computed from a small-scale inelastic problem, and the fracture loads of notched samples from a large-scale inelastic problem. Several important conclusions emerge from the simulation. First, weak shear bands can substantially increase the work of fracture. Second, the fracture loads of notched samples are well correlated with the unnotched strength, work of fracture and notch size, by a formula independent of the shear band description. The results of the simulation are used to explain the available experimental data and to suggest an evaluation procedure for notch-sensitivity.