Effect of IFSS on tensile strength of unidirectional fiber composites using 3D-FEM simulation
Effect of IFSS on tensile strength of unidirectional fiber composites using 3D-FEM simulation
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DOI：
10.1163/156855103322320383
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发表时间：
2003-01-01
影响因子：
2.9
通讯作者：
Kodama, H
中科院分区：
文献类型：
--
作者：
Goda, K;Miwa, Y;Kodama, H
建立了基于三维有限元分析的蒙特-卡罗模拟模型，研究了界面剪切强度（IFSS）对纤维六角排列单向复合材料拉伸强度的影响。模拟模型包括纤维，基体和界面元素，因此，纤维断裂，基体断裂和界面脱粘在加载过程中可以单独预测。模拟了硼/环氧复合材料在不同IFSS下的拉伸断裂过程和强度。结果表明，随着IFSS的减小，由于界面脱粘的发生，邻近断裂纤维单元的完整纤维的应力集中系数减小。然而，由于界面脱粘也会降低断裂纤维的承载能力，因此所有纤维体积分数的复合材料强度都会降低。另一方面，一个大的IFSS会导致许多基体断裂，因此，它会导致低复合材料强度。因此，中间IFSS增加复合材料的拉伸强度。这意味着必须有一个“最佳”的IFSS，诱导复合材料的最高拉伸强度。随着纤维体积分数的增加，最佳值向低值移动。这是因为在较高的纤维体积分数下，断裂纤维元件周围的基质变得更容易在剪切中断裂，因此增强了完整纤维上的法向应力。
A Monte-Carlo simulation model based on 3D-finite element analysis was developed to clarify the effect of interfacial shear strength (IFSS) on tensile strength of a unidirectional composite with fibers placed in a hexagonal array. The simulation model comprises fiber, matrix and interface elements; thereby, fiber breaks, matrix fractures and interfacial debondings during loading can be predicted individually. Tensile fracture processes and strengths of a boron/epoxy composite were simulated at various IFSSs. Results show that as IFSS decreases, stress concentration factors to intact fibers adjacent to a broken fiber element decrease because of occurrences of interfacial debonding. However, since interfacial debonding also reduces load carrying capacity in broken fibers, composite strength is reduced in all fiber volume fractions. On the other hand, a large IFSS causes many matrix fractures at once; therefore, it induces low composite strength. Thus, intermediate IFSSs increase tensile strength of the composite. This means that there must be an 'optimum' IFSS which induces the highest tensile strength of the composite. The optimum value shifts to a low value as fiber volume fraction increases. This occurs because the matrix around broken fiber elements becomes more apt to be broken easily in shear at a higher fiber volume fraction, therefore enhancing normal stress on intact fibers.