INFLUENCE OF PROCESSING DAMAGE ON PERFORMANCE OF FIBER-REINFORCED COMPOSITES
INFLUENCE OF PROCESSING DAMAGE ON PERFORMANCE OF FIBER-REINFORCED COMPOSITES
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DOI：
10.1016/0022-5096(94)00077-i
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发表时间：
1995-03
影响因子：
5.3
通讯作者：
W. Curtin;S. J. Zhou
中科院分区：
文献类型：
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作者：
W. Curtin;S. J. Zhou
加工引起的纤维损伤的影响，或等效的非连续增强复合材料中纤维长度的影响，对纤维增强陶瓷或金属基体的拉伸应力-应变行为的影响是由初始纤维损伤程度和原始纤维强度分布的函数确定的。该分析结合了对未损伤纤维问题的分析的概括[Curtin， W. a .（1991）陶瓷基复合材料力学性能理论]。j。陶瓷。[j] .岩石力学与工程学报。74,2837-2845]，并进行数值模拟，以预测应力-应变曲线、极限拉伸强度和应变、纤维拉拔和拉拔功。结果表明，使复合材料大幅削弱所需的初始损伤特征尺度始终为每长度1根纤维断裂δc，其中δ为未损伤复合材料的临界纤维滑移长度（通常为~ 1 mm）。总的来说，损伤对拉伸强度、破坏应变和拉拔的影响相当小，这是由于纤维/基体界面的抗滑性导致断裂纤维的承载能力。然而，复合材料的详细应力-应变行为被修改。该分析应用于Nicalon/CAS复合材料，其中已观察到“过早”纤维损伤。将初始纤维损伤纳入理论，准确地解释了在这种材料中观察到的过量应变、较低的切线模量和较低的极限强度（相对于没有初始纤维损伤的预测）。
The effect of processing-induced fiber damage, or equivalently the effect of fiber length in discontinuouslyreinforced composites, on the tensile stress-strain behavior of a fiber-reinforced ceramic or metal matrix is determined as a function of the extent of initial fiber damage and the pristine fiber strength distribution. The analysis combines a generalization of the analysis employed for the undamaged fiber problem [Curtin, W. A. (1991) Theory of mechanical properties of ceramic-matrix composites. J. Am. Ceram. Soc. 74, 2837–2845] and numerical simulations to predict the stress-strain curve, ultimate tensile strength and strain, fiber pullout, and work of pullout in terms of the underlying micromechanical material parameters. The results show that the characteristic scale of initial damage required to weaken the composite substantially is always of the order of one fiber break per length δc, where δcis the critical fiber slip length in the undamaged composite (typically ~ 1 mm). Overall, the effect of damage on tensile strength, failure strain, and pullout is found to be fairly small, which is attributed to the load carrying capacity of broken fibers due to the sliding resistance of the fiber/matrix interface. However, the detailed stress-strain behavior of the composite is modified. The analysis is applied to a Nicalon/CAS composite in which “premature” fiber damage has been observed. The inclusion of initial fiber damage into the theory accurately accounts for the excess strain, lower tangent modulus, and lower ultimate strength (relative to the predictions in the absence of initial fiber damage) observed in this material.