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A time-dependent tensile constitutive model for long-fiber-reinforced unidirectional ceramic-matrix minicomposites considering interface and fiber oxidation
International Journal of Damage Mechanics ( IF 4.2 ) Pub Date : 2020-05-12 , DOI: 10.1177/1056789520924103
Li Longbiao 1
Affiliation  

In this paper, a time-dependent tensile constitutive model of long-fiber-reinforced unidirectional ceramic-matrix minicomposites is developed considering the interface and fiber oxidation. The relationship between the time-dependent tensile behavior and internal damage is established. The damage mechanisms of time-dependent matrix cracking, fiber/matrix interface debonding, fiber failure, and the oxidation of the interface and fiber are considered in the analysis of the time-dependent tensile stress–strain curve. The fracture mechanic approach, matrix statistical cracking model, and fiber statistical failure model are used to determine the time-dependent interface debonding length, matrix crack spacing, and the fiber failure probability considering the time-dependent interface and fiber oxidation. The effects of the fiber volume, fiber radius, matrix Weibull modulus, matrix cracking characteristic strength, matrix cracking saturation spacing, interface shear stress, interface debonding energy, fiber strength, fiber Weibull modulus, and oxidation time on the time-dependent tensile stress–strain curves, matrix cracking density, interface debonding, and fiber failure are discussed. The experimental time-dependent tensile stress–strain curves, matrix cracking, interface debonding, and fiber failure of four different unidirectional SiC/SiC minicomposites for different oxidation time are predicted. The composite tensile strength and failure strain increase with the fiber volume, fiber strength, and fiber Weibull modulus, and decrease with the oxidation time; the fiber/matrix interface debonding length increases with the fiber radius and oxidation time and decreases with the interfacial shear stress and interface debonding energy; the fiber/matrix interface oxidation ratio increases with the interfacial shear stress, interface debonding energy, and oxidation time and decreases with the saturation matrix crack spacing.

中文翻译:

考虑界面和纤维氧化的长纤维增强单向陶瓷基微型复合材料的瞬态拉伸本构模型

在本文中,考虑到界面和纤维氧化,开发了长纤维增强单向陶瓷基微型复合材料的时间相关拉伸本构模型。建立了随时间变化的拉伸行为与内部损伤之间的关系。时变拉伸应力-应变曲线分析考虑了时变基体开裂、纤维/基体界面脱粘、纤维失效以及界面和纤维氧化等损伤机制。使用断裂力学方法、基体统计开裂模型和纤维统计失效模型来确定时变界面脱粘长度、基体裂缝间距和考虑时变界面和纤维氧化的纤维失效概率。纤维体积、纤维半径的影响,基体威布尔模量、基体开裂特征强度、基体开裂饱和间距、界面剪应力、界面脱粘能、纤维强度、纤维威布尔模量和随时间变化的拉伸应力-应变曲线上的氧化时间、基体开裂密度、界面脱粘、和光纤故障进行了讨论。预测了四种不同单向 SiC/SiC 微型复合材料在不同氧化时间下的实验时间相关拉伸应力-应变曲线、基体开裂、界面脱粘和纤维破坏。复合材料的拉伸强度和破坏应变随着纤维体积、纤维强度和纤维威布尔模量的增加而增加,随着氧化时间的延长而降低;纤维/基体界面脱粘长度随着纤维半径和氧化时间的增加而增加,随着界面剪切应力和界面脱粘能的增加而减小;纤维/基体界面氧化率随着界面剪切应力、界面剥离能和氧化时间的增加而增加,并随着饱和基体裂纹间距的增加而减小。
更新日期:2020-05-12
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