An approach to simulate the constitutive model of a unidirectionally SiC fiber-reinforced titanium matrix composite during spectrum loading was developed in this paper. Based on the assumption that there is a microcrack in the matrix and the maximum shear stress criterion, the debonding length and the distribution of interfacial slip zone under spectrum loading were derived. The stress at a loading point was divided into four stages including crack opening section, positive slip zone, reverse slip zone, and bond zone. Based on the partial crack shear-lag model, the stress of fiber and matrix in the four stages was derived, and the constitutive model of the composite under spectrum loading was established. At last, the effects of different damages on the constitutive model and interfacial debonding zone of a unidirectionally SiC fiber-reinforced titanium matrix composite were investigated.

提出了一种模拟单向SiC纤维增强钛基复合材料在光谱加载过程中本构模型的方法。基于基体中存在微裂纹和最大剪应力准则的假设，推导了谱载荷作用下的脱粘长度和界面滑移区的分布。加载点处的应力分为开裂区，正滑移区，反向滑移区和粘结区四个阶段。基于局部裂纹切变滞后模型，推导了纤维和基体在四个阶段的应力，建立了复合材料在频谱载荷下的本构模型。最后，