<p>The expansion section of an advanced engine nozzle is commonly fabricated from multilayer resin-based, fabric-reinforced composite materials containing multiple interfaces. During the curing process, interfacial stress mismatch and cracking may occur due to inappropriate structural design and heterogeneous material properties. Accurate monitoring of interfacial stresses during curing is therefore critical for assessing the structural reliability of multilayer composite nozzle expansion sections. In this study, a numerical model is proposed to investigate the interfacial stresses that developed during the curing of a conical expansion section fabricated from glass/carbon double-layer plain-woven fabrics. The accuracy of the model is validated by comparing numerically predicted interfacial stresses with experimental measurements. Using the validated model, the influence of prepreg tape width in the two layers on interfacial stress matching is examined. The results show that reducing the carbon-fiber tape width increases interfacial stress mismatch, whereas reducing glass-fiber tape width effectively mitigates stress mismatch. A theoretical analysis indicates that the magnitude of interfacial stress mismatch is governed by the elastic modulus and the tape width of the individual layers. The findings provide a theoretical basis for the structural design and fabrication of composite engine nozzle components.</p>