A model on the curved shapes of unsymmetric laminates including tool-part interaction

Abstract

The room-temperature shape of unsymmetric laminate due to the residual stress developed during the curing process has been investigated in the past decades. The factors influencing the residual stress of unsymmetric laminate, including moisture, fiber orientation, aspect ratio and ply thickness, have been widely investigated. Another mechanism that can generate residual stress is the interaction between the tool and the composite part during heating-up process. In this work, the effects resulting from the interaction between laminate and tool during the heating-up phase were considered. By introducing an interfacial shear stress due to tool-part interaction, an analytical model based on the Extended Classical Lamination Theory of Dano and Hyer was proposed to predict the room-temperature shapes of cross-ply unsymmetric laminates. The interfacial shear stress, which was correlated with experimental results, was introduced to tailor the amount of residual stress transferred from the tool. The model was validated with experimental data provided in the literature. It is shown that this model which takes the tool-part interaction into consideration could predict part processing deformations more accurately.

Keywords

• composites
• interfacial shear stress
• tool-part interaction
• unsymmetric laminates