Control and analysis on residual deformation of fiber-reinforced polymer composites considering temperature cycle and pressure

Fiber-reinforced polymer composites are prone to cure deformation issues after manufacturing, which directly affects their engineering applications. To effectively control the deformation issues of composite laminates during the manufacturing process, this study focuses on glass fiber/epoxy composites, using asymmetric [90 5 /0 5 ] laminates to explore how temperature cycles and cure pressure impact deformation. The experimental results indicate that in the two-stage heating cycle, controlling the holding time in the first stage to cure the composite material to a state near the glass transition can more effectively reduce deformation. Compared to the standard temperature cycle, this temperature cycle can reduce the end deflection of the laminate by approximately 15.9%. Due to the inhibitory effect of pressure, when the cure pressure is increased from 0 MPa to 8 MPa, the end deflection of the laminate decreases by 59.4%. However, pressure introduces residual stress inside the material and retains this stress in a locked state within the material. The effect of post-curing on deformation exhibits significant condition dependency. For laminates manufactured without pressure and complete cure, the post-curing process reduces their deformation. In contrast, laminates subjected to pressure and failing to achieve full cure exhibit increased deformation after post-curing. Excessive pressure during cure even leads to torsional deformation after post-curing treatment.