Study On Curing Deformation Of Composite Structural-similar Scaled Model Of Wing

The wind-tunnel tests in purpose of acquiring the aero-elastic feature of aircrafts are considered as a major part of modern aircraft designing business. Being the testing subject of wind-tunnel test, scaled physical model of aircrafts should provide aero-elastic feature and aerodynamic contour with high level of similarity to the original aircrafts design. In recent studies of wind-tunnel test, the focus of aeronautical material science, composites of multi-phase materials were used as the structural material choice for scaled model manufacturing, and the comprehensive feature of advantageous feature of multi-phase material were shown. Correspondingly, scaled models made of composites showing high degrees of mechanical feature designing possibilities present academic value in aircrafts aero-elastic researches.The composites material mentioned in this dissertation are fiber-reinforced plastics which were manufactured in the way of composites molding. The thermosetting resin used in composites molding shows curing process of highly complex feature of chemical fields, physical fields and mechanical fields coupling. During the curing process, the material mechanical feature and physical feature are changing radically. Because of the huge gap between thermo expansion features between fibers and resin, along with the chemical shrinkage and molding effect, curing stress exist in the parts of composites structure. While in the moulds, the composites structure are restrained so that large scale of deformation would not happen, however, the composites structure would show deformation after being taken out of the mould when the curing process is finished. This geometrical contour and mechanical feature of scaled model would be out of the tolerance of requirements.Because of the deformation of curing in composites structure manufacturing process, the precision of geometrical feature and aero-elastic feature are affected, which would lead to improbable wind-tunnel test data. In purpose of evaluating the deformation of fiber-reinforced plastic in curing process and forecasting the deformation of composites scaled model, the relationship between composites curing stress and composites structure deformation should be studied. In this dissertation, the embedded-strain-gage techniques were used to evaluate the curing residual stress and curing deformation of composites. The epoxy resin, the uni-directional composites, orthotropic composites of glass fiber and epoxy resin and the orthotropic composites of carbon fiber and epoxy resin were tested to acquire the curing deformation. The mechanical parameters of composites after curing process were acquired through mechanical tensile tests. Correspondingly, the mechanical models of the curing residual stress and curing deformation were provided and the theoretical curing strain and curing stress were given. Basing on the data acquired, finite element simulations were applied to simulate the deformation of composites after the curing process was finished.Considering the cost of actual applying the manufacturing process of scaled model, finite element simulations instead of repeated manufacturing of scaled model were applied to forecast the deformation after the curing process.