MINIMAL EXPERIMENTAL CHARACTERIZATION FORACCURATE NUMERICAL PREDICTION OF THE CURE-INDUCEDDEFORMATIONS IN COMPOSITES

Composite parts generally build up internal stresses as they cure and, hence, deform as they are demoulded. As a consequence, the geometry of the final part can significantly depart from the nominal design. In rather simple cases, the geometry of the mould can easily be modified based on rules-of-thumb to compensate for these deformations. In more complex cases, simple rules-of-thumb are not available such that several error and trial steps are required to compensate for the cure-induced deformations. A possible way of reducing the cost of these numerous trial and error steps is to get an accurate prediction of these deformations by numerical simulation. Several potentially suitable models can be found in the literature. However, they all carry the same burden: they require a large number of material parameters as inputs and, hence, expensive experimental characterization campaigns. In the present study, a methodology is proposed to reduce the number of material parameters that need to be characterized experimentally. It is illustrated on L-beams made of either 8 or 12 layers of satin 5 weave, all oriented at either 0/90 or ±45 degrees, and which exhibit a spring-in angle after demoulding. This research was carried out in the frame of the EASI-PM project funded by the Walloon Region (Belgium).