Edgewise compressive performance of repaired composite sandwich panels - Experiment and finite element analysis

Bonded repair was conducted to composite sandwich panels with one side skin and full-depth core penetrated damage. Experiments on edgewise compressive behavior of repaired panel were carried out and influences of various repair parameters including different repair materials (high or medium temperature cured pre-preg), different taper ratios for scarf repair (1/30 or 1/10) and different repair techniques (scarf or step repair) were compared. Based on continuum damage mechanics, a three-dimensional finite element model was developed and a good agreement of experimental results with numerical predictions was obtained. With the analysis model, ultimate loads, damage evolution processes and adhesive stress distributions of repaired sandwich panels were investigated. The results of this study have provided an insight into the mechanical performance of repaired sandwich panels under edgewise compressive load, which could lead to improved design and analysis methodologies on the bonded repair of composite sandwich structures.