Oblique Quasi-Static Indentation and Residual Compressive Behavior of Hybrid Woven Composite Laminates

The influence of oblique quasi-static indentation (QSI) angles on damage evolution and the residual compressive behavior of carbon-glass hybrid woven composite laminates is investigated. Hemispherical indentation tests were performed at 15° and 30° oblique angles, and three QSI specimens and two CAI (compression after Indentation) specimens were tested at each indentation angle, while CT analysis was performed on one representative specimen per angle. The results show that increasing the indentation angle had little effect on the peak indentation load but significantly increased the displacement at peak load and the total energy absorption. The CT analysis showed that the 30° indentation caused a wider and more distributed damage morphology compared to the localized damage pattern observed at 15°. Interestingly, the residual CAI strength of the 30° specimens was higher than that of the 15° specimens, which may be associated with the more distributed damage morphology and reduced severity of localized damage concentration. The progressive damage analysis using a homogenized ply-level Hashin progressive damage model implemented in Abaqus/Explicit is in good agreement with experimental results. These results provide insight into the mechanics of oblique contact damage in hybrid woven composites, which are important for damage-tolerant aerospace structural design.