ASSESSMENT OF IMPACT-RELATED FIBER FRACTURE AND MATRIX DAMAGE IN GFRP COMPONENTS USING THE SURFACE SANDBLASTING METHOD

Background: Glass Fiber-Reinforced Polymer (GFRP) composites are commonly used in aerospace, automotive, marine, and civil engineering because of their high strength-to-weight ratio and corrosion resistance. Despite these advantages, they remain susceptible to low-velocity impacts that can generate hidden internal damage including fiber fracture, matrix cracking, and fiber–matrix debonding which can significantly reduce structural performance. Method: This research evaluates a surface sandblasting technique aimed at improving the visibility and quantification of subsurface damage in plain-weave GFRP laminates with 8-, 10-, 16-, 18-, and 24-layers. After controlled drop-weight impacts, each specimen was gently sandblasted to remove the superficial resin layer and expose underlying micro-damage features. Results: Quantitative assessment shows substantial improvements in detection sensitivity after surface preparation. Fiber-fracture visibility increased from [Formula: see text]% to [Formula: see text]%, matrix-crack visibility from [Formula: see text]% to [Formula: see text]%, and debonding detection from [Formula: see text]% to [Formula: see text]%. Visible damage diameter also increased across all laminates (e.g. [Formula: see text] [Formula: see text]mm for 8-layers and [Formula: see text] [Formula: see text]mm for 18-layers), supporting clearer boundary identification and improved overall accuracy ([Formula: see text]% [Formula: see text]%). Conclusion: The findings confirm that surface sandblasting is a practical, cost-effective, and nondestructive technique that significantly enhances the assessment of impact damage in GFRP composites. Its ability to reveal previously obscured micro-damage supports more accurate structural health monitoring and long-term durability evaluation of GFRP components.