Optimization of damage parameters in glass fiber-reinforced composites: numerical and experimental insights into structural integrity enhancement

To optimizing damage tolerance in glass fiber-reinforced composites (GFRP) by introducing a novel evaluation of damage shape and size effects on different stacking sequences through combined experimental and numerical methods.GFRP are widely used in structural applications for their high strength-to-weight ratio and durability. Understanding their damage processes is essential for improving impact resistance and long-term performance. A holistic approach combining experimental testing, regression modeling, and numerical simulations was employed to investigate the influence of damage area, shape, and stacking sequence (bidirectional, unidirectional, and cross-ply) on residual strength. The analysis included GFRP samples with widths ranging from 25 mm to 50 mm and damage areas of 400 mm2, 200 mm2, and 100 mm2. Damage shapes examined included circular, square, rectangular, and elliptical geometries. Numerical simulations using ANSYS software identified the optimal shape for damage tolerance, which was then validated experimentally. Results showed that a 200 mm2 vertical elliptical damage design improved flexural strength by approximately 8–12% compared to circular and horizontal elliptical shapes, while horizontal elliptical designs reduced strength by nearly 10%. This research provides valuable insights into optimizing damage parameters for enhancing the structural integrity of GFRP laminates. The innovation of this work lies in linking geometric damage characteristics with stacking sequences, supported by predictive regression models (R2 > 0.95) and validated simulations (<5% deviation), thereby solving a key technical problem in composite repair. The conclusions underline the potential industrial relevance of these findings, particularly for aerospace, automotive, and civil engineering sectors where reliable and durable composite repairs are essential