Mechanical performance of glass fiber epoxy laminates with embedded circular and square cutouts

Abstract. This study explores the influence of induced embedded cutouts of circular and square shapes on tensile and buckling performance of glass fiber reinforced polymer (GFRP) composite laminates. Cutouts are often introduced in composite structures during manufacturing for functional requirements such as fastening, wiring, or integration with other components. But their presence creates a localized stress concentration that can significantly affect mechanical performance and failure behavior. Specimens with embedded circular, square shaped cutouts, and plain GFRP composite laminates were manufactured and tested under tensile and buckling load conditions to assess the extent of strength reduction. The results demonstrate that embedded circular holes cause a decrease in their tensile and buckling strengths up to 51% compared to plain laminates, as their geometry facilitates uniform stress distribution and reduces the likelihood of premature failure. In contrast, square cutouts lead to a more pronounced reduction up to 55% in both tensile and buckling strength, this was primarily due to the sharp corners serving as stress risers hence initiating damage and propagate the cracks. This study provides detailed insights into the behavior of GFRP laminates with embedded features and highlights the importance of optimizing the design for placement of cutouts through experimental and finite element analysis to balance functional requirements with mechanical reliability in engineering applications.