Investigation of fracture behaviour of hybrid composite materials under compact tension

• Fracture behavior of five VARTM composites analyzed via compact tension tests. • Hybrid composites (BGE, BCGE) showed superior fracture toughness and energy dissipation. • Basalt/Epoxy had the highest fracture toughness (37.7 MPa√m) and energy release rate. • Hybrid composites exhibited mixed-mode cracks, improving energy dissipation and resistance. This study examines the fracture behavior of hybrid composite materials by analyzing the relationship between stress intensity factors, crack opening displacement, and critical energy release rates for compact tension specimens. Five types of composite laminates—Basalt/Epoxy (BE), Carbon/Epoxy (CE), Glass/Epoxy (GE), Basalt-Glass/Epoxy (BGE), and Basalt-Carbon-Glass/Epoxy (BCGE)—were fabricated using the Vacuum Assisted Resin Transfer Molding (VARTM) method. Compact tension (CT) tests were conducted using a Universal Testing Machine (Instron 8801), recording load and displacement data to calculate fracture toughness and energy release rates. The results revealed that hybrid composites (BGE and BCGE) showed better fracture toughness (29.73 MPa m and 30.95 MPa m , respectively), energy dissipation (220 kJ/m² and 230 kJ/m², respectively), and crack resistance than mono-fiber composites (GE). However, the BE composite exhibits the highest toughness (KQ of 37.7 MPa m ) and critical energy release rate (GQ of about 260 kJ/m²) among the mono-fiber composites, attributed to strong fiber-matrix bonding. The GE composite has the lowest value of critical energy release rate of 150 kJ/m² and stress intensity factor of 17.02 MPa m , Indicating that glass fibers have a lower capability to dissipate energy during crack propagation. The crack propagation behavior differed among the composites, with BE, CE, and GE showing linear crack paths, whereas the hybrid composites exhibited mixed-mode fracture patterns, improving energy dissipation and enhancing crack propagation resistance.