Bird impact testing and explicit FE analysis on glass fiber - PMI foam sandwich construction: Prediction of threshold velocity

Composite sandwich structures, consisting of a glass fibre reinforced polymer (GFRP) skin and a PMI foam core, are a viable option for radome construction. These structures are capable of meeting design requirements such as electromagnetic transparency and meet the structural airworthiness requirements for aerodynamic load and bird impact load. This study examines the dynamic characteristics of a composite sandwich panel made of GFRP skin and PMI core when subjected to bird impact and calculates the velocity at which the simulated bird can penetrate the panel. The impact resistance of 1 m × 1 m composite sandwich panels was evaluated at three distinct velocities: 82 m/s, 127 m/s, and 149 m/s. The bird failed to puncture the panel at speeds of 82 m/s and 127 m/s but pierced through at the speed of 149 m/s. A precise numerical model, created using LSDYNA, accurately simulates the bird impact test conducted at the specified velocities, resulting in a stronger correlation. Same finite element model is employed to determine the velocity at which a bird may pierce through a 1 m × 1 m sandwich panel consisting of GFRP skin and PMI core, known as the ‘A’ type sandwich panel. The panel is subjected to edge constrained conditions, and the calculated threshold speed at which the panel can withstand the bird hit is found to be 144 m/s.