Tension–Tension Fatigue and Flammability Behavior of Fire-Resistant Carbon Fiber Composites for Fire Drone Applications

This study examines the fatigue and flammability performance of TC1810/T1100GC fire-resistant carbon fiber composites used in structural components of firefighting and fire surveillance drones. These systems operate in high-temperature environments where materials must endure repeated tensile and flexural loads. Composite laminates with a [0/90]6S stacking sequence were fabricated and tested under load-controlled tension–tension fatigue conditions, using a sinusoidal waveform at a frequency of 5 Hz and a stress ratio of R = 0.1. Additionally, static tensile and flexural properties were evaluated. Thermal behavior was characterized using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The flame retardancy was evaluated using Limiting Oxygen Index (LOI) testing. The material exhibited has LOI greater than 50%, confirming its strong flame retardancy. Fatigue life decreased with increasing stress levels, while specimens at 40% of ultimate tensile strength (UTS) survived one million cycles without failure. Stiffness degradation trends revealed early-stage matrix damage followed by gradual fiber–matrix debonding. These results demonstrate that TC1810/T1100GC composites provide a favorable combination of mechanical endurance and fire resistance, making them suitable for use in aerial systems functioning in thermally and mechanically demanding environmental conditions.