The Degradation in Load Carrying Capability of Delaminated Specimens

Polymeric composites find extensive usage in aerospace applications, and their performance is influenced by environmental conditions throughout their life cycle. This study focuses on assessing the performance of composite laminates under different environmental conditions to evaluate the load carrying capacity LCC due to delamination. The laminates were specifically designed to withstand high pressure and temperature, ensuring satisfactory performance throughout their service life. The specimens, prepared according to ASTM standards with a thickness of 3 mm, featured different fibre orientations between the upper and lower laminates, including 0/0°, 0/30°, 0/45°, and 0/60°. The change in the delamination growth behavior for specimens subjected to different initial delamination lengths (a0) was studied using pre and post-radiographic tests RT. The investigation encompassed a range of initial delamination lengths, from 70 mm to 110 mm, incremented by 10 mm. Notably, failure was observed in specimens with a 0/30º angle when the initial crack length a0 reached 110 mm, while specimens with a 0/60º angle failed at an initial crack length of 80 mm. Additionally, it was noted that the maximum force required for the 0/30º angle laminate was observed when the initial crack length was 70 mm.