UNIFIED COMPUTATIONAL THEORY OF FRACTURE MECHANICS IN SHELL AND AIRCRAFT STRUCTURAL DESIGN

The fracture mechanics theory and methodology have played an irreplaceable role in aircraft structure design. According to fracture criterion, it is divided into preventing and driving crack propagation. The crack arrest is to prevent aircraft structure from catastrophic failure, which is the last safety defense line; for example, the fracture arrested design for wing and fuselage of important structures, damage tolerance design for wide spread fatigue, and so on. The driving crack propagation is the key technology to realize quick separation of structures; for example, interstage separation of carrier rocket, separation between satellite and rocket, escape and life-saving of pilot and astronaut, and so on. The plate and shell are main structural forms of aircraft. There is an important scientific significance and engineering worth for investigating fracture mechanics in plate and shell. The authors have proposed the unified computational theory of fracture mechanics in shell and developed the corresponding extended finite element method. Based on the theory and method, the fracture propagation and arrest analysis are expressed in a large deformation curved shell. The successful applications are exhibited for designing wing monolithic structural component of domestic large airplane, Tianhe kernel cabin structure and opening canopy life-saving system of the advanced trainer.