DAMAGE TOLERANCE OF AIRCRAFT SANDWICH STRUCTURE - PRINCIPLE "FAIL-SAFE"

Fatigue represents progressive fracture mechanism and degradation of material characteristics starting from the first phase. Ensuring of airplane construction from catastrophically fracture influence due to fatigue requires specific theoretical approach and developing of additional security actions. "Fail-safe" design principle, which represents adequate security after defined level of defect, reduced problem concerning fatigue from security to economic level. The aim of this work is to help design engineers to better understand problem concerning fatigue, crack widening and "fail-safe" design principle of airplanes. For that purpose, two methods were analyzed to identify) and estimate damage tolerance of sandwich structure, which paralel results were discussed in this work.