The traditional strength of material analysis of Aircraft structures, in many cases, leads to catastrophic failure and leads to underestimated lives and thus greater costs, so a different methodology was developed in fracture mechanics, Damage Tolerance Design. As per this theory, the designer no longer assumes a perfect component but instead, the existence of initial damage that can propagate. However, that damage is detected and repaired to prevent the structural instability within the safety limits placed. This paper presents the fundamentals of Fracture mechanics and Damage Tolerance analysis methodology in Aircraft structure.

The purpose of this paper is to provide guidelines and analysis methods that should aid engineering personnel to implement the Damage Tolerance methodology in Aircraft Structures design. Damage Tolerance is the ability of the design to prevent structural defects or cracks from causing catastrophic fracture when the airframe is subjected to flight or ground loads. Damage Tolerance methodology allows the designer to demonstrate through a calculation that some assumed pre-existing defect will not propagate to failure between two inspections, the first being assumed to be made at a time when the defect was at the threshold of detectability.