Analysis of Fatigue Crack Initiation of On-Condition Aircraft Structural Components

Abstract

This project aims to analyses the fatigue crack initiation of an on condition component and assigns more reliable and accurate inspection intervals to identify the failure soon after it occurs. The current method of maintaining On-condition parts of an aircraft involves the method of identifying the failed components after some time of its failure by next scheduled inspection of that component. The new method is introduced by this research to overcome the previous method and develop more accurate inspection intervals for those components. From this method the use of failed on condition components and the adverse effects that can occur from that particular components to other components such as excessive stresses that applies on the fail safe designs can be eliminated and increase the usability of the components for some extend. Other than this by identifying a miner failure of an on-condition component by the use of revalidation techniques the usage of the components can be extended. For the development of the new method the approach is taken by implementing Re- Engineering methods for such the components. The material behaviour under fatigue loads and the relationship between the fatigue, stress, material properties and life cycles are given by the Ramberg-Osgood Equation and Morrow equation. For the calculation the details such as mean stress of the component, Monotonic properties and cyclic properties of the material, strain-Life properties are required. After the calculation the life cycles for a fatigue crack initiation of that component can be identified and this data can be used for Maintenance program development of assigning inspection intervals