Introduction to Aerospace Materials

20

Fatigue of aerospace materials

20.1 Introduction

Fatigue is the most common cause of damage to aircraft structures and engine components. It is estimated that fatigue causes over one-half of all metal component failures, and is responsible for more damage than the combined effects of corrosion, creep, wear, overloading and all the other failure sources on aircraft. For example, a study performed on repairs made to the aluminium fuselage of 71 Boeing 747 aircraft with an average life of nearly 30 000 flight hours revealed that the most common type of damage was fatigue cracking (58% of all repairs), followed by corrosion (29%) and then impact damage from bird strike (13%). Fatigue is also damaging to composite structures, although the incidence ...