2018/4/27 圆上活发大学 Structural classification for damage tolerance 国上游文大逢 Structuralesanples Residual strength Wing fuel le Therefore,timely inspection is the key to ensure continued safe operation integrity B)Damage an Fatigue analysis orifod by tes design is ipractical Fatigue 国上活大学 Related Issues 圈上游大学 Definition:durability means the avoidance of fatigue ·Aging fleet program damage -Mandatory structure modification Damage features: -Mandatory corrosion prevention program Local fatigue damage -Structure repair procedures -Widespread fatigue damage ·Multiple sie damage Wide Spread Damage(WSD) -New inspection procedures to address concerns in similarly Multiple element damage stressed components ·Design methods Full-sc ale fatigue test twice the design service objective [50,000 flights or 20 years][FAA requirements for fatigue testing] -Boeing elects for TWICE the design service objective,i.e. 100,000 flights or 40 years Aging fleet program 27 Performance Requirements 国上我大峰 Structural Analysis 国上海大坐 Most weight efficient designs ·Durability Robustness ·Ease of maintenance ·Approach >Accurate prediction of external and internal loads Refined techniques for fatigue analysis >Reliable corrosion prevention Use of advanced materials >Integrated structural design And effective maintenance program sy-Dt.Wentin Song chool at and ronas 52018/4/27 5 © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Therefore, timely inspection is the key to ensure continued safe operation © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Structural classification for damage tolerance 26 Structural category Required design attributes Analysis requirements Structural examples Other structure (1) Secondary structure Design for loss of component or safe separation Continued safe flight Flap track fairings (2) Damage obvious or malfunction evident Design for failure or partial failure of a principal structural element with continued structural integrity Residual strength Wing fuel leaks Primary structure (Structurally significant items or principal structural elements) (3) Damage detection by planned inspection Inspection program matched to structural characteristics Residual strength Crack growth Inspection program All primary structures not included in (2) and (4) (4) Safe life design Design for conservative fatigue life (damage tolerant design is impractical Fatigue analysis verified by test Landing gear structure © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Fatigue • Definition: durability means the avoidance of fatigue damage • Damage features: – Local fatigue damage – Widespread fatigue damage • Multiple site damage • Multiple element damage • Design methods – Full-scale fatigue test twice the design service objective [50,000 flights or 20 years] [FAA requirements for fatigue testing] – Boeing elects for TWICE the design service objective, i.e. 100,000 flights or 40 years – Aging fleet program 27 © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Related Issues • Aging fleet program – Mandatory structure modification – Mandatory corrosion prevention program – Structure repair procedures • Wide Spread Damage (WSD) – New inspection procedures to address concerns in similarly stressed components © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Performance Requirements • Most weight efficient designs • Durability • Robustness • Ease of maintenance • Approach  Accurate prediction of external and internal loads  Refined techniques for fatigue analysis  Reliable corrosion prevention  Use of advanced materials  Integrated structural design  And effective maintenance program © Shanghai Jiao Tong University – Dr. Wenbin Song School of Aeronautics and Astronautics Structural Analysis