Grant: Discovery Grants Program - Individual
Royal Military College of Canada
$20,000.00
Fatigue behaviour of re-worked fastener holes in aluminum alloys
EF 2012-13
Résumé
This proposal is to study fatigue cracking and crack growth behaviour in re-worked fastener holes in aircraft aluminum specimens. The objective is to understand the fatigue cracking mechanisms involved and to develop analytical techniques to model and design repair schemes for aging aircraft.
The majority of fatigue cracks in conventional aluminum airframe structures emanate from fastener holes and are detected before reaching critical size. These holes are re-worked, generally by over sizing the hole to remove the fatigue damage; new fasteners are installed before the aircraft is returned to service. Re-working of a hole may also include one or more of the following: cold expansion to impart beneficial compressive residual stresses, interference fit fasteners to improve fatigue life, and interference fit bushings to improve stiffness, restore net section and improve the fatigue life. In this research, a step by step approach will be used to develop a finite element model for reworked fastener details supported by simultaneously measured experimental fatigue data collected on laboratory specimens. Processing variables will be examined to determine which techniques are most beneficial to life extension and which techniques are detrimental to re-worked hole repair schemes. Processing variables will include: edge distance, amount of cold expansion, and amount of interference fit.
The benefits to the aerospace industry, both military and civilian, are tremendous.
Conventional aluminum airframes continue to be produced in great numbers; for example, Boeing's production of the 737 and 747 remains exceptionally high. Furthermore, the Canadian Forces continues to operate and acquire new versions of aircraft such as the CC-130 (Hercules) and CH-148 (Chinook), and have to extend the lifetime of platforms such as the CF-188 (Hornet). Life extension technologies for this application are vital to ensure the safety and economy of Canada's air transport, search and rescue, and defence systems for many decades to come.
Programme
Discovery Grants Program - Individual
Bénéficiaire
Emplacement
Ontario, Canada
Type de bénéficiaire
Academia
Type
Grant
Source
NSERC's Awards Data
Tel que publié
Application id
239174-2011
Name nom
DuQuesnay, David
Department département
Mechanical Engineering
Organization id
30
Institution établissement
Royal Military College of Canada
Province en
Ontario
Province fr
Ontario
Country en
CANADA
Country fr
CANADA
Fiscal year exercice financier
2012
Competition year année de concours
2011
Award amount
20000
Program id
RGPIN
Program name en
Discovery Grants Program - Individual
Program name fr
Programme de subventions à la découverte - individuelles
Group en
Discovery grants programs
Group fr
Programmes de subventions à la découverte
Committee code
1512
Committee name en
Mechanical Engineering
Committee name fr
Génie mécanique
Area of application code
1208
Area of application group en
Advancement of knowledge
Area of application group fr
Avancement des connaissances
Area of application en
Materials sciences
Area of application fr
Sciences des matériaux
Research subject code
2100
Research subject group en
Mechanical engineering
Research subject group fr
Génie mécanique
Research subject en
Mechanical engineering
Research subject fr
Génie mécanique
Partie
2
Nb partie
5
Application title
Fatigue behaviour of re-worked fastener holes in aluminum alloys
Keyword
NSERC
Application summary
This proposal is to study fatigue cracking and crack growth behaviour in re-worked fastener holes in aircraft aluminum specimens. The objective is to understand the fatigue cracking mechanisms involved and to develop analytical techniques to model and design repair schemes for aging aircraft.
The majority of fatigue cracks in conventional aluminum airframe structures emanate from fastener holes and are detected before reaching critical size. These holes are re-worked, generally by over sizing the hole to remove the fatigue damage; new fasteners are installed before the aircraft is returned to service. Re-working of a hole may also include one or more of the following: cold expansion to impart beneficial compressive residual stresses, interference fit fasteners to improve fatigue life, and interference fit bushings to improve stiffness, restore net section and improve the fatigue life. In this research, a step by step approach will be used to develop a finite element model for reworked fastener details supported by simultaneously measured experimental fatigue data collected on laboratory specimens. Processing variables will be examined to determine which techniques are most beneficial to life extension and which techniques are detrimental to re-worked hole repair schemes. Processing variables will include: edge distance, amount of cold expansion, and amount of interference fit.
The benefits to the aerospace industry, both military and civilian, are tremendous.
Conventional aluminum airframes continue to be produced in great numbers; for example, Boeing's production of the 737 and 747 remains exceptionally high. Furthermore, the Canadian Forces continues to operate and acquire new versions of aircraft such as the CC-130 (Hercules) and CH-148 (Chinook), and have to extend the lifetime of platforms such as the CF-188 (Hornet). Life extension technologies for this application are vital to ensure the safety and economy of Canada's air transport, search and rescue, and defence systems for many decades to come.
