Apr 28, 2006 designed to help students get a solid background in structural mechanics and extensively updated to help professionals get up to speed on recent advances this second edition of the bestselling textbook mechanics of aircraft structures combines fundamentals, an overview of new materials, and rigorous analysis tools into an excellent onesemester introductory course in structural mechanics and. A key element is the development of a comprehensive programme of inspections to detect cracks before they can affect flight safety. The use of a damage tolerance analysis methodology to accomplish these goals is described. Grihon1 1 airbus france, toulouse this report is based on a journal article published in the aeronautical journal, 118 1199, 31 52, 2014. Damage tolerance evaluation damage tolerance the damage tolerance evaluation of structure under the typical load and environmental spectra expected in service is intended to ensure, that should fatigue, intrinsicdiscrete damage, large area manufacturing flaws, or severe accidental damage occur within the operational life of the aircraft, the. The symposium, hosted by the faa center of excellence for computational modeling of aircraft structures at georgia institute of technology, was held to disseminate information on recent developments in advanced technologies to extend the life of hightime aircraft and design longerlife aircraft. The symposium on damage tolerance in aircraft structures was conducted in two sessions at the seventythird annual meeting of the american society for testing and materials, held in toronto, ontario, canada, 2126 june 1970. In addition, over the years, major airplane accidents have highlighted problems due to aging airplane structures including airframe structural fatigue, and issues. As part of the aircraft structural integrity program asip, an analytical methodology was developed for predicting the onset of widespread fatigue damage. Airbus damage tolerance methodologies for composite structures dong sheng li airbus d2, new technical centre, airbus uk, filton, bristol bs99 7ar, united kingdom dong. Prior to the 1970s, the prevailing engineering philosophy of aircraft structures was to ensure that airworthiness. Damage tolerance evaluation of the front spar in a transport. In this paper, issues related to the methodology, design, and state of the art of damage tolerance are examined. Multiplesite damage of aircraft structure pdf, office of aviation research, us department of transportation.
The joint advanced materials and structures center of excellence 3 primary objective develop a probabilistic approach to synthesize life factor, load factor and damage in composite structure to determine fatigue life of a damage tolerant aircraft demonstrate acceptable means of compliance for fatigue, damage tolerance and static. This advisory circular ac provides guidanc for compliance with the provisions of title 14, code of federal regulations 14 cfr part 25, pertaining to the requirements for damagetolerance and fatigue evaluation oftransport category aircraft structurce, including evaluation of widespread fatigue dam, age vlfd and establishing a limit of. Advances in materials and processes used to construct aircraft have led to their evolution from simple wood truss structures to the sleek aerodynamic flying machines of today. In parallel, engineering practice involving damage tolerance requires numerical techniques for stress analysis of cracked structures. A new approach to evaluate durability and damage tolerance for aircraft composite structures 37 10 100 1 10 100 1,000 10,000 100,000 1,000,000 10,000,000 cycles to failure a p pl i e d s t r e s s m p a logf2. The maximum permissible surface dent sizes in composite struct ures are usually specified in terms of surface flaw depth, and flaws deeper than this must be repaired within a time or cycles limit. Proceeding of the faanasa symposium on the continued airworthiness of aircraft structures. Modern jet transport aircraft structures, although certified in accordance with current regulations, have been designed using damagetolerance practices which resulted in an excellent safety record. The increase of service life by replacing the riveted structure by a bonded structure makes it worthwhile to explore the bonding technology further than the. Damage tolerance philosophy damage tolerance is a safety requirement and equates to the fail safe design approach employed for flight critical components by the rotary wing industry since the early 60s. Probabilistic manufacturing tolerance optimization of. Paper 20 03 reliability of damage detection in advanced.
Introduction fracture mechanics fatigue crack propagation. The composite materials response 22nd plantema memorial lecture problem area this report contains the second international committee on aeronautical fatigue icaf plantema memorial lecture. The first implies evaluations of uncertainties associated with life estimation, whereas the second implies monitoring processes such as to ensure continued structural integrity, bristow and irving, 2007. N recent years, aircraft reliability and risk assessment are becoming more accepted in the areas of structural integrity and fleet management. Volume i introduces the damage tolerance concept with a historical perspective followed by the fundamentals of fracture mechanics and fatigue crack propagation. Torsional stress in a fuselage is created in several ways.
Should new information, coming from such sources as a nation science foundation study group, provide additional relevant data, our analysis should be quickly. Dec 11, 20 damage tolerance of cargo aircraft structures g. Probabilistic manufacturing tolerance optimization of damagetolerant aircraft structures using measured data k. Any new aircraft program is based on assessing structural design information, fatigue and damage tolerance evaluations, service. In particular, the key features associated with the definition of such a design approach for composite structure can be summarized as follows. Otherwise, cost and schedule can be adversely impacted due to drawing andor tooling changes necessary to meet customer damage tolerance requirements. Designed to help students get a solid background in structural mechanics and extensively updated to help professionals get up to speed on recent advances this second edition of the bestselling textbook mechanics of aircraft structures combines fundamentals, an overview of new materials, and rigorous analysis tools into an excellent onesemester introductory course in structural mechanics and. Recent advances in durability and damage tolerance methodology. Plantema was deeply convinced that sharing practical experience and academia research on a much broader range was essential to overcome fatigue of structures. But in spite of so much progress, there are still many conferences on fatigue problems of aircraft structures.
It is the stress that resists the force tending to cause one layer of a material to slide over an adjacent layer. These panels were designed to meet end load and stiffness requirements of current commercial transport aircraft and to provide damage tolerance with respect to external skin damage. Damage tolerance testing of composites not standardized until 2005, astm d 77 is still commonly referred to as the boeing cai test. In spite of these practices unpredictable cracks and corrosion occur in. Damage tolerance of composite laminates from an empirical. Mechanical fastening remains the state of the art joining method for primary airframe structures, whether it is. The main spar takes a maj or portion of this bending moment. Damage tolerance of metallic aircraft structures materials and. Identify key similarities and differences in methods used to substantiate damage capability for transport aircraft composite structures.
The contents of this report may be cited on condition that full credit is. Aircraft life monitoring there are 3 philosophical approaches to designing aircraft in order to ensure that they operate safely throughout their operational lives. One key technology for the future development of composite aircraft structures is a suitable joining technology. A new approach to evaluate durability and damage tolerance.
Probabilistic manufacturing tolerance optimization of damage. Fail safe structures have multiple load paths and if one part fails, other components will take over the load eg multiple attachment points for. Once the procedure is approved by the aeronautical authorities it will have significant impact on costs reduction, without compromising the safety of the repairs. Visual inspection is the first line of detecti on for damage on aircraft structures. Durability and damage tolerance ot pr large composite ne. Fatigue and damage tolerance analysis aeronautics and. Probabilistic approach to damage tolerance design of aircraft composite structures kuen y. Development of failsafe and damage tolerance design methods, which recognise that airframe structures must withstand service loads even. Fatigue and damage tolerance evaluation of structures. Damage tolerance is a property of a structure relating to its ability to sustain defects safely until. White paper fatigue and damage tolerance analysis of aircraft. His research and teaching work has been with both metallic and.
Damage tolerance and fatigue evaluation of structure federal. Analysis of requirements on fatigue and damage tolerance for. Fatigue behavior and damage tolerant design of bonded joints. Milestone case histories in aircraft structural integrity. Nesterenko journal of machinery manufacture and reliability volume 42, pages 521 526 20 cite this article. The damage tolerance approach is based on the principle that while cracks due to fatigue and corrosion will develop in the aircraft structure, the process can be understood and controlled. I fatigue and damage tolerance of aging aircraft structures. Aircraft structure with fatigue crack growing from radius to fastener hole experience swri has performed damage tolerance and fatigue analysis for u. Facilities and analysis tools swri uses stateoftheart crack growth analysis tools.
Fatigue and residual strength of composite aircraft structures diva. Apr 20, 2014 11 aircraft structures chapter 1 a brief history of aircraft structures the history of aircraft structures underlies the history of aviation in general. Fatigue damage in aircraft structures, not wanted, but tolerated. Faaeasaboeingairbus damage tolerance and maintenance. It covers all fundamental subjects, including elasticity, structural analysis, airworthiness and aeroelasticity. For the continued airworthiness of an aircraft during its entire econom ic service life, fatigue and damage tolerance design, analysis, testing and service experience correlation play a pivotal role. The maximum permissible surface dent sizes in composite struct ures are usually specified in terms of surface flaw depth, and flaws deeper than this must be. Nesterenko moscow institute of physics and technology state university department of aerodynamics and flight engineering, russia keywords. Damage tolerance testing and analysis protocols for full. Probabilistic approach to damage tolerance design of. Damagetolerance practices applied to transport aircraft. Adams is a professor of mechanical engineering and has been the director for 20 years of the composite mechanics laboratory at the university of utah and vice president of wyoming test fixtures inc.
This damage tolerance assessment handbook consists of two volumes. Analytically experimental study of damage tolerance of aircraft structures mr. Apparently significant improvements of designing aircraft against fatigue have been made. Emeritus professor phil irving, formerly head of damage tolerance group at cranfield, phil has been teaching, researching and publishing in the field of fatigue, structural integrity and damage tolerance in aircraft structures, both in industry and academia for the past 30 years. Damage tolerance is a property of a structure relating to its ability to sustain defects safely until repair can be effected. Description design, analysis and testing fundamentals are used as an introduction to the effects of fatigue and accidental and corrosion damage on the durability and damage tolerance of aircraft structure. The importance of addressing damage tolerance early in the design process is emphasized. Comment on the damage tolerance philosophy many programs follow composite materials handbook17 formerly mil17 this information is presented from the perspective of aircraft structures, since that is the authors background authors recognize document is airplane specific it is notrequirementsno shall statements, it is a. A key element is related to the definition of damage tolerance. These evolved from basic mode i evaluations using rough finite element approaches, to current 3d modeling based on energetic approaches as the vcct, or simulation of joining processes. P1 p as the use of composite materials in aircraft structures are becoming more widespread, a greater need exists to determine the reliability of aircraft structures subject to accidental damage. Probabilistic approach to damage tolerance design of aircraft. Chapter 2aircraft structure introduction an aircraft is a device that is used, or intended to be used, for.
The key features associated with a definition for composite structures can be summarized as follows. A key element is the development of a comprehensive programme of inspections to detect cracks before they. Dotfaaar972, ii proceedings of the office of aviation. Damage tolerance of aircraft structures sciencedirect. Efficient optimisation of large aircraft fuselage structures. Damage tolerance is the ability of the structure to resist failure due to the presence of. Materials and numerical modelling springerbriefs in applied sciences and technology tavares, sergio m. Identify the key elements necessary to substantiate maintenance. At that time, a hundred percent of the commercial and military aircraft structures were made out of metal and dr. Damage tolerance considerations in composite aircraft. Damage tolerance philosophy for bonded aircraft structures 7 adherent can be equated to the elongation of the uncracked adherent over the delamination length, b, plus the shear deformation of the adhesive layer.
Various fracture criteria and crack growth rules are studied. Aircraft structures for engineering students 6th edition. Damage tolerance of bonded aircraft structures sciencedirect. The paper is mostly focused towards wing structures, particularly.
Aircraft structures for engineering students, sixth edition, is the leading selfcontained aircraft structures course text. Damage tolerance the damage tolerance evaluation of structure under the typical load and environmental spectra expected in service is intended to ensure, that should fatigue, intrinsicdiscrete damage, large area manufacturing flaws, or severe accidental damage occur within the operational life of the aircraft, the remaining structure will. The fuselage of an aircraft is subject the fives types of stresstorsion, bending, tension, shear, and compression. Design and analysis of aircraft structures 437 damage tolerance regulation comparison related to structural damage characteristics and past service history initial faa engineering and air carrier approval based on service history faa air carrier approval inspection program. Request pdf fatigue crack growth history in damage tolerance design of aircraft structures knowing the real history of the fatigue process is a valuable asset to the for design, development. In a transport aircraft there are usually two spars to take the bending loads.
Kim university of florida, gainesville, florida 32611 and c. Aircraft structures certification fatigue and damage tolerance evaluation of structures. Department of transportation federal aviation administration notice. Aircraft fatigue and damage tolerance cranfield university. Damage tolerance of cargo aircraft structures springerlink. The symposium was sponsored by astm committee e09 on fatigue. Review of damage tolerance for composite sandwich airframe structures august 1999 final report this document is available to the u. Damage tolerance of aircraft panels 37 the concept of safety factor in safe life design or in damage tolerant design is different. The approach to engineering design to account for damage tolerance is based on the assumption that flaws can exist in any structure and such flaws propagate with usage. A method for reliability assessment of aircraft structures.
Fatigue crack growth history in damage tolerance design of. Integrity program asip, initiated in 1958, was based on a fatigue initiation approach and was moderately successful. Efficient optimisation of large aircraft fuselage structures w. Durability and damage tolerance concepts for aging aircraft. Hurst cessna aircraft company, wichita, kansas 67215 doi. Styuart university of washington, seattle, wa, 981952400 a probabilistic approach to determine design parameters for damagetolerant composite aircraft structures has been developed.
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