Damage tolerant design and nondestructive inspection core. Impact resistant and damage tolerant aircraft fuselage us12. Volume i introduces the damage tolerance concept with a historical perspective followed by the fundamentals of fracture mechanics and fatigue crack propagation. Aircraft components under static service loading using genoa with and without umat. Each failure was precipitated by the accumulation of undetectable fatigue damage. Damage tolerant design and nondestructive inspection are key tasks for ensuring aircraft airworthiness. Book 3 provides a method and design data for damage tolerance analysis of metallic structure. Damage tolerant composite design principles for aircraft components under static service loading using multiscale progressive failure analysis alphastar corporation long beach, ca, usa. Although damage tolerance as we know it today is a relatively new technology, its importance was recognized as long four centuries ago. Damage tolerant composite design principles for aircraft.
Damage tolerance analysis dta was considered in the global design optimization of an aircraft wing structure. Damage tolerant design of turbine engine disks turbo. The purpose of this paper will be the definition and standardization of procedures to be followed by an aircraft contractor, ogma, in order to implement a damage tolerant design for the components. Damage tolerance is the ability to resist fracture from. This is the first edition of a handbook to support the usaf airplane damage tolerance requirements contained in mila83444. Keep in mind that typical fatigue analysis of aircraft structures. Usaf damage tolerance methods applied to general aviation. Dotfaaar0155 probabilistic design of damage tolerant. Forty years of structural durability and damage tolerance. Awareness of problem areas and regulatory requirements for fatigue and damage tolerant design in aircraft. The redesigned disk was tested to failure while monitoring crack growth and correlating observed measurements with analytical prediction. Pdf damage tolerance of aircraft panels researchgate. Pdf on may 22, 2002, damir jelaska and others published damage tolerant design of the aircraft components find, read and cite all the.
Probabilistic manufacturing tolerance optimization of damagetolerant aircraft structures using measured data k. However, that damage is detected and repaired within the safety limits placed. Worked examples and handson experience of solution methods and procedures in structural fatigue, damage tolerance problems and airworthiness issues in aircraft structures. Fatigue and damage tolerance analysis aeronautics and. In addition to accuracy, computational costs in relation to. J p gallagher f giessler alan p berens john m engle about. The concept requires repeated, routine inspections of the structure to evaluate any damage and repair it before return. Damage tolerant design and nondestructive inspection. Easy construction high weight to strength ratio circular. Damage tolerant no set life assigned to the aircraft. The advent of damage tolerant design in modern transport category airplanes further complicated the approval procedures for repairs by introducing the need for additional testing andor analysis in order to assess the long term effects of repairs on damage tolerant structure. The globallocal finite element approach allowed local fatigue requirements to be considered in the global design optimization.
Similar to the boeing durability method, the boeing damage tolerance approach was first implemented for new design with the 757 and 767 models. As previously discussed in the introduction section, the damage tolerance methodology plays a fundamental role in the design process of a. Ali fatemi university of toledo all rights reserved chapter 2fatigue design methods 3 fatigue design flow chart. Latest aircraft design is called the damage tolerant design, which require. Efficient and damage tolerant wingfuselage integration structure, applicable to the next generation of transport aircraft, will facilitate the realisation of the benefits offered by new aircraft concepts. Pdf on apr 21, 2010, p m s t castro and others published damage tolerance of aircraft panels find, read and cite all the research you need on researchgate. Near the end of the fifteenth century, technical notes were written on what must have been one of the first requirements for damage tolerant design.
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. This damage tolerance assessment handbook consists of two volumes. Aircraft components under static service loading using. Current work involves extending damage tolerant design capability to hotsection powdermetallurgy disks. Outlineoutline boeing design criteria for damage tolerant cfrp primary structures and the relationship to. Adoption of formal fatigue requirements in the design to prevent. International conference on damage tolerance of aircraft structures. The aircraft is built strongly enough to last a pre. Damage tolerance is the ability to resist fracture from preexistent damage for a given period of time and is an essential attribute of components whose failure could result in catastrophic loss of life or property. Will not accept composite structures that are less damage tolerant than metals. Residual strength and fatigue life requirements, based on the damage tolerance philosophy, were investigated as new design constraints. The purpose of this paper is to present some guidance to usaf experience and expertise in damage tolerant design philosophy and applications to the general aviation community.
In addition to the web pages, each section of the handbook, as well as the sample problems, is available as a file in. While nextgeneration aircraft are expected to use laminated or tailored composite skin structure that is more damage tolerant, there are many lessons that have been learned in maintaining and repairing the thinskin, nonmetallic honeycomb sandwich constructions on todays aircraft that need to be considered in new aircraft design and materials. Introduction fracture mechanics fatigue crack propagation. Damage tolerance safetyofflight composite aircraft structure should be designed damage tolerant the damage tolerance evaluation should. Three critical issues associated with damage tolerant design are. Probabilistic manufacturing tolerance optimization of. To answer these questions, a building block approach is adopted. White paper fatigue and damage tolerance analysis of aircraft. Damagetolerant design an overview sciencedirect topics.
Various fracture criteria and crack growth rules are studied. Probabilistic approach to damage tolerance design of. Design and analysis of aircraft structures 439 structure must be damage tolerant design requirement structure must have capability to withstand damage until detected and repaired. In addition, background data culled from russian usage of composite aircraft structures was compiled to use with prodecompos.
Aircraft fatigue and damage tolerance cranfield university. Revision b by defense technical information center. This ac will give guidance on developing compliance documents, schedules and plans that will assist in developing and incorporating damage tolerance inspections into maintenance programs of certain transport category airplanes with respect to repairs and alterations. Damage tolerance of aircraft panels 37 the concept of safety factor in safe life design or in damage tolerant design is different. Results of displacement compatibility analysis, representing a variety of repair doubler and lap splice configurations, are presented to illustrate how structural repairs can degrade the fatigue initiation life and damage tolerance capability of primary transport aircraft structure. In addition, background data culled from russian usage of composite aircraft structures was. Damage tolerance considerations in composite aircraft. Durability and damage tolerance control plans for u. Analytical approach damage tolerance is verified by analytical assessment of damage growth, residual strength, and surveillance. Dtics pdf and excel spreadsheet versions of congressional budget reports are available shortly after postings on thomas library of congress website. Ac 12093 damage tolerance inspections for repairs and. A key element is the development of a comprehensive programme of inspections to detect cracks before they. A damagetolerance attachment system for an aircraft engine includes first and second attachment devices attaching the aircraft engine to a pylon fixedly attached to the aircraft, and a third backup attachment device including a first portion attached to the pylon and a second portion attached to the engine, the first and second portions connected together loosely so as not to disrupt an. Aircraft maintenance inspection has been changing along with the development of aircraft design and maintenance method.
Pdf damage tolerant design of the aircraft components. Air force approach to aircraft damage tolerant design by mitchell p. Strict requirements have been established for durable and damage tolerant designs by both military and civilian regulatory agencies such as the faa and jaa. Advanced durability and damage tolerance design and. Damage tolerance was formally adopted by the air force as part of the airplane structural integrity program asip milstd1530, 1972 and was implemented. Wing joint design is one of the most critical areas in aircraft structures. Guidelines for the analysis and design of damage tolerant aircraft structures. Boeing composite airframe damage tolerance and service. Summary of sections of damage tolerance design handbook. It provides specific background data and justification for the detailed requirements of mila83444 and provides guidelines and stateoftheart analysis methods to assist contractor and usaf personnel in complying with the intent of the specification and in solving. Styuart university of washington, seattle, wa, 981952400 a probabilistic approach to determine design parameters for damagetolerant composite aircraft structures has been developed. Usaf damage tolerance methods applied to general aviation aircraft design and analysis 850915. Boeing composite airframe damage tolerance and service experience allen j. It is considered firstly that this structural design provides the aircraft fuselage part 31 with a high torsional strength to deal with an event of detachment of a propeller blade 15 from an engine causing on one side a torsion over the.
It discusses the use of fracture mechanics as a method of predicting failure, understanding failure mechanisms, and suggesting inspection. Examples show that fatigue initiation life is directly related to the peak loads induced in the first fastener. Book 3 was also used concurrently for supplemental structural inspection programs on the 727, 737 and 747. Based upon the above statement, requirements as shown below follow. A key element is the development of a comprehensive programme of inspections to detect cracks before they can affect flight safety. Md88 aircraft in 1996 illustrate the need to design both durable and damage tolerant primary structure. Probabilistic approach to damage tolerance design of aircraft composite structures kuen y. Near the end of the fifteenth century, technical notes were written on what must have been one of the first requirements for damagetolerant design. 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. Test results were used to refine the design system. Although the usaf fleet is much more tightly controlled in its. Two major structural design drivers for both commercial and military aircraft gas turbine engines are. The guidelines apply to all safety of flight structure, i.