Damage tolerant design and nondestructive inspection keys. Volume i introduces the damage tolerance concept with a historical perspective followed by the fundamentals of fracture mechanics and fatigue crack propagation. Application of damage tolerant design in mechanical engineering. Advanced methodologies for fracture analysis and damage. Composite materials are being used in aircraft primary structures such as 787 wings and fuselage. Damage tolerant design and condition monitoring of. The handbook is a compilation of mechanical property data that are useful for damage tolerant design and analyses. Damage tolerant design and nondestructive inspection. This handbook supports the usaf airplane damage tolerance requirements contained in mila83444. Damage tolerant design and nondestructive inspection are key tasks for ensuring aircraft airworthiness.
Usually, stress corrosion cracks are considered to be brittle, i. Damage tolerant design and nondestructive inspection core. Damage tolerance design damage tolerance design for wing components procedure standardization bernardo vilhena gavinho lourenco abstract. Dayton univ oh research inst this report presents a compilation of mechanical property data that are useful for damage tolerant design and analyses. Application of damage tolerant design in mechanical. Near the end of the fifteenth century, technical notes were written on what must have been one of the first requirements for damagetolerant design. This report presents a compilation of mechanical property data that are useful for damage tolerant design and analyses. The safelife design technique is employed in critical systems which are either very difficult to repair or whose failure may cause severe damage to life and property. Damage tolerant composite design principles for aircraft components under static service loading using multiscale progressive failure analysis alphastar corporation long beach, ca, usa. Damagetolerant design practice accounts for initial flaws already existing in a structure or component, and fracture mechanics concepts are applied to characterize the initiation and growth of cracks from these flaws. Awareness of problem areas and regulatory requirements for fatigue and damage tolerant design in aircraft. Boeing composite airframe damage tolerance and service experience.
Damage tolerance, crack propagation, riveted joint, inspection chart. Composite material and bondlines ewea offshore 2015 copenhagen 1012 march 2015 fracture energy vs crack extension. Fatigue analysis of mechanical components, in many cases, leads to underestimated lives and thus greater costs, so a different philosophy was developed, damage. For this initial effort, crack growth rate data in the nasgro database, the united states air force damage tolerant design handbook, and other publicly available sources were examined and used to. Damage tolerance design for wing components procedure standardization. Damage tolerance is the loadcarrying capability of a structure once it has been damaged by service loads sierakowski and newaz, 1995. An illustrative example of design of a barge hull girder is provided to show the influence of incorporating the concept of damage tolerance in optimum marine structural design. Dotfaaar0515 fatigue crack growth database for damage. 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. Fatigue behavior and damage tolerant design of bonded. In the world of structural design, there are two main analytical techniques that are currently employed when attempting to predict the durability of components and systems. Damagetolerant design practice accounts for initial flaws already existing in a.
A key element is the development of a comprehensive programme of inspections to detect cracks before they can affect flight safety. Boeing composite airframe damage tolerance and service. Hail ball sizes and velocities based on statistical data. Revision b by defense technical information center. Affidavit i declare in lieu of oath that i wrote this thesis and performed the associated research myself, using.
A design concept which has become popular in mechanical engineering within the last 20 years is the damage tolerant design concept, which is based on safety of damage detection during scheduled. Designing a wind turbine blade using a damage tolerance philosophy and a structural health monitoring system, will permit the structure to. Ali fatemi university of toledo all rights reserved chapter 2fatigue design methods 3 fatigue design flow chart. The data of this handbook combines the old data that were previously presented. The handbook 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 cracking problems, in. Nasgro was originally developed at nasa johnson space center to perform fracture control analysis on nasa space systems. However, both durability and damage tolerance design methodologies must address the deleterious effects of changes in material properties and the initiation and growth of microstructural damage that may occur during the service lifetime of the vehicle. The air force now implements damage tolerant design through the recommended practices of the department of defense joint services specification guide, jssg2006 1998. 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. Air force to design, manufacture, and maintain systems that.
Both damage tolerant design and nondestructive inspection are essential for achieving structural integrity, yet these interrelated disciplines are generally studied independently and implemented by different individuals within an organization. Lin department of aeronautics and astronautics university of washington, box 352400 seattle, wa 981952400 november 10, 2004. This design approach takes advantage of the portion of service life a component can have with a growing fatigue crack. Development of reliabilitybased damage tolerant structural design methodology motivation and key issues. The primary purpose of this handbook document is to provide guidelines and stateoftheart analysis methods that should aid engineering personnel in complying with the intent. Worked examples and handson experience of solution methods and procedures in structural fatigue, damage tolerance problems and airworthiness issues in aircraft structures. Depending on the type of industry, one particular philosophy can be preferred over the other. 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. Application of damage tolerant design in mechanical engineering doctoral thesis miraj muhammad jan university of leoben, november 2008. Such a damage tolerant design methodology is proposed based on a multilevel and multigoal decision model. A unique presentation of two key elements of structural design.
In safelife design, products are intended to be removed from service at a specific design life safelife is particularly relevant to simple metal aircraft, where airframe components are subjected to alternating loads over the lifetime of the aircraft which makes them susceptible to metal fatigue. Damage tolerant design and condition monitoring of composite. Damagetolerant composite design principles for aircraft. Advanced durability and damage tolerance design and analysis methods for composite structures lessons learned from nasa technology development programs charles e. This is the first edition of a handbook to support the usaf airplane damage tolerance requirements contained in mila83444. Krieg4 michigan technological university, houghton, mi, 49931 evan j. Pdf safelife and damagetolerant design approaches for.
Durability and damage tolerance design and certification requirements are addressed. Shuart structures and materials competency mail stop 121 langley research center national aeronautics and space administration. Apr 16, 20 the damage tolerance approach to design has been employed by the aerospace industry for decades. In these applications, stringent requirements on weight, damage tolerance, reliability and cost must be satisfied. Damage tolerance is the ability to resist fracture from. The design methodology which takes these into account is the damage tolerant design approach dtd. Under these circumstances, a design that complies with the fatigue evaluation safelife requirements is used. Sample damage tolerance criteriaimpactsample damage tolerance criteriaimpact ultimate design strength, no moisture intrusion and no detrimental damage growth during dso for smaller size simulated hail ball. Pdf damage tolerant design of the aircraft components. 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. Damage tolerant composite design principles for aircraft. These systems are designed to work for years without requirement of any repairs. This edition is arranged by alloy rather than by property as in the previous addition.
Semantic scholar extracted view of safelife and damagetolerant design approaches for helicopter structures by harold k. Limit residual strength for larger size simulated hail. Modelingdriven damage tolerant design of graphene nanoplateletcarbon fiberepoxy hybrid composite panels for fullscale aerospace structures julie m. Introduction fracture mechanics fatigue crack propagation.
Advanced durability and damage tolerance design and analysis. Even though this particular problem could be partially mitigated by using the hourglass stiffness enhanced element formulation, the use of c3d8r elements in the numerical models was avoided for greater accuracy. Later, after the nasafaausaf aging aircraft program was formed and began supporting the development effort, nasgro was developed further for use in damage tolerance analysis of aircraft, including that required for faa certification. 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.
The data are presented in eight chapters and four volumes. Damage tolerant design for wind turbine blades designing a wind turbine blade using a damage tolerance philosophy and a structural health monitoring system, will permit the structure to operate despite the presence of damage, such as due to fatigue, intrinsicdiscrete damage, manufacturing defects, or severe accidental damage. A key element is the development of a comprehensive programme of inspections to detect cracks before they. 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 dtdh is a comprehensive compilation of fracture and crack growth data for high strength alloys. Optimum design of damage tolerant marine structures. Limit residual strength for larger size simulated hail ball. Ac 12093 damage tolerance inspections for repairs and. Its strength ranges from close to zero to almost full strength. Fatigue behavior and damage tolerant design of bonded joints for aerospace application on fmls and composites 3 weak bond is characterized by an adhesive failure mode between adherend and adhesive. The root cause is an insufficient adhesion of the adherend interfaces e. The damage tolerance approach to design has been employed by the aerospace industry for decades.
Dtdhandbook fundamentals of damage tolerance computer. Fatigue analysis of mechanical components, in many cases, leads to underestimated lives and thus greater costs, so a different philosophy was developed, damage tolerance design. The fracture toughness, crack growth, rcurve, sustained load and. Various fracture criteria and crack growth rules are studied. In contrast to the safe life design method, damage tolerance explicitly accounts the fatigue crack growth process. Air force to design, manufacture, and maintain systems that are structurally safe and economically prudent. The handbook is a compilation of mechanical property data that. Aircraft fatigue and damage tolerance cranfield university. Development of reliabilitybased damage tolerant structural design methodology presented to amtas autumn 2004 meeting by kuen y. In case of cyclic loading, the dtd approach ensures that the inherent cracks will not propagate to failure either within the design life or between inspection periods. Damagetolerant design an overview sciencedirect topics. Modeling driven damage tolerant design of graphene. This damage tolerance assessment handbook consists of two volumes.