Space engineering standards - Fracture control

This standard specifies the fracture control requirements to be imposed on space systems.
The requirements contained in this standard, when implemented, also satisfy the requirements applicable to the NASA STS and ISS as defined in the NASA document NSTS 1700.7 (incl. the ISS Addendum). Since this standard and the NASA document NSTS 1700.7 (incl. the ISS Addendum) are subject to different independent approval authorities, and recognizing that possible changes to documents may occur in the future, the user of this standard is advised to confirm the current status.
NOTE  The definitions used in this standard are based on ECSS nomenclature and are given in clause 3. The NASA nomenclature differs in some cases from that used by ECSS. When STS-specific requirements and nomenclature are included, they are identified as such.

Raumfahrttechnik - Überwachung des Rissfortschritts

Ingénierie Spatiale - Maîtrise de la rupture

Standardi v vesoljski tehniki – Kontrola razpok

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EN 14165:2004
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Standardi v vesoljski tehniki – Kontrola razpokRaumfahrttechnik - Überwachung des RissfortschrittsIngénierie Spatiale - Maîtrise de la ruptureSpace engineering standards - Fracture control49.140Vesoljski sistemi in operacijeSpace systems and operationsICS:Ta slovenski standard je istoveten z:EN 14165:2004SIST EN 14165:2004en01-september-2004SIST EN 14165:2004SLOVENSKI

SIST EN 14165:2004

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 14165April 2004ICS 49.140English versionSpace engineering standards - Fracture controlIngénierie Spatiale - Maîtrise de la ruptureRaumfahrttechnik - Überwachung des RissfortschrittsThis European Standard was approved by CEN on 27 February 2004.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2004 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14165:2004: ESIST EN 14165:2004

EN 14165:2004 (E)2ContentsForeword.41Scope.52Normative references.53Terms, definitions and abbreviated terms.63.1Terms and definitions.63.2Abbreviated terms.104General requirements.115Fracture control programme.125.1General.125.2Responsibilities of supplier.125.3Fracture control plan.125.4Reviews.145.4.1General.145.4.2Safety reviews.146Identification and evaluation of PFCIs.156.1Identification of PFCIs.156.2Evaluation of PFCIs.156.2.1General.156.2.2Selection of the relevant locations on a PFCI.166.2.3Damage­ tolerant design.166.2.4Classification.176.3Compliance procedures.176.3.1Safe life items.176.3.2Fail safe items.176.3.3Contained items.176.4Documentation requirements.176.4.1Analysis and test documents.207Fracture mechanics analysis.217.1General.217.2Analysis.217.2.1Analytical life prediction.217.2.2Critical crack-size calculation.238Special requirements.238.1Pressurized systems.238.1.1General.238.1.2Pressure vessels.238.1.3Pressure lines, fittings and components.268.1.4Sealed containers.26SIST EN 14165:2004

EN 14165:2004 (E)38.2Welds.268.3Composites.278.4Rotating machinery.278.5Glass.278.6Fasteners.289Material selection general requirements.2810Quality assurance requirements.2810.1General.2810.2Nonconformances.2910.3Non­destructive inspection.2910.3.1General.2910.3.2NDI categories versus initial crack size.2910.4Inspection requirements.3310.5Traceability.3310.5.1General.3310.5.2Requirements.3311Reduced fracture control programme.3411.1General.3411.2Requirements.34 FiguresFigure 1 — Fracture control applicability.13Figure 2 — Fracture control procedures.16Figure 3 — Safe life item evaluation procedure.18 Figure 4 — Evaluation procedure for fail safe items.19Figure 5 — Logic for pressure vessel evaluation.25Figure 6 — Initial crack geometries for parts without holes.32Figure 7 — Initial crack geometries for parts with holes.32 TablesTable 1 — Initial crack size summary, standard NDI.30Table 2 — Initial crack summary, standard NDI for welds and castings.31SIST EN 14165:2004

EN 14165:2004 (E)4ForewordThis document (EN 14165:2004) has been prepared by CEN/CS.This European Standard shall be given the status of a national standard, either by publication of anidentical text or by endorsement, at the latest by October 2004, and conflicting national standards shallbe withdrawn at the latest by October 2004.It is based on a previous version1) originally prepared by the ECSS Engineering Working Group,reviewed by the ECSS Technical Panel and approved by the ECSS Steering Board. The EuropeanCooperation for Space Standardization (ECSS) is a cooperative effort of the European Space Agency,National Space Agencies and European industry associations for the purpose of developing andmaintaining common standards.This standard is one of the series of space standards intended to be applied together for themanagement, engineering and product assurance in space projects and applications.Requirements in this standard are defined in terms of what shall be accomplished, rather than in termsof how to organize and perform the necessary work. This allows existing organizational structures andmethods to be applied where they are effective, and for the structures and methods to evolve asnecessary without rewriting the standards.This European Standard specifies the fracture control requirements to be imposed in spaceprogrammes.The formulation of this standard takes into account the existing ISO 9000 family of documents.According to the CEN/CENELEC Internal Regulations, the national standards organizations of thefollowing countries are bound to implement this European Standard: Austria, Belgium, Cyprus, CzechRepublic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain,Sweden, Switzerland and United Kingdom.
1) ECSS-E-30-01A.SIST EN 14165:2004

EN 14165:2004 (E)51ScopeThis standard specifies the fracture control requirements to be imposed on space systems.The requirements contained in this standard, when implemented, also satisfy the requirementsapplicable to the NASA STS and ISS as defined in the NASA document NSTS 1700.7 (incl. the ISSAddendum). Since this standard and the NASA document NSTS 1700.7 (incl. the ISS Addendum) aresubject to different independent approval authorities, and recognizing that possible changes todocuments may occur in the future, the user of this standard is advised to confirm the current status.NOTE
The definitions used in this standard are based on ECSS nomenclature and are given in clause 3.The NASA nomenclature differs in some cases from that used by ECSS. When STS-specific requirementsand nomenclature are included, they are identified as such.2Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications.These normative references are cited at the appropriate places in the text and the publications are listedhereafter. For dated references, subsequent amendments to or revisions of any of these apply to thisEuropean Standard only when incorporated in it by amendment or revision. For undated references thelatest edition of the publication referred to applies (including amendments).EN 13291-2:2003, Space product assurance — General requirements — Part 2: Quality assurance.EN 13291-3:2003, Space product assurance — General requirements — Part 3: Materials, mechanicalparts and processes.EN 13701:2001, Space systems — Glossary of terms.EN 14097, Space product assurance — Nonconformance control system.EN 14101:2001, Space product assurance — Material selection for controlling stress­corrosion cracking.EN ISO 14620-1, Space systems - Safety requirements - Part 1: System safety (ISO 14620-1:2002).NAS410, Certification and qualification of non-destructive test personnel.MIL-STD-1522A, Standard general requirements for safe design and operation of pressurized missileand space systems.MIL-I-6870, Inspection program requirements, nondestructive, for aircraft and missile materials andparts.MSFC-STD-1249, Standard NDE guidelines and requirements for fracture control programs.NSTS/ISS 13830, Implementation Procedure for NSTS Payload System Safety Requirements.NSTS 1700.7, Safety Policy and Requirements For Payloads Using the Space Transportation System(STS).SIST EN 14165:2004

EN 14165:2004 (E)63Terms, definitions and abbreviated terms3.1Terms and definitionsFor the purposes of this European Standard, the terms and definitions given in EN 13701:2001, EN13291-3:2003 and the following apply.3.1.1aggressive environmentany combination of liquid or gaseous media and temperature that alters static or fatigue crack-growthcharacteristics from "normal" behaviour associated with an ambient temperature and laboratory airenvironment3.1.2allowable loadload that induces the allowable stress in a material3.1.3allowable stressmaximum stress tolerated in a material for a given operating environment to prevent rupture, collapse,detrimental deformation or unacceptable crack growth3.1.4analytical lifelife evaluated analytically, i.e. by crack-growth analysis or fatigue analysis3.1.5burst pressurepressure at which a pressurized system ruptures or collapses3.1.6catastrophic hazardpotential risk situation that can result in loss of life, in life­threatening or permanently disabling injury, inoccupational illness, loss of an element of an interfacing manned flight system, loss of launch sitefacilities or long term detrimental environmental effectsNOTE
For payloads of the NASA STS or ISS, the applicable definition is: "A potential risk situation that canresult in personnel injury, loss of the NASA orbiter, ground facilities, or STS equipment (see NSTS 1700.7,paragraph 302)".3.1.7containmenttechnique that, if a part fails, prevents the propagation of failure effects beyond the container boundaries3.1.8crack or crack-like defectdefect that behaves like a crack that is initiated, for example, during material production, fabrication ortesting or developped during the service life of a componentNOTE
The term "crack" in this definition includes flaws, inclusions, pores and other similar defects.3.1.9crack aspect ratiofor a part-through crack, the ratio of crack depth (a) to half crack length (c), i.e. a/c3.1.10crack growth rate (da/dN, dc/dN, da/dt or dc/dt)rate of change of depth a or length c with respect to the number of load cycles N or time tSIST EN 14165:2004

EN 14165:2004 (E)73.1.11crack growth retardationreduction of crack-growth rate due to intermittent overloading of the cracked structural member3.1.12critical hazardpotential risk situation that can result in:temporarily disabling but not life-threatening injury, or temporary occupational illness;loss of, or major damage to, flight systems, major flight system elements or ground facilities;loss of, or major damage to, public or private property; or short-term detrimental environmentaleffects3.1.13critical stress-intensity factor (fracture toughness)value of the stress-intensity factor at the tip of a crack at which unstable propagation of the crack occursNOTE
This value is also called the fracture toughness. The parameter KIC is the fracture toughness forplane strain and is an inherent property of the material. For stress conditions other than plane strain, thefracture toughness is denoted KC. In fracture mechanics analyses, failure is assumed to be imminent whenthe applied stress-intensity factor is equal to or exceeds its critical value, i.e. the fracture toughness. See3. loadingfluctuating load (or pressure) characterized by relative degrees of loading and unloading of a structureNOTE
Examples are loads due to transient responses, vibro-acoustic excitation, flutter and oscillating orreciprocating mechanical equipment.3.1.15damage-tolerantattribute of a structure if the amount of general degradation or the size and distribution of local defectsexpected during operation do not lead to structural degradation below limit-specified performance3.1.16fail safe (structure)damage-tolerance acceptability category in which the structure is designed with sufficient redundancy toensure that the failure of one structural element does not cause general failure of the entire structure3.1.17failure (structural)rupture, collapse, seizure, excessive wear or any other phenomenon resulting in an inability to sustainlimit loads, pressures and environments3.1.18fastenerany item that joins other structural items and transfers loads from one to the other across a joint(see 3.1.23)3.1.19fatiguecumulative irreversible damage in materials and structures incurred by cyclic application of loads ingiven environmentsNOTE
Fatigue can initiate and extend cracks, which degrade the strength of materials and structures.SIST EN 14165:2004

EN 14165:2004 (E)83.1.20fracture limited life itemany item that requires periodic reinspection to conform to safe life (see 3.1.37) or fail safe (see 3.1.16)requirements3.1.21fracture toughnesssee crack sizemaximum crack size, as defined by non-destructive inspection, that is assumed to exist for the purposeof performing a fracture mechanics evaluation3.1.23jointany element that connects other structural elements and transfers loads from one to the other across aconnection3.1.24KICplane strain fracture toughness (see critical stress intensity factor)3.1.25KISCCthreshold stress-intensity factor for stress corrosion cracking: the maximum value of the stress-intensityfactor for a given material at which no environmentally induced crack growth occurs at sustained load forthe specified environment3.1.26Kththreshold stress-intensity factor for dynamic loading: the stress-intensity range below which crack growthwill not occur under cyclic loading3.1.27leak before burstfracture mechanics design concept in which it is shown that any initial defect grows through the wall of apressurized system and cause leakage prior to burst (catastrophic failure) at maximum design pressure(see 3.1.31)3.1.28limit load or stressmaximum load or stress assumed to act on a structure in the expected operating environments3.1.29loading eventcondition, phenomenon, environment or mission phase to which the payload is exposed and whichinduces loads in the payload structure3.1.30load spectrum (history)representation of the cumulative static and dynamic loadings anticipated for a structural element duringits service life3.1.31maximum design pressure (MDP)highest possible pressure for a pressurized system occurring from maximum relief pressure, maximumregulator pressure, maximum temperature or transient pressure excursionsNOTE
Factors of safety apply to MDP.SIST EN 14165:2004

EN 14165:2004 (E)93.1.32payloadany equipment or material carried by the launcher that is not considered part of the basic launcher itselfNOTE
Payload includes items such as free-flying automated spacecraft, individual experiments andinstruments.3.1.33proof testtest of a flight structure at a proof load or pressure that gives evidence of satisfactory workmanship andmaterial quality or establishes the initial crack sizes in the structure3.1.34Rratio of the minimum stress to maximum stress3.1.35residual stressstress that remains in the structure, owing to processing, fabrication or prior loading3.1.36rotating machineryany rotating mechanical assembly that has a kinetic energy of 19 300 J or moreNOTE
The amount being based on 0,5 Iw2 where I is the moment of inertia (kg/m2) and w is the angularvelocity (rad/s).3.1.37safe lifea fracture-control acceptability category which requires that the largest undetected crack that can exist inthe part does not grow to failure when subjected to the cyclic and sustained loads and environmentsencountered in the service life3.1.38service lifeinterval beginning with an item’s inspection after manufacture and ending with completion of its specifiedlife3.1.39static load (stress)load (stress) of constant magnitude and direction with respect to the structure3.1.40stress corrosion cracking (SCC)initiation or propagation of cracks, owing to the combined action of applied sustained stresses, materialproperties and aggressive environmental effects3.1.41stress intensity factor (K)calculated quantity that is used in fracture mechanics analyses as a measure of the stress-field intensitynear the tip of an idealized crack, calculated for a specific crack size, applied stress level and partgeometry (see 3.1.13)3.1.42thermal load (stress)structural load (or stress) arising from temperature gradients and differential thermal expansion betweenstructural elements, assemblies, subassemblies or itemsSIST EN 14165:2004

EN 14165:2004 (E)103.1.43ultimate strengthstrength corresponding to the maximum load or stress that an unflawed structure or material canwithstand without incurring rupture or collapse3.1.44variable amplitude spectrumload spectrum or history whose amplitude varies with time3.1.45yield strengthstrength corresponding to the maximum load or stress that an unflawed structure or material canwithstand without incurring permanent deformation3.2Abbreviated termsThe following abbreviated terms are defined and used within this European Standard.AbbreviationMeaningARacceptance reviewASMEAmerican Society of Mechanical EngineersCDRcritical design reviewDOTUnited States Department of TransportationDRDdocument requirements definitionEFCBESA fracture control boardESAEuropean Space AgencyFCIfracture critical itemFCILfracture critical item listFLLIfracture limited life itemFLLILfracture limited life items listGSEground support equipmentISSinternational space stationLBBleak before burstMDPmaximum design pressureMEOPmaximum expected operating pressureNASANational Aeronautics and Space AdministrationNDInon-destructive inspectionNDEnon-destructive evaluationNSTSNational Space Transportation System (NASA Space Shuttle)PDRpreliminary design reviewSIST EN 14165:2004

EN 14165:2004 (E)11PFCIpotential fracture critical itemPFCILpotential fracture critical item listRthe ratio of the minimum stress to maximum stressRFCPreduced fracture-control programmeSCCstress corrosion crackingSIthe international system of units published by the international standardsorganisationSRRsystem requirements reviewSTSSpace Transportation System (US Space Shuttle)4General requirementsFracture control principles shall be applied where structural failure can result in a catastrophic or criticalhazard. The terms "catastrophic hazard" and "critical hazard" are defined in 3.1 of this standard.NOTE
In NASA NSTS 1700.7 (Safety Policy and Requirements For Payloads Using the SpaceTransportation System [STS]), the payload structural design is based on fracture control procedures whenthe failure of a STS payload structural item can result in a NASA STS payload catastrophic event.For the implementation of this standard the SI-units and associated symbols system shall be used.The assumptions and prerequisites which are the basis of the requirements contained in this standardare the following:a.All real structural elements contain crack-like defects located in the most critical area of thecomponent in the most unfavourable orientation. The inability of non-destructive inspection (NDI)techniques to detect such defects does not negate this assumption, but merely establishes anupper bound on the initial size of the cracks which result from these defects. For conservatism, thiscrack size then becomes the smallest allowable size to be used in any analysis or assessment.b.After undergoing a sufficient number of cycles at a sufficiently high stress amplitude, materialsexhibit a tendency to initiate fatigue cracks, even in non-aggressive environments.c.Whether, under cyclic or sustained tensile stress, a pre-existing (or load-induced) crack does ordoes not propagate depends on:·fracture toughness of the material;·initial size and geometry of the crack;·presence of an aggressive environment;·geometry of the item;·magnitude and number of loading cycles;·temperature of the material.d.The engineering discipline of linear elastic fracture mechanics provides analytical tools for theprediction of crack propagation and critical crack size.SIST EN 14165:2004

EN 14165:2004 (E)12e.For non-metallic materials (other than glass and glass-like materials) and fibre-reinforcedcomposites (both with metal and with polymer matrix), linear elastic fracture mechanics technologyis agreed by most authorities to be inadequate. Fracture control of these materials relies on thetechniques of containment, fail safe assessment, proof testing and cyclic load testing.f.A scatter factor is required to account for the observed scatter in measured material properties andfracture mechanics analysis uncertainties.g.For NSTS and ISS payloads, entities like regulators, relief devices and thermal control systemscontrolling the pressure, shall be two-fault tolerant, see NSTS 1700.7.5Fracture control programme5.1Generala.A fracture control programme shall be implemented (when required by EN ISO 14620-1 or theNASA document NSTS 1700.7, incl. ISS Addendum for space systems and their related GSE) inaccordance with this standard.A fracture control programme shall require that design be based on fracture control principles andprocedures when the initiation or propagation of cracks in structural items during the service life canresult in a catastrophic or critical hazard, or NASA STS catastrophic hazardous consequences, orwhen the structural item is a pressure vessel or is rotating machinery (see Figure 1).b.For unmanned, single-mission, space vehicles and their payloads, the reduced fracture controlprogramme, specified in clause 11, may be implemented.5.2Responsibilities of supplierThe equipment supplier shall be responsible for the implementation of the fracture control programmerequired by this standard.5.3Fracture control plana.The supplier shall prepare and implement a fracture control plan which conforms to therequirements of this standard. The fracture control plan, which shall be subject to approval by thecustomer, shall define the fracture control programme that shall be implemented and shall showhow the supplier performs and verifies the satisfactory completion of each of the activities in thefracture control programme.b.In the fracture control plan, each fracture control activity shall be identified and defined, the methodof implementation summarized, and the implementation schedule specified against projectmilestones. All applicable requirements and procedures shall be identified.SIST EN 14165:2004

EN 14165:2004 (E)13Figure 1 — Fracture control applicabilityYesDesign conceptandmanagementManned or reusableprojectsUnmanned, single missionprojectsReduced fracture control perclause 11Structural screeningHazard analysisFor reduced fracture control identify items per subclause 11.2Fracture control requiredFracture control

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