EN 16603-32-01:2014

SLOVENSKI STANDARD
01-november-2014
1DGRPHãþD
SIST EN 14165:2004
Vesoljska tehnika - Kontrola razpok
Space engineering - Fracture control
Raumfahrttechnik - Überwachung des Rissfortschritts
Ingénierie spatiale - Maîtrise de la rupture
Ta slovenski standard je istoveten z: EN 16603-32-01:2014
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 16603-32-01
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2014
ICS 49.140 Supersedes EN 14165:2004
English version
Space engineering - Fracture control
Ingénierie spatiale - Maîtrise de la rupture Raumfahrttechnik - Überwachung des Rissfortschritts
This European Standard was approved by CEN on 10 February 2014.

CEN and CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving
this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning
such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN and CENELEC
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN and CENELEC member into its own language and notified to the CEN-CENELEC Management Centre
has the same status as the official versions.

CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia,
Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

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© 2014 CEN/CENELEC All rights of exploitation in any form and by any means reserved Ref. No. EN 16603-32-01:2014 E
worldwide for CEN national Members and for CENELEC
Members.
Table of contents
Foreword . 6
1 Scope . 7
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 10
3.1 Terms from other standards . 10
3.2 Terms specific to the present standard . 11
3.3 Abbreviated terms. 17
4 Principles . 19
5 Fracture control programme . 21
5.1 General . 21
5.2 Fracture control plan . 21
5.3 Reviews . 22
5.3.1 General . 22
5.3.2 Safety and project reviews . 23
6 Identification and evaluation of PFCI . 25
6.1 Identification of PFCIs . 25
6.2 Evaluation of PFCIs . 26
6.2.1 Damage tolerance . 26
6.2.2 Fracture critical item classification . 28
6.3 Compliance procedures . 28
6.3.1 General . 28
6.3.2 Safe life items . 28
6.3.3 Fail-safe items . 29
6.3.4 Contained items . 30
6.3.5 Low-risk fracture items . 31
6.4 Documentation requirements . 36
6.4.1 Fracture control plan . 36
6.4.2 Lists . 36
6.4.3 Analysis and test documents . 36
6.4.4 Fracture control summary report . 36
7 Fracture mechanics analysis . 38
7.1 General . 38
7.2 Analytical life prediction . 39
7.2.1 Identification of all load events . 39
7.2.2 Identification of the most critical location and orientation of the crack . 39
7.2.3 Derivation of stresses for the critical location. 40
7.2.4 Derivation of the stress spectrum . 40
7.2.5 Derivation of material data . 41
7.2.6 Identification of the initial crack size and shape . 41
7.2.7 Identification of an applicable stress intensity factor solution . 42
7.2.8 Performance of crack growth calculations . 43
7.3 Critical crack-size calculation . 43
8 Special requirements . 45
8.1 Introduction . 45
8.2 Pressurized hardware . 45
8.2.1 General . 45
8.2.2 Pressure vessels . 45
8.2.3 Pressurized structures . 48
8.2.4 Pressure components . 48
8.2.5 Low risk sealed containers . 49
8.2.6 Hazardous fluid containers . 49
8.3 Welds . 50
8.3.1 Nomenclature . 50
8.3.2 Safe life analysis of welds . 50
8.4 Composite, bonded and sandwich structures . 51
8.4.1 General . 51
8.4.2 Defect assessment. 51
8.4.3 Damage threat assessment . 53
8.4.4 Compliance procedures . 54
8.5 Non-metallic items other than composite, bonded, sandwich and glass items . 57
8.6 Rotating machinery . 58
8.7 Glass components . 58
8.8 Fasteners . 59
9 Material selection . 61
10 Quality assurance and Inspection . 62
10.1 Overview . 62
10.2 Nonconformances. 62
10.3 Inspection of PFCI . 62
10.3.1 General . 62
10.3.2 Inspection of raw material . 63
10.3.3 Inspection of safe life finished items . 64
10.4 Non-destructive inspection of metallic materials . 65
10.4.1 General . 65
10.4.2 NDI categories versus initial crack size . 65
10.4.3 Inspection procedure requirements for standard NDI . 69
10.5 NDI for composites, bonded and sandwich parts . 72
10.5.1 General . 72
10.5.2 Inspection requirements . 73
10.6 Traceability . 74
10.6.1 General . 74
10.6.2 Requirements . 75
10.7 Detected defects . 75
10.7.1 General . 75
10.7.2 Acceptability verification . 76
10.7.3 Improved probability of detection . 77
11 Reduced fracture control programme . 78
11.1 Applicability. 78
11.2 Requirements . 78
11.2.1 General . 78
11.2.2 Modifications . 78
Annex A (informative) The ESACRACK software package . 80
Annex B (informative) References . 81
Bibliography . 82

Figures
Figure 5-1: Identification of PFCI . 22
Figure 6-1: Fracture control evaluation procedures . 27
Figure 6-2: Safe life item evaluation procedure for metallic materials . 33
Figure 6-3: Safe life item evaluation procedure for composite, bonded and sandwich
items . 34
Figure 6-4: Evaluation procedure for fail-safe items . 35
Figure 8-1: Procedure for metallic pressure vessel and metallic liner evaluation . 47
Figure 10-1: Initial crack geometries for parts without holes . 71
Figure 10-2: Initial crack geometries for parts with holes . 72
Figure 10-3: Initial crack geometries for cylindrical parts . 72

Tables
Table 8-1: Factor on stress for sustained crack growth analysis of glass items . 59
Table 10-1: Initial crack size summary, standard NDI . 68

Foreword
This document (EN 16603-32-01:2014) has been prepared by Technical
Committee CEN/CLC/TC 5 “Space”, the secretariat of which is held by DIN.
This standard (EN 16603-32-01:2014) originates from ECSS-E-ST-32-01C Rev. 1.
This European Standard shall be given the status of a national standard, either
by publication of an identical text or by endorsement, at the latest by February
2015, and conflicting national standards shall be withdrawn at the latest by
February 2015.
Attention is drawn to the possibility that some of the elements of this document
may be the subject of patent rights. CEN [and/or CENELEC] shall not be held
responsible for identifying any or all such patent rights.
This document supersedes EN 14165:2004.
This document has been developed to cover specifically space systems and has
therefore precedence over any EN covering the same scope but with a wider
domain of applicability (e.g. : aerospace).
According to the CEN-CENELEC Internal Regulations, the national standards
organizations of the following countries are bound to implement this European
Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
Scope
This ECSS Engineering Standard specifies the fracture control requirements to
be imposed on space segments of space systems and their related GSE.
The fracture control programme is applicable for space systems and related
GSE when required by ECSS-Q-ST-40 or by the NASA document NST 1700.7,
incl. ISS addendum.
The requirements contained in this Standard, when implemented, also satisfy
the fracture control requirements applicable to the NASA STS and ISS as
specified in the NASA document NSTS 1700.7 (incl. the ISS Addendum).
The NASA nomenclature differs in some cases from that used by ECSS. When
STS/ISS-specific requirements and nomenclature are included, they are
identified as such.
This standard may be tailored for the specific characteristic and constrains of a
space project in conformance with ECSS-S-ST-00.

Normative references
The following normative documents contain provisions which, through
reference in this text, constitute provisions of this ECSS Standard. For dated
references, subsequent amendments to, or revision of any of these publications
do not apply, However, parties to agreements based on this ECSS Standard are
encouraged to investigate the possibility of applying the more recent editions of
the normative documents indicated below. For undated references, the latest
edition of the publication referred to applies.

EN reference Reference in text Title
EN 16601-00-01 ECSS-S-ST-00-01 ECSS system – Glossary of terms
EN 16603-32 ECSS-E-ST-32 Space engineering – Structural
EN 16603-32-02 ECSS-E-ST-32-02 Space engineering – Structural design and
verification of pressurized hardware
EN 16602-20 ECSS-Q-ST-20 Space product assurance – Quality assurance
EN 16602-40 ECSS-Q-ST-40 Space product assurance – Safety
EN 16602-70 ECSS-Q-ST-70 Space product assurance – Materials, mechanical
parts and processes
EN 16602-70-36 ECSS-Q-ST-70-36 Space product assurance – Material selection for
controlling stress-corrosion cracking
EN 16602-70-45 ECSS-Q-ST-70-45 Space product assurance – Mechanical testing of
metallic materials
ASTM E 164 Standard Practice for Ultrasonic Contact Examination
of Weldments
ASTM E 426 Standard Practice for Electromagnetic (Eddy-
Current) Examination of Seamless and Welded
Tubular Products, Austenitic Stainless Steel and
Similar Alloys
ASTM E 1417 Standard Practice for Liquid Penetrant Examination
ASTM E 1444 Standard Practice for Magnetic Particle Examination
ASTM E 1742 Standard Practice for Radiographic Examination
DOT/FAA/AR- Metallic Materials Properties Development and
MMPDS Standardization (MMPDS) (former MIL-HDBK-5)
EN 4179 Aerospace – Qualification and Authorization of
Personnel for Non-destructive Testing
EN reference Reference in text Title
EN ISO 6520-1 Welding and allied processes – Classification of
geometric imperfections in metallic materials – Part
1: Fusion welding
ISO 17659 Welding – Multilingual terms for welded joints with
illustrations
MIL-HDBK-6870 Inspection program requirements, nondestructive,
for aircraft and missile materials and parts
NAS-410 Nondestructive testing personnel qualification and
certification
NSTS 1700.7 Safety Policy and Requirements For Payloads Using
the Space Transportation System (STS)
NSTS 1700.7 ISS Safety Policy and Requirements For Payloads Using
Addendum the International Space Station
SAE AMS-STD-2154 Process for inspection, ultrasonic, wrought metals
SAE AMS 2644 Inspection Material, Penetrant
NSTS/ISS 13830 Payload Safety Review and Data Submittal
Requirements For Payloads Using the Space Shuttle
& International Space Station
Terms, definitions and abbreviated terms
3.1 Terms from other standards
For the purpose of this Standard, the terms and definitions from ECSS-ST-00-01
apply, in particular for the following terms:
customer
NOTE In this standard, the customer is considered to
represent the responsible fracture control or
safety authority.
For the purpose of this Standard, the following term and definition from ECSS-
E-ST-10-03 apply:
proof test
For the purpose of this Standard, the following terms and definitions from
ECSS-E-ST-32 apply:
flaw
NOTE The term defect is used as a synonymous.
maximum design pressure (MDP)
service life
For the purpose of this Standard, the following term and definition from ECSS-
E-ST-32-02 apply:
burst pressure
hazardous fluid container
leak before burst, LBB
pressure component
pressure vessel
pressurized structure
sealed container
special pressurized equipment
visual damage threshold, VDT
NOTE 1 For typical implementation of thin-walled
composite structure, the VDT is sometimes more
specifically defined as the impact energy of an
impactor with a hemi-spherical tip of 16 mm
diameter resulting in 0,3 mm or more remaining
surface deflection, after sufficiently long time to
cover potential evolution of the indentation over
time (due to e.g. wet ageing, fatigue loading,
viscoelasticity of the resin) between impact and
inspection.
NOTE 2 It can be time consuming to determine the VDT
based on remaining surface deflection of 0,3 mm
(see NOTE 1) after a sufficiently long time.
Therefore, tests which cause mechanical damage
corresponding to a deflection of at least 1 mm,
immediately after impact, are sometimes used to
determine the VDT.
For the purpose of this Standard, the following term and definition from ECSS-
Q-ST-40 apply:
catastrophic hazard
critical hazard
3.2 Terms specific to the present standard
3.2.1 aggressive environment
combination of liquid or gaseous media and temperature that alters static or
fatigue crack-growth characteristics from normal behaviour associated with an
ambient temperature and laboratory air environment
3.2.2 analytical life
life evaluated analytically by crack-growth analysis or fatigue analysis
3.2.3 catastrophic hazard
see ECSS-Q-ST-40B
3.2.4 catastrophic hazard
potential risk situation that can result in a
disabling or fatal personnel injury, loss of the NASA orbiter, ISS, ground
facilities, or STS/ISS equipment
[NSTS 1700.7 incl. ISS Addendum, paragraph 302]
3.2.5 close visual inspection
close proximity, intense visual examination of the internal and external surfaces
of a structure, including structural details or locations, for indications of impact
damage, flaws, and other surface defects
NOTE The inspection capability is evaluated by the
surface deflection measurement (impact depth).
The close visual inspection is considered to
detect reliably a deflection larger than the
visual damage threshold (VDT).
3.2.6 containment
damage tolerance design principle that, if a part fails, prevents the propagation
of failure effects beyond the container boundaries
NOTE 1 A contained part is not considered PFCI, unless its
release can cause a hazard inside the container.
The container is a PFCI, and its structural integrity
after impact is verified as part of fracture control
activities.
NOTE 2 In this standard, the term containment in most
cases also covers items which are e.g. restrained by
a tether to prevent the occurrence of hazardous
events due to failure of the item.
3.2.7 crack-like defect
defect that has the same mechanical behaviour as a crack
NOTE 1 “Crack” and “crack-like defect” are considered
synonymous in this standard.
NOTE 2 Crack-like defects can, for example, be initiated
during material production, fabrication or testing
or developed during the service life of a
component.
NOTE 3 The term “crack-like defect” can include:
• For metallic materials flaws, inclusions,
pores and other similar defects.
• For non-metallic materials, debonding,
broken fibres, delamination, impact damage
and other specific defects depending on the
material.
3.2.8 crack aspect ratio, a/c
ratio of crack depth to half crack length
3.2.9 crack aspect ratio, a/c
ratio of crack depth to crack length
3.2.10 crack growth rate
rate of change of crack dimension with respect to the number of load cycles or
time
NOTE For example da/dN, dc/dN, da/dt and dc/dt.
3.2.11 crack growth retardation
reduction of crack-growth rate due to overloading of the cracked structural
member
3.2.12 critical crack size
the crack size at which the structure fails under the maximum specified load
NOTE The maximum specified load is in many cases
the limit load, but sometimes higher than the
limit load (e.g. for detected defects, composites
and glass items)
3.2.13 critical initial defect, CID
critical (i.e., maximum) initial crack size for which the structure can survive the
specified number of lifetimes.
3.2.14 critical stress-intensity factor
value of the stress-intensity factor at the tip of a crack at which unstable
propagation of the crack occurs
NOTE 1 This value is also called the fracture toughness.
The parameter KIC is the fracture toughness for
plane strain and is an inherent property of the
material. For stress conditions other than plane
strain, the fracture toughness is denoted KC. In
fracture mechanics analyses, failure is assumed to
be imminent when the applied stress-intensity
factor is equal to or exceeds its critical value, i.e.
the fracture toughness. See 3.2.25.
NOTE 2 The term fracture toughness is used as a
synonymous.
3.2.15 cyclic loading
fluctuating load (or pressure) characterized by relative degrees of loading and
unloading of a structure
NOTE For example, loads due to transient responses,
vibro-acoustic excitation, flutter, pressure
cycling and oscillating or reciprocating
mechanical equipment.
3.2.16 damage tolerance threshold strain
maximum strain level below which damage
compatible with the sizes established by non-destructive inspection (NDI),
special visual inspection, the damage threat assessment, or the minimum sizes
6 8
imposed does not grow in 10 cycles (10 cycles for rotating hardware) at a load
ratio appropriate to the application
NOTE 1 Strain level is the maximum absolute value of
strain in a load cycle.
NOTE 2 The damage tolerance threshold strain is a
function of the material type and lay-up and is
determined from test data in the design
environment to the applicable or worst type and
orientation of strain and flaw for a particular
design and flaw size (e.g. the size determined by
the VDT).
3.2.17 damage tolerant
characteristic of a structure for which the amount of general degradation or the
size and distribution of local defects expected during operation, or both, do not
lead to structural degradation below specified performance
3.2.18 defect
see ‘flaw’ (3.1)
3.2.19 detected defect
defect known to exist in the hardware
3.2.20 fail-safe
damage-tolerance design principle, where a structure has
redundancy to ensure that failure of one structural element does not cause
general failure of the entire structure during the remaining lifetime
3.2.21 fastener
item that joins other structural items and transfers loads from one to the other
across a joint
3.2.22 fatigue
cumulative irreversible damage incurred by cyclic application of loads to
materials and structures
NOTE 1 Fatigue can initiate and extend cracks, which
degrade the strength of materials and structures.
NOTE 2 Examples of factors influencing fatigue behaviour
of the material are the environment, surface
condition and part dimensions
3.2.23 fracture critical item
item classified as such
3.2.24 fracture limited life item
hardware item that requires periodic re-inspection or replacement to be in
conformance with fracture control requirements
3.2.25 fracture toughness
materials’ resistance to the unstable propagation of a crack
NOTE See critical stress intensity factor, 3.2.14.
3.2.26 initial crack size
maximum crack size, as defined by non-destructive inspection, for performing a
fracture control evaluation
3.2.27 joint
element that connects other structural elements and transfers loads from one to
the other across a connection
3.2.28 load enhancement factor, LEF
factor to be applied on the load level of the spectrum of fatigue test(s) in order
to demonstrate with the test(s) a specified level of reliability and confidence
NOTE 1 The LEF is dependent upon the material or
construction, the number of test articles, and the
duration of the tests.
NOTE 2 MIL-HDBK-17F, Volume 3, Section 7.6.3 gives an
approach for calculating the LEF for composite
structures.
3.2.29 loading event
condition, phenomenon, environment or mission phase to which the structural
system is exposed and which induces loads in the structure
3.2.30 load spectrum
representation of the cumulative static and dynamic loadings anticipated for a
structural element during its service life
NOTE Load spectrum is also called load history.
3.2.31 mechanical damage
induced flaw in a composite hardware item that is caused by external
influences, such as surface abrasions, cuts, or impacts
3.2.32 potential fracture critical item, PFCI
item for which the initiation or propagation of cracks in structural items during
the service life can result in a catastrophic or critical hazard, or NASA STS/ISS
catastrophic hazardous consequences
NOTE Pressure vessels and rotating machinery are
always considered PFCI. See Figure 5-1.
3.2.33 R-ratio
ratio of the minimum stress to maximum stress
3.2.34 residual stress
stress that remains in the structure, owing to processing, fabrication, assembly
or prior loading
3.2.35 rotating machinery
rotating mechanical assembly that has a kinetic energy of 19300 joules or more,
or an angular momentum of 136 Nms or more
NOTE The amount of kinetic energy is based on 0,5 Iω
where I is the moment of inertia (kg.m ) and ω
is the angular velocity (rad/s).
3.2.36 safe life
fracture-control design principle, for which the largest undetected defect that
can exist in the part does not grow to failure when subjected to the cyclic and
sustained loads and environments encountered in the service life
3.2.37 special NDI
NDI methods that are capable of detecting cracks or crack-like flaws smaller
than those assumed detectable by Standard NDI or do not conform to the
requirements for Standard NDI
NOTE 1 See 10.4.2.1 and 10.4.3.
NOTE 2 Special NDI methods are not limited to fluorescent
penetrant, radiography, ultrasonic, eddy current,
and magnetic particle. See also 10.4.2.2.
3.2.38 standard NDI
NDI methods of metallic materials for which the required statistically based
flaw detection capability has been established. and it is listed in Table 10-1
NOTE 1 For standard NDI, see clauses 10.4.2.1 and 10.4.3.
NOTE 2 For required statistically based flaw detection
capability, see 10.4.2.1e.
NOTE 2 Limitations on the applicability of standard NDI to
radiographic NDI can be found in 10.4.2.1f and
10.4.2.1g.
NOTE 4 Standard NDI methods addressed by this
document are limited to fluorescent penetrant,
radiography, ultrasonic, eddy current, and
magnetic particle.
3.2.39 stress-corrosion cracking, SCC
initiation or propagation, or both, of cracks, owing to the combined action of
applied sustained stresses, material properties and aggressive environmental
effects
NOTE The maximum value of the stress-intensity
factor for a given material at which no
environmentally induced crack growth occurs
at sustained load for the specified environment
is KISCC.
3.2.40 stress intensity factor, K
calculated quantity that is used in fracture mechanics analyses as a measure of
the stress-field intensity near the tip of an idealised crack
NOTE Calculated for a specific crack size, applied
stress level and part geometry. See 3.2.14.
3.2.41 threshold stress intensity range, ∆K
th
stress-intensity range below which crack growth does not occur under cyclic
loading
3.2.42 variable amplitude spectrum
load spectrum or history whose amplitude varies with time
3.3 Abbreviated terms
For the purpose of this Standard, the abbreviated terms from ECSS-S-ST-00-01
and the following apply:
Abbreviation Meaning
crack aspect ratio (see 3.2.8)
a/c
acceptance review
AR
American Society of Mechanical Engineers
ASME
American Society for Testing and Materials
ASTM
British Standard
BS
critical design review
CDR
critical initial defect
CID
composite overwrapped pressure vessel
COPV
United States Department of Transportation
DOT
document requirements definition
DRD
European Standard
EN
elastic-plastic fracture mechanics
EPFM
European Space Agency
ESA
failure assessment diagram
FAD
fracture-critical item
FCI
fracture-critical items list
FCIL
finite element
FE
fracture-limited life item
FLLI
fracture-limited life items list
FLLIL
foreign object debris
FOD
design tensile yield strength (in MPa)
Fty
design tensile ultimate strength (in MPa)
Ftu
ground support equipment
GSE
International Organisation for Standardisation
ISO
International Space Station
ISS
resistance curve based on J-integral
J-R curve
resistance curve based on stress intensity factor (K)
K-R curve
leak before burst
LBB
load enhancement factor
LEF
linear elastic fracture mechanics
LEFM
fracture toughness for stress conditions other than plane
KC
strain
NOTE: See NOTE 1 of definition 3.2.14.
plane strain fracture toughness
KIC
threshold stress-intensity factor for stress-corrosion cracking
KISCC
threshold stress-intensity range
∆Kth
maximum design pressure
MDP
maximum expected operating pressure
MEOP
National Aeronautics and Space Administration
NASA
non-destructive inspection
NDI
non-hazardous leak before burst
NHLBB
National Space Transportation System (NASA Space Shuttle)
NSTS
preliminary design review
PDR
potential fracture-critical item
PFCI
potential fracture-critical items list
PFCIL
ratio of the minimum stress to maximum stress
R
reduced fracture-control programme
RFCP
Society of Automotive Engineers
SAE
stress-corrosion cracking
SCC
international system of units
SI
system requirements review
SRR
Space Transportation System (US Space Shuttle)
STS
ultrasonic
US
visual damage threshold
VDT
Principles
The following assumptions and prerequisites are the basis of the
implementation of the requirements contained in this standard. They can be
used as reference for example when alternative approaches, not directly
covered by the requirements of this standard, are assessed for equivalent safety
or reliability.
• All structural elements contain crack-like defects located in the most
critical area of the component 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 an upper
bound on the initial size of the cracks which result from these defects. For
conservatism, this crack size then becomes the smallest allowable size to
be used in any analysis or assessment.
• After undergoing a sufficient number of cycles at sufficiently high stress
amplitude, materials exhibit a tendency to propagate cracks, even in non-
aggressive environments.
• Whether, under cyclic or sustained tensile stress, a pre-existing (or load-
induced) crack does or does not propagate depends on:
 the material behaviour with crack;
 the initial size and geometry of the crack;
 the presence of an aggressive environment;
 the geometry of the item;
 the magnitude and number of loading cycles;
 the duration of sustained load;
 the temperature of the material.
• For metallic materials, the engineering discipline of linear elastic fracture
mechanics (LEFM) provides analytical tools for the prediction of crack
propagation and critical crack size. Validity of LEFM, depends on stress
level, crack configuration and structural geometry. The engineering
discipline of elastic-plastic fracture mechanics (EPFM) provides analytical
tools for the prediction of crack initiation, stable ductile crack growth and
critical crack size.
• For non-metallic materials (other than glass and other brittle materials)
and fibre-reinforced composites (both with metal and with polymer
matrix), linear elastic fracture mechanics technology is agreed by most
authorities to be inadequate, with the exception of interlaminar fracture
mechanics applied to debonding and delamination. Fracture control of
these materials relies on the techniques of safe life assessment supported
by tests, containment, fail safe assessment, and proof testing.
Composite, bonded and sandwich items are manufactured and verified
to high quality control standards to assure aerospace quality hardware.
The hardware developer of composite, bonded and sandwich items uses
only manufacturing processes and controls (NDI, coupon tests, sampling
techniques, etc.) that are demonstrated to be reliable and consistent with
established aerospace industry practices for composite/bonded
structures.
• The observed scatter in measured material properties and fracture
mechanics analysis uncertainties is considered.
NOTE For example, scatter factor and LEF
• For NSTS and ISS payloads, entities controlling the pressure are two-fault
tolerant, see NSTS 1700.7 (incl. ISS Addendum).
NOTE For example, regulators, relief devices and
thermal control systems
Fracture control programme
5.1 General
a. A fracture control programme shall be implemented by the supplier for
space systems and their related GSE in conformance with this Standard,
when required by ECSS-Q-ST-40 or the NASA document NSTS 1700.7,
incl. ISS Addendum (clause 208.1).
b. Fracture control requirements as defined in this standard shall be applied
where structural failure can result in a catastrophic or critical hazard.
NOTE In NASA NSTS 1700.7 (Safety Policy and
Requirements For Payloads Using the Space
Transportation System [STS]), incl. ISS
Addendum, the payload structural design is
based on fracture control procedures when the
failure of a structural item can result in a
catastrophic event.
c. Implementation of fracture control for structural GSE may be limited to
items which are not covered by other structural safety requirements.
NOTE In many cases this limits fracture control
verification to elements directly interfacing
with flight hardware.
d. Items for which implementation of fracture control programme is
required shall be selected in conformance with Figure 5-1.
e. For unmanned, single-mission, space vehicles and their payloads, and
GSE the reduced fracture control programme, specified in clause 11, may
be implemented.
5.2 Fracture control plan
a. The supplier shall prepare and implement a fracture control plan in
conformance with ECSS-E-ST-32 ‘Fracture control plan – DRD’.
b. The fracture control plan shall be subject to approval by the customer.
Legend
* contained or restrained items (see
subclause 6.3.4) are generally not
considered PFCI. Their containers are. Design concept
and
management
Manned or reusable
Unmanned, single mission
projects
projects or GSE*
Reduced fracture control per
clause 11
Structural screening Hazard analysis

For reduced fracture control identify items per subclause 11.2
No
Is item a pressure
Can failure lead to
No
vessel or rotat ing
catastrophic or
critical hazard ?* machinery ?

Yes
Yes
Fracture control required
Fracture control not
required
Record item as potential
fracture–critical item
Figure 5-1: Identification of PFCI
5.3 Reviews
5.3.1 General
a. Fracture control activities and status shall be reported during all project
reviews.
NOTE For project reviews, see ECSS-M-ST-10.
5.3.2 Safety and project reviews
a. The schedule of fracture control activities shall be related to, and support,
the project safety review schedule.
NOTE As specified in ECSS-Q-ST-40, safety reviews
are performed in parallel with major project
reviews.
b. Fracture control documentation shall be provided for the reviews as
follows:
1. For a system requirements review (SRR)
The results of preliminary hazard analysis and fracture control
screening (which follows the methodology given in Figure 5-1) and
a written statement as to whether or not fracture control is
applicable.
2. For a preliminary design review (PDR)
(a) A written statement which either confirms that fracture
control is required or else provides a justification for not
implementing fracture control.
(b) Identification of fracture control-related project activities in
the fracture control plan including:
− Definition of the scope of planned fracture control
activities dependent upon the results of the hazard-
analysis and fracture control screening performed.
− Identification of low-risk fracture items.
− Identification of primary design requirements and
constraints which are affected by or affecting fracture
control implementation.
NOTE For the fracture control plan, see 5.2.
(c) Submission of the fracture control plan to the customer for
approval.
(d) Lists of potential fracture critical items and fracture critical
items in conformance with clause 6.4.2.
3. For a critical design review (CDR)
(a) A final fracture control plan which is approved by the
customer.
(b) Verification requirements for inspection procedures and
personnel.
(c) The status of fracture control activities, together with a
specific schedule for completion of the verification activities.
(d) A description and summary of the results of pertinent
analyses and tests.
NOTE See clause 6.4.
(e) List of potential fracture critical items in conformance with
clause 6.4.2.
(f) List of fracture critical items in conformance with clause 6.4.2.
(g) List of fracture limited-life items in conformance with clause
6.4.2.
4. For an acceptance review (AR) or qualification review (QR)
(a) A fracture control summary report in conformance with
clause 6.4.4, showing completion of all frac
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