1、 JSC 25863B FRACTURE CONTROL PLAN FOR JSC SPACE-FLIGHT HARDWARE JSC Fracture Control Board April 2009 Approved for Public Release; Distribution is Unlimited National Aeronautics and Space Administration Lyndon B. Johnson Space Center Houston, Texas 1Provided by IHSNot for ResaleNo reproduction or ne
2、tworking permitted without license from IHS-,-,-JSC 25863, FRACTURE CONTROL PLAN FOR JSC SPACE-FLIGHT HARDWARE, REVISION B APRIL, 2009 2Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-DOCUMENT HISTORY LOG Status Document Revision Approval Date Descri
3、ption Baseline N/A May 1992 Fracture Control Plan for JSC Flight Hardware Revision A August 1998 Fracture Control Plan for JSC Flight Hardware Revision B April 2009 Fracture Control Plan for JSC Space-flight Hardware 3Provided by IHSNot for ResaleNo reproduction or networking permitted without licen
4、se from IHS-,-,-Index 1.0 Introduction 7 2.0 Purpose 8 3.0 Applicability 8 4.0 Responsibilities 9 4.1 Program/Project 9 4.2 JSC FCM 10 4.3 Fracture Control Milestones 10 4.4 JSC Fracture Control Board (FCB) 10 5.0 Applicable Documents 11 6.0 Fracture Control Classification of Parts 12 6.1 Non-Fractu
5、re-Critical Parts/Components 13 6.1.1 Low-Release Mass 13 6.1.2 Contained 14 6.1.3 Fail-Safe 14 6.1.4 NHLBB Pressurized Lines, Fittings and Components 16 6.1.5 Low-Energy Rotating Machineries 16 6.1.6 Fasteners and Shear Pins 17 6.1.7 Shatterable Components and Structures 18 6.1.7.1 Shatterable Comp
6、onents and Structures Inside Habitable Module 18 6.1.7.2 External Shatterable Components and Structures 18 6.1.8 Sealed Containers 18 6.1.9 Tools/Mechanisms 19 6.1.10 Batteries 19 6.1.11 Low-Risk Structural Parts 20 6.2 Fracture-Critical Parts/Components 21 6.2.1 Pressurized Systems (Pressure Vessel
7、s and Lines, Fittings Levels of Containment Guidelines For 54 Payloads Utilizing Hazardous/Toxic Materials) Appendix D (ES4-07-031; Fracture Control of Mechanisms) 58 6Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1.0 Introduction Any part or compo
8、nent whose individual structural failure would be a catastrophic event will be evaluated for Fracture Control. These parts will be treated with appropriate Fracture Control rigor to assure that a catastrophic failure is not caused by manufacturing and service-induced flaws, damage, or cracks existin
9、g in the materials of construction. This Fracture Control Plan (FCP) presents the JSC implementation methodology for compliance with Fracture Control requirements on all manned space-flight programs. Many projects may be relatively small and generation of an FCP for each individual project, as requi
10、red by applicable specifications, may be overly demanding of available resources. The project may accept this FCP or other FCP that is approved by the JSC Fracture Control Monitor (FCM). The NASA/JSC FCM may be contacted for assistance with programmatic implementation of Fracture Control. Experience
11、 has shown that relatively few parts or components will be truly “fracture-critical“. Some hardware will have no fracture-critical parts. Use of this plan will simplify classification of parts and systems. Designers and analysts are encouraged to develop a working familiarity with this FCP to minimi
12、ze Fracture Control implementation problems and/or costs. Terms defined in Appendix A of this document and in glossary sections of applicable requirements documents will be consulted for proper understanding and implementation of this FCP. A viable Fracture Control program relies on proper design an
13、d analysis and on high quality of parts/components in-flight structures and pressurized or mechanical systems. Design and quality requirements for critical-flight hardware are expected to be consistent with aerospace standards. It is beyond the scope, or intent, of this FCP to specify requirements o
14、f flight hardware that already exist. Fracture Control supplements well-designed, high-quality hardware with significant additional assurance against catastrophic failures resulting from unexpected and/or undetectable flaws. Fracture Control does not replace other applicable requirements for flights
15、 such as vibration testing, strength, structural life/fatigue, etc. Basic assumptions that underlie Fracture Control implementation include: (a) All individual structural parts contain flaws or crack-like defects. The minimum service life capability of the part may be determined by considering one a
16、nd only one flaw in the most critical area of the part and in the most unfavorable orientation. (b) The use of Non-Destructive Evaluation (NDE) techniques does not negate the above assumption. The NDE techniques establish a probable upper bound on the size of the assumed initial flaw at a specified
17、confidence level. (c) All space-flight hardware will be of good design, certified for the application, acceptance tested as required, and manufactured and assembled using high-quality processes. 7Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-There
18、are no differences between in-house and contracted efforts as to when Fracture Control is required. Fracture Control is not intended to compensate for poor design, analytical errors, misuse, or poor quality. Implementation of Fracture Control enhances the safety and mission reliability of the flight
19、 hardware by reducing the risk of catastrophic failure. Although Fracture Control can be effective in assuring mission success, it is not specifically required for that purpose and is up to the discretion of the Hardware Developer (HD) to use for that purpose. Fracture Control of the hardware will i
20、mplement the required rigor based on the hazard criticality evaluation and agreement. The FCM will verify that acceptable Fracture Control has been implemented on JSC flight hardware. The FCM does not normally determine the criticality of a structural failure on given hardware, but is available to b
21、oth the project and safety organizations for consultation in such determinations and does have the prerogative to question classifications. Since Fracture Control is implemented to assure safety, the FCM will respect the Safety and Mission Assurance (S General Fracture Control Requirements for Manne
22、d Spaceflight Systems NASA-STD-5019; Fracture Control Requirements for Spaceflight Hardware NASA-STD-5003; Fracture Control Requirements for Payloads Using the Space Shuttle SSP 30558C; Fracture Control Requirements for Space Station SSP 52005C; Payload Flight Equipment Requirements and Guidelines f
23、or Safety-Critical Structures NASA-HDBK-5010; Fracture Control Implementation Handbook for Payloads, Experiments, and Similar Hardware NASGRO; Fracture Mechanics and Fatigue Crack Growth Analysis Software Reference Manual, www.nasgro.swri.org NASA-STD-5009; Non Destructive Evaluation Requirements fo
24、r Fracture-Critical Metallic Components NASA-STD-6008; NASA Fastener Management and Control Practices NASA-STD-6016; Standard Materials and Processes Requirements for Spacecraft JSC 20793, Crewed Space Vehicle Battery Safety Requirements NSTS 1700.7B; Safety Policy and Requirements for Payloads Usin
25、g the Space Transportation System 11Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NSTS 1700.7B, ISS ADDENDUM; Safety Policy and Requirements for Payloads Using the International Space Station JSC 62550; Strength Design and Verification Criteria for
26、 Glass, Ceramics and Windows in Human Space Flight Applications DoT Title 49, United States Government Code, Department of Transportation ANSI/AIAA S-080-1998; Space Systems - Metallic Pressure Vessels, Pressurized Structures, and Pressure Components ANSI/AIAA S-081A-2006; Space Systems - Composite
27、Overwrapped Pressure Vessels (COPVs) API-RP 579-1; Fitness For Service, Section 9 ASME Boiler and Pressure Vessel Code, Section VIII, Division 1 or 2, September 2004; Rules for Construction of Pressure Vessels, Section VIII, Division 1 or Division 2, Alternative Rules ES4-02-050; Levels of Containme
28、nt Guidelines For Payloads Utilizing Hazardous/Toxic Materials ES4-07-031; Fracture Control of Mechanisms 6.0 Fracture Control Classification of Parts Where feasible, Fracture Control will be initiated by a structure/system screening for potential fracture-critical parts/components, based on structu
29、ral failure modes, consequence of failure, applicable requirements, and experience. The list of potential fracture-critical parts will serve as a contributing base for establishing the necessary Fracture Control rigor in the program according to the methodology in this FCP. Hardware may be classifie
30、d as: (a) Exempt, or (b) Non-fracture-critical, or (c) Fracture-critical. Exempt hardware typically includes items such as insulation blankets, switches, sensors, enclosed electrical circuit components/boards, electrical connectors, pins, tangs, lock wire, etc. used for fastener back-off prevention,
31、 wire bundles, seals, etc. Non-fracture-critical hardware generally includes the classifications of low-released mass, contained, fail-safe, non-hazardous leak-before-burst (NHLBB) pressurized lines, fittings & components, low-speed/low-energy and low-momentum rotating machineries, low-strain compos
32、ite parts, low-risk parts and fasteners, and protected glasses. Section 6.1 gives a 12Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-detailed explanation of each of these classifications and suggestions for classifying specific hardware items. Fract
33、ure-critical hardware includes pressure vessels, high-energy or high-momentum rotating equipments, hazardous material containers, habitable modules, solid rocket motor cases and propellant tanks and any remaining hardware that do not fit the first two categories of exempt or non-fracture-critical. A
34、ll fracture-critical hardware will be shown to meet damage-tolerant requirements through analysis or test or fleet-leader testing. Section 6.2 provides criteria for classifying and assessing specific types of fracture-critical hardware. The assessment of hardware criticality will examine the differe
35、nt phases of application including launch, on-orbit, and return-to-ground (including a contingency abort without ground services) to determine the applicability and extent of Fracture Control. For example, a part may not be fracture-critical during the launch phase, but could be fracture-critical fo
36、r on-orbit service. In this case Fracture Control assessments will address the on-orbit phase as well as potential effects of other phases on the on-orbit performance. Fracture-critical parts will be identified as such on the drawings. This alerts all who use the drawing as to the criticality of the
37、 part. Designers and analysts will work together to assure that required notations, including NDE and/or proof-test requirements, etc., are provided on the drawing for any fracture-critical part. 6.1 Non-Fracture-Critical Parts/Components If the structural failure of a part/component is clearly not
38、a catastrophic hazard, no further Fracture Control assessment is required. If the hazard is unclear, it could be classified as non-fracture-critical if it can be shown to meet one of the following categories addressed in Section 6.1.1 thru Section 6.1.11. These parts will be processed under conventi
39、onal aerospace verifications and quality assurance procedures. 6.1.1 Low-Released Mass Potential mass releases as a result of a single-point structural failure will be examined for hazard potential. Any part of any size in this category whose release would not be a catastrophic hazard either to the
40、source of the mass or to any other structures, systems, or crew that could be impacted by the mass during any phase of launch/reentry or flight can be classified non-fracture-critical. A released mass may either be internal or external to the spacecraft. The released mass inside the habitable module
41、 will not be able to achieve (for example, via contact with crew or release during launch) a velocity of more than 10.7 m/sec (35 ft/sec) or a momentum of more than 1.24 kg-m/sec (8.75 ft-lb/sec). Fasteners pre-loaded in tension which have a low-fracture toughness, KIc/Fty1240 MPa (180 ksi). Parts/c
42、omponents whose single-point failure would exceed low-released mass limits would, preferably, be shown to be contained (Section 6.1.2), or meet the low-risk criteria (Section 6.1.11) and, therefore, be classified as non-fracture-critical. Otherwise, applicable requirements of fracture-critical parts
43、 must be applied. 6.1.2 Contained A part confined in a container or housing, or otherwise positively restrained from free release, and whose failure would not result in a catastrophic event, can be classified non-fracture-critical. Pressurized components and rotating devices within stowed or contain
44、ed hardware will be assessed independently, as delineated in this FCP, to assure against explosion and/or release of fragments, hazardous fluids, over-pressurization and catastrophic failure of the container/compartment. Containment of rotating devices will consider the combined effect of rotational
45、 speed and potential for mass release to determine classification. Guidance for calculating containment of high-energy rotating devices is given in Appendix B of NASA-HDBK-5010. Hardware not in lockers/containers but having internal parts will be assessed on their individual merit for containment of
46、 loose internal parts. Enclosures with openings will be assessed for containment of parts larger than accessible openings. Engineering judgment supported by documented technical rationale may be used when it is obvious that an enclosure, a barrier, or a restraint exists that prevents the part from e
47、scaping. Typical electronic boxes and related equipment such as radios, cameras, recorders, personal computers, and similar close-packed and enclosed hardware can be regarded as acceptable containers of internal parts without further assessment. Release of a free mass from a fastener that is safety-wired will be assumed non-credible. All safety wired fasteners can be classified non-fracture-critical if failure does not result in a catastrophic event due to loss of structural integrity of the fastener. When containment is furnished by a compartment with doors or other open
