1、Designation: E 2581 07Standard Practice forShearography of Polymer Matrix Composites, SandwichCore Materials and Filament-Wound Pressure Vessels inAerospace Applications1This standard is issued under the fixed designation E 2581; the number immediately following the designation indicates the year of
2、original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes procedures for shearography ofpoly
3、mer matrix composites, sandwich core materials, andfilament-wound pressure vessels made entirely or in part fromfiber-reinforced polymer matrix composites. The compositematerials under consideration typically contain continuoushigh modulus (greater than 20 GPa (33106 psi) fibers, butmay also contain
4、 discontinuous fiber, fabric, or particulatereinforcement.1.2 This practice describes established shearography proce-dures that are currently used by industry and federal agenciesthat have demonstrated utility in quality assurance of polymermatrix composites, sandwich core materials, and filament-wo
5、und pressure vessels during product process design andoptimization, manufacturing process control, post manufactureinspection, and in service inspection.1.3 This practice has utility for testing of polymer matrixcomposites, sandwich core materials, and filament-woundpressure vessels containing but n
6、ot limited to bismaleimide,epoxy, phenolic, poly(amideimide), polybenzimidazole, poly-ester (thermosetting and thermoplastic), poly(ether ether ke-tone), poly(ether imide), polyimide (thermosetting and thermo-plastic), poly(phenylene sulfide), or polysulfone matrices; andalumina, aramid, boron, carb
7、on, glass, quartz, or siliconcarbide fibers. Typical as-fabricated geometries includeuniaxial, cross ply and angle ply laminates; as well as honey-comb and foam core sandwich materials and structures.1.4 This practice does not specify accept-reject criteria andis not intended to be used as a means f
8、or approving polymermatrix composites, sandwich core materials, or filament-wound pressure vessels for service. (Please note that a flawdoes not become a defect until rejected by acceptance/rejectioncriteria.)1.5 To ensure proper use of the referenced standards, thereare recognized nondestructive te
9、sting (NDT) specialists thatare certified in accordance with industry and company NDTspecifications. It is recommended that an NDT specialist be apart of any composite component design, quality assurance, inservice maintenance, or damage examination activity.1.6 This standard does not purport to add
10、ress all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 274 Termino
11、logy of Structural Sandwich ConstructionsD 3878 Terminology for Composite MaterialsD 5687/D 5687M Guide for Preparation of Flat CompositePanels with Processing Guidelines for Specimen Prepara-tionE 543 Specification for Agencies Performing Nondestruc-tive TestingE 1309 Guide for Identification of Fi
12、ber-ReinforcedPolymer-Matrix Composite Materials in DatabasesE 1316 Terminology for Nondestructive ExaminationsE 1434 Guide for Recording Mechanical Test Data of Fiber-Reinforced Composite Materials in DatabasesE 1471 Guide for Identification of Fibers, Fillers, and CoreMaterials in Computerized Mat
13、erial Property DatabasesE 1736 Practice for Acousto-Ultrasonic Assessment ofFilament-Wound Pressure Vessels2.2 Federal Standards:321 CFR 1040.10 Laser products21 CFR 1040.11 Specific purpose laser products29 CFR 1910.95 Occupational Noise Exposure2.3 ANSI Standard:41This practice is under the jurisd
14、iction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.10 onEmerging NDT Methods.Current edition approved Sept. 1, 2007. Published October 2007.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service
15、at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from U.S. Government Printing Office Superintendent of Documents,732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http:/www.access.gpo.gov.
16、4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Z136.1-2000 Safe Use of Lasers2.4 ASNT Standards:5SNT-TC-1
17、A Recommended Practice for Personnel Qualifi-cation and Certification in Nondestructive TestingANSI/ASNT CP-189 Standard for Qualification and Certi-fication of Nondestructive Testing Personnel2.5 AIA Document:6NAS-410 Certification and Qualification of NondestructiveTest Personnel2.6 ISO Standard:7
18、EN 60825-1 Safety of Laser Products - Part 1: EquipmentClassification, Requirements, and Users Guide3. Terminology3.1 DefinitionsDefinition of terms related to structuralsandwich constructions, NDT, and composites appearing inTerminologies C 274, E 1316, and D 3878, respectively, shallapply to the t
19、erms used in this practice.3.2 Definitions:3.2.1 aerospaceany component that will be installed on asystem that flies.3.2.2 beam splitteran optical element capable of splittinga single beam of coherent laser light into two beams. Beamsplitters are key elements of Michelson Type Image ShearingInterfer
20、ometers.3.2.3 cognizant engineering organizationsee Terminol-ogy E 1316.3.2.4 coherent light sourcea light source that convertselectrical energy to a monochromatic beam of light havinguniform phase over a minimum specified length known as thecoherent length.3.2.5 componentthe part(s) or element(s) o
21、f a systemdescribed, assembled, or processed to the extent specified bythe drawing.3.2.6 composite materialsee Terminology D 3878.3.2.7 composite componenta finished part containingcomposite material(s) that is in its end use application configu-ration and which has undergone processing, fabrication
22、, andassembly to the extent specified by the drawing, purchaseorder, or contract.3.2.8 composite shella multilayer filament winding thatcomprises a second shell that reinforces the inner shell. Thecomposite shell consists of continuous fibers, impregnated witha matrix material, wound around the inne
23、r shell, and cured inplace. An example is the Kevlar epoxy filament woundspherical shell shown in Figure 1 in Practice E 1736. Thenumber of layers, fiber orientation, and composite shell thick-ness may vary from point to point.3.2.9 composite over-wrapped pressure vessel, (COPV)see filament-wound pr
24、essure vessel.3.2.10 core crusha collapse, distortion, or compression ofcore material in a sandwich structure.3.2.11 core separationa partial or complete breaking ofhoneycomb core node bonds.3.2.12 disbond, unbond see Terminology D 3878.3.2.13 de-correlationloss of shearography phase datacaused by t
25、est part deformation exceeding the resolution of theshearing interferometer or motion occurs between the testobject and shearing interferometer during data acquisition.3.2.14 delaminationsee Terminology D 3878.3.2.15 displacement derivatives (w/x)rate of spatial dis-placement change, where w is the
26、surface displacement and xis the surface coordinates.3.2.16 excitation methodapplied stress to a test objectused in laser holographic or laser shearographic examination toaffect motion at the surface of the test object.3.2.17 filament-wound pressure vesselan inner shell overwrapped with composite la
27、yers that form a composite shell.The inner shell or liner may consist of an impervious metallicor nonmetallic material. The vessel may be cylindrical orspherical and will have at least one penetration with valveattachments for introducing and holding pressurized liquids orgases. Also referred to as
28、a Composite Over-Wrapped PressureVessel or COPV.3.2.18 flaw, nan imperfection or discontinuity that may bedetectable by nondestructive testing and is not necessarilyrejectable.3.2.19 fringe patterna set of lines in a subtraction orwrapped phase shearogram that represents the locus of equalout-of-pla
29、ne deformation derivative.3.2.20 impact damagefracturing of epoxy matrix, fiberbreakage, inter-laminar delamination of monolithic compos-ites, composite sandwich structure face sheets or filament-wound composite pressure vessels due to impact, characterizedby visible dimple surface compression, or f
30、iber breakagecaused by impact strike and non-visible subsurface matrixcracking and delamination.3.2.21 inclusionforeign objects or material including butnot limited to particles, chips, backing films, razor blades, ortools of varying sizes which are inadvertently left in acomposite lay-up.3.2.22 ind
31、icationthe observation or evidence of a condi-tion resulting from the shearographic examination that requiresinterpretation to determine its significance, characterized bydimensions, area, s/n ratio, or other quantitative measurement.3.2.23 laser shearography inspection, shearography inspec-tion, sh
32、earographyinspection method utilizing interferomet-ric imaging of deformation derivatives compared betweendifferent strain states and designed to reveal non-homogeneities, material changes and structural defectsthroughout the volume of the material.3.2.24 out-of-plane displacementthe local deformati
33、on ofa test part, normal to the surface, caused by the application ofan engineered force acting on a non-homogeneity or defect ina composite material.3.2.25 polymer matrix compositeany fiber reinforcedcomposite lay-up consisting of laminae (plies) with one ormore orientations with respect to some re
34、ference direction thatare consolidated by press, vacuum bagging, or autoclave toyield an engineered part article or structure.5Available fromAmerican Society for Nondestructive Testing (ASNT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.6Available from Aerospace In
35、dustries Association of America, Inc. (AIA), 1000Wilson Blvd., Suite 1700,Arlington, VA22209-3928, http:/www.aia-aerospace.org.7Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.E25810723.2.26 porositycondition of trapped po
36、ckets of air, gas, orvoid within solid materials, usually expressed as a percentageof the total nonsolid volume (solid + nonsolid) of a unitquantity of material.3.2.27 sandwich core materialan engineered part, article,or structure made up of two or more sheets of compositelaminate, metal, or other m
37、aterial designed to support in-planetensile or compressive loads, separated by and bonded to innercore(s) material(s) designed to support normal compressiveand tensile loads such as metal or composite honeycomb, openand closed cell foam, wave formed material, bonded compositetubes, or naturally occu
38、rring material such as end grain balsawood. Also referred to as a structural sandwich construction,see Terminology C 274.3.2.28 scan plana designed sequence of steps for posi-tioning and adjusting a shearography camera to accomplish adesired inspection. Scan plans shall include camera field ofview,
39、percentage of image overlap, position sequences for eacharea to be tested, test number, and location in a coordinatesystem appropriate for test object geometry and access.3.2.29 shearogramthe resulting image from the complexarithmetic combination of interferograms made with an imageshearing interfer
40、ometer and presented for interpretation invarious image processing algorithms including wrapped phasemaps (static or real-time), unwrapped phase maps, or inte-grated, Doppler shift map.3.2.30 shearography camera, shear cameraan imageshearing interferometer used for shearography nondestructivetesting
41、, usually including features for adjustment of focus, iris,zoom, shear vector, and projection and adjustment of coherentlight onto the test object area to be inspected.3.2.31 shear vectorthe separation vector between twoidentical images of the target in the output of an image shearinginterferometer.
42、 The Shear vector is expressed in degrees ofangle from the X axis, with a maximum of 90, with + being inthe positive Y direction and in the negative Y direction. Theshear distance between identical points in the two shearedimages expressed in inches or millimetres. (See Fig. 1).3.2.32 stressing devi
43、cethe means to apply a measurableand repeatable engineered stress to the test object duringshearography inspection. The applied stress may be in the formof a partial vacuum, pressure, heat, mechanical or acousticvibration, magnetic field, electric field, microwave, or me-chanical load. Also referred
44、 to as excitation or excitationmethod.3.2.33 voidan empty, unoccupied space in laminate. Voidsare associated with bridging and resin starved areas.4. Summary of Practice4.1 Shearography nondestructive inspection refers to the useof an image shearing interferometer to image local out-of-planedeformat
45、ion derivatives on the test part surface in response toa change in the applied engineered load. Shearography imagestend to show only the local deformation on the target surfacedue to the presence of a surface or subsurface flaw, delamina-tions, core damage, or core splice joint separations, as well
46、asimpact damage.4.2 Typical applied loads to the test part are dependant onthe test part material reaction to the induced load. The optimumload type and magnitude depend on the flaw type and flawdepth and are best determined before serial testing by makingtrial measurements. Care is taken to ensure
47、that the magnitudeof the applied load is acceptably below the damage threshold ofa given test article. The applied load can be any of thefollowing: heat, mechanical vibration, acoustic vibration, pres-sure and vacuum, electric fields, magnetic fields, microwave,or mechanical load.4.3 Shearography ND
48、T systems use a common path Mich-elson, birefringent, or beam splitter type shearing interferom-eter for imaging defects. Some of the most current technologyshearography cameras often use a Michelson type interferom-eter, Fig. 2, with phase stepping capability. The shearographyNDT procedure consists
49、 of illuminating a test article with fixedfrequency laser light before and after a small proof load isapplied. A mirror (the tilt mirror), or other optical device isprecisely adjusted to induce an offset, or sheared image, of theFIG. 1 Shear vector angle convention: Starting with the shear camera adjusted for a 0 shear condition, the sheared image is moved tothe right (+X) or up/down, never adjusted in the direction of X. For a +45 shear vector, the image is moved in the +X and +Ydirection. For 60 shear vector, the image is adjusted in t
