1、AEROSPACE MATERIAL SPECIFICATION AMS3920 REV. AIssued 1984-04 Revised 1996-10 Reaffirmed 2014-08 Superseding AMS3920 Acceptance CriteriaAdhesive-Bonded Metal-Faced Sandwich Structures RATIONALE AMS3920A has been reaffirmed to comply with the SAE five year review policy. _ SAE Technical Standards Boa
2、rd Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibil
3、ity of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2014 SAE International All rights reserved. No part of this publication may be reproduced,
4、 stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (outside USA) Fax: 724-776-
5、0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AMS3920A 1. SCOPE:1.1 Application:This specification establishes the acceptance criteria and inspection requir
6、ements foradhesive-bonded sandwich structures including the metal-to-metal bonding found in thesestructures, but usage is not limited to such applications and each application should beconsidered individually.1.2 Classification:The classification of adhesive bonded structures specified in this speci
7、fication shall be of thefollowing types:Type 1: Components which are fracture or fatigue critical as defined in MIL-I-6870 andcomponents, the single failure of which would cause significant danger to operatingpersonnel or would result in an operational penalty. This includes loss of majorcomponents,
8、 loss of control, unintentional release, inability to release armament stores,or failure of weapon installation components.Type 2:All components not classified as Type 1.1.2.1 Structural Classification: The structural classification, Type 1 or Type 2, will be specified on theengineering drawing. All
9、 structures shall be considered Type 1 unless otherwise specified onthe drawing.1.2.2 Structural Imperfections: Structural imperfections specified in this specification shall beface-to-core voids and disbonds, metal-to-metal voids, bond voids, porosity, core splice voids,core splice gaps, dents, and
10、 markoffs. These imperfections are defined in 8.2.SAE INTERNATIONAL AMS3920A Page 2 of 12 2. APPLICABLE DOCUMENTS:The following publications form a part of this specification to the extent specified herein. Theapplicable issue of referenced publications shall be the issue in effect on the date of th
11、e purchaseorder.2.1 SAE Publications:Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.ARP1917 Clarification of Terms Used in Aerospace Metals Specifications2.2 U.S. Government Publications:(R)Available from DODSSP, Subscription Services Desk, Building 4D, 700 Robbins Avenue,Phil
12、adelphia, PA 191115094.MIL-I-6870 Inspection Program Requirements, Nondestructive Testing, For Aircraft and MissileMaterials and Parts3. TECHNICAL REQUIREMENTS:3.1 Procedure:3.1.13.1.2Purchaser will specify the allowable imperfections for adhesive-bonded, metal-faced structures,including metal-to-me
13、tal bonds, on the engineering drawing or in the process specification; ifnot so specified, the following requirements shall apply:Imperfection Dimensions: When measured as shown in Figure 1, individual disbonds or voidsshall not have any dimension greater than 15 times the thickness of the thinnest
14、adherend, or1 inch (25 mm), whichever is smaller, or an “S” dimension greater than 15% of the shortest W”through the defect.SAE INTERNATIONAL AMS3920A Page 3 of 12 3.1.2 (Continued):Wwhere:WS is the width of void in the “W” directionL is the longest dimension of voidW is the smallest dimension of th
15、e metal-to-metal bond area containing the void(width of adhesive bond)The width of void is in the “W“ directionWhen “W” is less than 2 inches (51 mm), “S” shall be less than 0.25 inch (6.4 mm)FIGURE 1 - Dimensions3.1.3 Permissible Areas:3.1.3.1 The maximum permissible area of an individual void or d
16、isbond is as follows:3.1.3.1 .1 Type 1 Structure: 0.375 square inch (242 mm2)3.1.3.1.2 Type 2 Structure: 0.500 square inch (323 mm2)3.1.3.23.1.3.2.1The minimum permissible spacing distance as measured in Figure 2 between voidboundaries is as follows:Type 1 Structure: Four times the largest void or d
17、isbond dimension measured on a linebetween the centers of the two voids.3.1.3.2.2 Type 2 Structure: Three times the void or disbond dimension.3.1.3.3 No voids, disbonds, or porosity shall be permitted within 0.125 inch (3.18 mm) of any bondjoint edge.3.1.3.4 The aggregate unbonded length of disbonds
18、 along any straight area, between two parallellines 0.25 inch (6.4 mm) apart shall not exceed 15% of the length of the bond line, measuredalong the direction of the parallel lines.SAE INTERNATIONAL AMS3920A Page 4 of 12 4 or 3 x FIGURE 2 - Measuring Disbond Spacing3.1.3.5 The maximum permissible voi
19、d or disbond area of the metal-to-metal bond area within anassembly is 1% on Type 1 structures, and 2% on Type 2 structures.3.1.3.6 The maximum permissible disbond area of the metal-to-metal bond area contained within a6-inch (152-mm) diameter circle is 8% of that area so contained for Type 1 and 2
20、structures.3.1.4 Face-To-Core Bonds: Voids or disbonds shall be limited to 0.50 inch (12.7 mm) diameter forType 1 and 0.75 inch (19 mm) diameter for Type 2 face-to-core or doubler-to-core bonds.3.1.5 Core Splice, Core-To-Edge Member, or Core-To-Insert Bonds:3.1.5.1 The maximum permissible core gap t
21、hat is filled with adhesive, or the equivalent, shall beequal to 0.125 inch (3.18 mm) for Type 1 structures and to one cell diameter of the largestcell common to the core joint or 0.25 inch (6.4 mm), whichever is smaller, for Type 2structures, as shown in Figures 3,4, and 5.SAE INTERNATIONAL AMS3920
22、A Page 5 of 12 1 cell diameter or0.25 inch (6.4 mm)maximum separationAdhesiveFigure 3 - Core Splice (Type 2 Structure)1 cell diameter or0.25 inch (6.4 mm) maximumNOTES: 1. The maximum void or disbond shall be 0.50 inch (12.7 mm) or three adjacent cells,whichever is smaller, for each linear foot (305
23、 mm).2 . Total void or disbond shall not exceed 5% of total core-to-insert bond area.FIGURE 4 - Core-to-Insert (Type 2 Structure)1 cell diameter or0.25 inch (6.4 mm) maximumNOTES: 1. Adhesive maximum void or disbond shall be 0.50 inch (12.7 mm) or three adjacent cells,whichever is smaller, for each
24、linear foot (305 mm).2. Total disbond shall not exceed 5% of total core-to-edge member bond area.FIGURE 5 - Core-to-Vertical Edge Member (Type 2 Structure)SAE INTERNATIONAL AMS3920A Page 6 of 12 3.1.5.2 The maximum permissible core joint void or disbond dimension shall be 0.50 inch (12.7 mm)or three
25、 adjacent cells, whichever is smaller, for each linear foot (305 mm) and shall notexceed 5% of core-to-core bond area (splice height times splice length).3.1.5.3 The maximum core-to-beveled edge member voids, disbonds, and gaps shall be as shown inFigure 6.Cutaway ViewMaximum Voidor disbond1 cellunb
26、onded perlinear foot(305 mm)(beveledclosure areaonly)0.125 inch (3.18 mmmaximum width or disbond entirelengthvoidirregular trim allowedprovided it is filledwith adhesive orequivalentFIGURE 6 - Core-to-Beveled Edge Member3.1.6 Sandwich Face Dents:3.1.6.1 Dents: Shall not exhibit creases, sharp edges,
27、 or wrinkles as shown in Figure 7. The dentarea shall be inspected for disbonds in accordance with 3.1.8.1.3.1.6.2 Dimensions:3.1.6.2.1 Diameter: The maximum permissible dent diameter shall be 1.5 inches (38 mm) for Type 1structure and 2 inches (51 mm) for Type 2 structure.3.1.6.2.2 Depth: The maxim
28、um permissible dent depth shall be 0.006 inch (0.15 mm) for Type 1structure and 0.020 inch (0.51 mm) for Type 2 structure.3.1.6.2.3 Areas: The maximum permissible dent area within an assembly is 1% on Type 1 structureand 2% on Type 2 structure.SAE INTERNATIONAL AMS3920A Page 7 of 12 SmoothTransition
29、No crimpsNo Creases/SmoothI TransitionFIGURE 7 - Sandwich Face DentsSAE INTERNATIONAL AMS3920A Page 8 of 12 3.1.6.2.4 Spacing: The minimum permissible distance between dent centers is 6 inches (152 mm) forType 1 structures and 4 inches (102 mm) for Type 2 structure. The minimum permissibledistance b
30、etween dent center and the edge of solid members is 10 inches (254 mm) forType 1 structures and 6 inches (152 mm) for Type 2 structure.3.1.6.3 Dent Limitations: Dent limitations required for cosmetic purposes shall be established bypurchasers quality assurance organization.3.1.7 Face Markoff: Markof
31、f requirements shall be in accordance with Figure 8.Maximum markoff allowed: Type 1: 0.006 inch/inch (0.006 mm/mm)Type 2: No limitFIGURE 8 - Markoff3.1.8 Destructive Inspection: Destructive inspection of an assembly shall be conducted in(R) accordance with 3.1.8.l and 3.1.8.2 to ensure that the bond
32、ed components meet the criteria ofthis specification.3.1.8.1 Destructive inspection shall be made on parts selected to ensure proper fabrication(R)of parts through the production run. Any evidence of improper cure, adhesion, misalignment,etc, shall be immediately corrected by making necessary adjust
33、ment in the cure cycles or intooling.3.1.8.1 .1 Above sampling and testing procedures apply to bonded parts that do not use formal(R) bonding tool or fixture.3.1.8.2 For short production runs of 10 or less items, destructive evaluation testing as outlined in(R) 3.1.8.1 may be waived providing 100% b
34、ond line verification is made prior to bonding of eachassembly, and 100% nondestructive testing (NDT) of each part is made in accordance with3.1.9.1 and 3.1.9.2.3.1.9 Nondestructive Inspection: Shall be in accordance with 3.1.9.1, 3.1.9.2, and 3.1.9.3.(R) Standards shall be of similar construction a
35、s the parts to be inspected and shall contain voids ordisbonds of the maximum allowable sizes.SAE INTERNATIONAL AMS3920A Page 9 of 12 3.1.9.1(R)3.1.9.2(R)3.1.9.3(R)Purchaser shall submit a complete NDT process specification when required to evaluatethe quality of adhesively bonded structures. Purcha
36、ser shall specify the type and size ofimperfections that are acceptable. The size of the allowable imperfections must be correlatedwith the capability of the NDT method to be used, realizing that NDT methods andinstrumentation have different capabilities for the testing of adhesive bonded structures
37、. Theapplication of these different NDT methods is limited by material types and designconfiguration.Nondestructive testing of adhesive bonded structures shall only be performed by qualifiedNDT personnel. Qualified NDT personnel are those who have demonstrated by passingwritten and practical profici
38、ency tests that they possess the skills and job knowledgenecessary to ensure an acceptable level of performance in the nondestructive testing ofadhesively bonded structures. A list of qualified NDT personnel shall be maintained andmade available to personnel for on-site review. Personnel qualificati
39、ons shall be reviewed atleast annually.Unless otherwise specified by purchaser, bonds shall be inspected on the followingminimum frequency as specified in Table 1.TABLE 1 - NDT FrequencyBond ConditionMetal-to-metalAssembly Assembly AreaFrequency Frequency FrequencyType 1 Type 21Types 1, 2each assemb
40、ly AQL Note 2Face-to-core sandwich each assembly AQL 6 inch (152 mm) grid, minconstruction1 Purchaser to establish inspection plan.This information to be included in the NDT process specification as required by3.1.9.1.4. QUALITY ASSURANCE PROVISIONS:4.1 Responsibility for Inspection:(R)Purchaser sha
41、ll supply the nondestructive inspection standards (3.1.9) for required tests. Themanufacturer of structures shall supply all samples for required tests and shall be responsible forperforming all required tests. Purchaser reserves the right to sample and to perform anyconfirmatory testing deemed nece
42、ssary to ensure that the structures conform to the requirementsof this specification.4.1.1 An effective quality assurance system shall be provided to ensure inspection operationperformance by personnel who have demonstrated their ability to apply these criteria(See 3.1.9.2).2SAE INTERNATIONAL AMS392
43、0A Page 10 of 12 4.2 Classification of Tests:Tests for all technical requirements are acceptance tests and shall be performed on each lot.4.2.1 A lot shall be all structures of the same configuration made from the same materials in not morethan eight consecutive hours and presented for manufacturers
44、 inspection at one time.4.3 Sampling and Testing:(R)Shall be acceptable to purchaser.4.4 Test Methods:(R)Production bonded parts shall incorporate, where possible, extensions or coupons that may becut from the parts after bonding and will be representative of the bonds obtained in the parts.Where ex
45、tensions cannot be incorporated in the parts, standard test panel specimens shall befabricated. These shall be cleaned and bonded at the same time, with the same adhesive, in thesame equipment, and under the same conditions as the assembly they represent. Theprocedures for their incorporation or fab
46、rication shall be included in the process specification.The number of extensions, coupons, or specimens shall be specified by purchaser in the processspecification.4.4.1 Destructive quality control tests shall be made of the adhesive bonds in the extensions,(R) coupons, or standard test panel specim
47、ens prepared as described in 4.4. The test proceduresto be used and the acceptance criteria shall be specified in the process specification. If the testtab per assembly method is used, daily lap shear and/or peel tests, or crack extensionspecimens shall be included in the quality assurance system as
48、 a control of the cleaningprocess.4.5 Reports:(R)The supplier of sandwich structures shall furnish with each shipment a report stating that theadhesive bonded structures have been tested in accordance with specified requirements and thatthey conform to the technical requirements and the standards sp
49、ecified by purchaser. This reportshall include full-size sketches of all structures (identified to that structure) evidencing anydiscrepancy; location and actual size of the discrepancy shall be shown. This report shall includethe purchase order number, lot number, material identification, AMS 3920A, and part numberstested.5. PREPARATION FOR DELIVERY:5.1 Identification:5.1.1 Acceptable structures shall be
