1、Designation: E 990 04Standard Specification forCore-Splice Adhesive for Honeycomb Sandwich StructuralPanels1This standard is issued under the fixed designation E 990; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This specification covers core-splice ad
3、hesive for usewith nonmetallic honeycomb cores in the fabrication of hon-eycomb sandwich panels used in relocatable structures. Theadhesive shall be used for new production or depot repair. Theadhesive shall be suitable for forming bonds that can withstandlong combinations of stress, temperature, an
4、d relative humidityexpected to be encountered in service. The adhesive shall beused for bonding core segments and for bonding core segmentsto edge members and to integral members in a honeycombsandwich panel. The adhesive shall not allow the transfer ofwater from one part of the panel to another eit
5、her through oralong the line of the adhesive.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 The following precautionary caveat pertains only to thetest method portion, Section 5, of this specification: Thisstandard doe
6、s not purport to address all of the safety concerns,if any, associated with its use. It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standa
7、rds:2B 209 Specification for Aluminum and Aluminum-AlloySheet and PlateC 393 Test Method for Flexural Properties of SandwichConstructionsD 792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementE 864 Practice for Surface Preparation ofAluminumAlloysto be Adh
8、esively Bonded in Honeycomb Shelter PanelsE 865 Specification for Structural Film Adhesives for Hon-eycomb Sandwich PanelsE 874 Practice forAdhesive Bonding ofAluminum Facingsto Nonmetallic Honeycomb Core for Shelter PanelsE 1091 Specification for Nonmetallic Honeycomb Core forUse in Shelter Panels2
9、.2 Federal Standards:QQ-A-250/4 Aluminum Alloy 2024, Plate and Sheet3QQ-A-250/8d Aluminum Alloy 5052H34, Plate and Sheet3QQ-A-250/11d Aluminum Alloy 6061T6, Plate and Sheet32.3 Military Standards:MIL-S-8802 Sealing Compound, Temperature-Resistant,Integral Fuel Tanks, and Fuel Cell Cavities, High-Adh
10、esion33. Materials and Manufacture3.1 The adhesive shall be free of foreign materials, benoncorrosive to the metal parts, and have the structuralintegrity equal to or better than that of an unspliced panelsection as specified in Table 1, Flexural Sheer.4. Requirements Requirements4.1 MaterialThe adh
11、esive shall be thermosetting andwhen tested in accordance with Section 5, shall meet therequirements of Table 1. The adhesive shall not have adeleterious effect on the panel nor on its component parts overthe range of temperature at which the adhesive will be used.This adhesive shall be compatible a
12、nd capable of co-curingwith the structural film adhesive (Specification E 865) used tofabricate the panel.4.2 FormThe adhesive shall be of film form either 1.27mm (0.051 in.) or 2.54 mm (0.100 in.) thick and shall becapable of expanding to at least 1.75 times its originalthickness.4.3 Working Charac
13、teristics:4.3.1 ApplicationThe adhesive shall be suitable for appli-cation to core material, edge members, and integral parts in1This specification is under the jurisdiction of ASTM Committee E06 onPerformance of Buildings and is the direct responsibility of Subcommittee E06.53on Materials and Proce
14、sses for Durable Rigid Wall Relocatable Structures.Current edition approved April 1, 2004. Published April 2004. Originallyapproved in 1984. Last previous edition approved in 1998 as E 990 98.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at ser
15、viceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-50981Copyright ASTM International, 100 Barr Har
16、bor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.accordance with the manufacturers instructions at tempera-tures from 18 to 30C (65 to 85F) and at relative humidities ofup to 50 %.4.3.2 CuringThe time, temperature, and pressure used tocure the adhesive shall be as specified he
17、rein.4.3.2.1 Curing Time and TemperatureThe adhesive shallmeet the requirements of this specification when cured inaccordance with manufacturers recommendation so long asthe time and bondline temperature do not exceed1hor145C(293F).4.3.2.2 Curing PressureThe pressure required for curingthe adhesive
18、shall be contact.4.4 Storage LifeThe adhesive shall have a minimumstorage life of 3 months from the date of receipt at thefabricator facility when stored at 17.8C (0F) or below.Under conditions in accordance with 4.3.1, the adhesive shallhave a cumulative out-life of at least 5 days at 24 6 3C (756
19、5F).4.5 PropertiesThe properties of the test specimens pre-pared and tested as described herein shall conform to therequirements of Table 1.5. Test Methods5.1 Water Migration Test:5.1.1 The core Splice Adhesive Mold is illustrated in Fig. 1(Note 1). Apply a mold release agent to both the interior of
20、 thefemale portion and the exterior of the male portion of the mold.Install a layer of adhesive (Note 2) on the entire length of the19.05 mm diameter part of the male portion of the mold so thatthe layer of adhesive overlaps along a vertical seam. Close themold by lowering the female portion over th
21、e male portionuntil it seats against the base of the male portion. A press maybe used to help close the mold. Remove the mold from thepress and place in an oven. Cure in the oven at 121 6 5.6C(250 6 10F) for 1 h minimum. Remove cured adhesive fromthe mold.NOTE 1The mold may be made of aluminum, acry
22、lic plastic, or othersuitable material. The outer shell may be fabricated as a split mold.NOTE 2Depending on the expansion ratio and the unexpanded thick-ness of the material being tested, it may be necessary to install more thanone layer of adhesive. The size of the adhesive shall be calculated asf
23、ollows: Length 3 width 3 thickness = 1.65 cm3(0.65 in.3).5.1.2 Prepare the sample (approximately 38 mm (112 in.)long) by cutting the cylinder of cured adhesive and visuallycheck to ensure that there are no cracks, pin holes, and so forth.5.1.3 Cover a piece of aluminum (approx. 50 3 50 3 6mm) (2 3 2
24、 314 in.) with MIL-S 8802, Class B-2 Sealant, orequivalent, to a depth of 3 to 6 mm (18 to14 in.). Use a “dam,”such as vacuum-bagging putty or an aluminum foil tray, aroundthe edge of the aluminum to prevent the sealant from runningoff (see Fig. 2).5.1.4 Place the prepared sample of adhesive (5.1.2)
25、onthesealant and seat it gently into the sealer. Allow the sealant tocure at room temperature overnight.5.1.5 Install a glass tube approximately 38 mm (112 in.)long approximately 19 mm (34 in.) down into the hole in thetop of the specimen, and seal between the glass tube and thetest specimen with MI
26、L-S-8802, Class B-2 sealant, or equiva-lent. Allow the sealant to cure at room temperature overnight.5.1.6 Fill the cell in the sample through the glass tube withdistilled water using a hypodermic needle. Inject the water atthe bottom to ensure that the cell is full and that no air isentrapped. Meas
27、ure the volume required to fill the cell.5.1.7 Connect a buret filled with distilled water to the glasstube using a clear polyethylene tubing (see Fig. 3). Adjust theburet to a height of 914.4 mm (36 in.) above the top of the testspecimen and ensure that there is no entrapped air.5.1.8 The water mig
28、ration through the adhesive tube speci-men shall not exceed the number of millilitres required to fillthe cavity (approximately 12 mL (0.4 oz) when subjected to a915 mm (36-in.) head for 24 h.5.2 Volatile TestVolatility of the film adhesive shall betested in accordance with the procedure in 5.2.1-5.
29、2.9.TABLE 1 Physical Properties Qualification RequirementsTableReferenceParagraphRequirementsWater migration 5.1 Not more than the volume ofthe cavity (in cell)Volatility 5.2 1 % maximumExpansion 5.3 1.75 minimum ratioSag for 1.27 mm (0.05 in.)uncured thickness5.4 3.8 mm (0.15 in.) maximumSag for 2.
30、54 mm (0.1 in.)uncured thickness5.4 12.7 mm (0.500 in.) maximumDensity (cured) 5.5 0.8 g per cm3(50 lb/ft3)maximumFlexural shear (assemblycompatibility)5.6 Same as honeycomb core,minimum 1.24 MPa (180 psi)L-directionTube shear (core spliceintegrity)5.7 Minimum average 4.13 MPa(600 psi)Minimum indivi
31、dual 3.1 MPa(450 psi)FIG. 1 Core Splice Adhesive MoldE9900425.2.1 Cut the adhesive into three one-ply test specimens.Each specimen is to be a 51-mm (2-in.) diameter disk or 51 by51-mm (2 by 2-in.) square.5.2.2 Weigh the containers that will be used in the cure ofthe test specimens cut in 5.2.1. Each
32、 container shall be analuminum moisture dish, of sufficient size to allow the speci-men to lie in the bottom without the edges of the specimentouching the side of the container. (W1= weight of container.)5.2.3 Place each specimen in a container, then place thecontainers in a desiccator that contains
33、 a desiccant such asdryerite for 2 h 6 10 min at room temperature, 24 6 3C (756 5F).5.2.4 Remove the container and specimen from the desic-cator and weigh. This weight shall be designated as W2.(W2= weight of container plus weight of uncured adhesive.)5.2.5 Cure the specimens in a forced-air circula
34、ting oven.The time and temperature shall be in accordance with 4.3.2.1.When a cure temperature range is specified, the volatility testshall be conducted at the maximum curing temperature.5.2.6 Remove the containers and cured specimens from theoven while at cure temperature, and place in a desiccator
35、 andcool to room temperature, 24 6 2.8C (75 6 5F).5.2.7 Remove the cooled containers and specimens from thedesiccator and reweigh. This weight shall be designated as W3.(W3= weight of cured adhesive and container.)5.2.8 The percent weight loss shall be calculated as follows:V 5W22 W3W22 W13 100 (1)w
36、here:V = weight loss (volatility), %,W1= weight of container, g (oz),W2= weight of container plus weight of uncured adhesive,g (oz), andW3= weight of cured adhesive and container, g (oz).5.2.9 The percent of weight loss of three specimens shall beaveraged and reported as volatility.5.3 Expansion Tes
37、tCut three specimens of the core spliceadhesive (approx. 102 3 102 mm) (4 3 4 in.) with the linersintact. Record the average thickness (at least three readings perspecimen) of the core splice adhesive and protective liners tonearest 0.025 mm (0.001 in.). Remove one liner and place theadhesive, expos
38、ed face down, on a piece of heat resistantrelease material, being careful to eliminate entrapped airbetween the core splice adhesive and the release material.Remove the second original liner from the adhesive and curethe adhesive without pressure in accordance with 4.3.2.1.Record the average thickne
39、ss (at least three readings) of thecured core splice film to the nearest 0.025 mm (0.001 in.).Measure the combined thickness of the two liners. Calculatethe expansion ratio as follows:E 5 A/B 3 100 (2)where:E = expansion ratio,A = thickness of the cured film (no liner), mm (in.), andB = thickness of
40、 uncured film (with liners) minus thecombined thickness of liners, mm (in.).FIG. 2 Water Migration Test Specimen AssemblyFIG. 3 Water Migration TestE9900435.4 Sag TestCut three specimens of the core splice adhe-sive (approx. 102 by 102 mm) (4 by 4 in.). Remove both piecesof liner material and place
41、one edge of each specimen againsta 153-mm (6-in.) long scribed line on a clean aluminum plateusing hand pressure to ensure contact and to remove entrappedair bubbles. Place the specimen vertically in an air circulatingoven so that the scribe line is at the bottom of the specimen.Cure in accordance w
42、ith 4.3.2.1. After curing, measure thedistance the material has sagged or slumped below the scribedline and record.5.5 DensityThe density of the cured film adhesive shall betested in accordance with Test Methods D 792, Method A(Displacement of Water).5.6 Shear Strength Test (Core Splice):5.6.1 The f
43、ollowing materials shall be used to fabricatesandwich specimens of 76-mm (3-in.) width by 381-mm(15-in.) length by 53-mm (2.10-in.) thickness size:5.6.1.1 1.3-mm (0.050-in.) thick 5052-H34 or 6061-T6aluminum skins (Federal Standard QQ-A-250/8d or QQ-A-250/11d, respectively, or Specification B 209).5
44、.6.1.2 51-mm (2-in.) thick Type IV honeycomb core meet-ing Specification E 1091.5.6.1.3 Structural film adhesive meeting SpecificationE 865.5.6.1.4 1.3-mm (0.050-in.) thick core splice adhesive asspecified in this specification.5.6.2 Three individual sandwich specimens shall be fabri-cated with core
45、 splice adhesive being used to form a splice inthe L (longitudinal) direction of the core across the 76-mm(3-in.) specimen width at the location specified in 5.6.3 (seeSpecification E 1091 for orientation of core material). Note thataluminum skins shall be cleaned and etched in accordance withPracti
46、ce E 864 and bonded to the core in accordance withPractice E 874.5.6.3 Sandwich specimens shall be tested at 24 6 2.8C (756 5F) in accordance with Test Method C 393 with modifica-tions as stated herein, using a 305-mm (12-in.) span (see Fig.3). The two upper loading points and the two support points
47、shall employ 51 by 76 by 6.4-mm (2 by 3 by14-in.) loadingblocks. The upper loading points shall be located at theone-third span positions. The splice must be positioned at themaximum shear load location, which is approximately 51 mm(2 in.) from the centerline of either bottom support point asshown i
48、n Fig. 4. The load shall be applied through a constantrate of movement of the head of the testing machine, and atsuch a rate that the maximum load will occur between 3 and 5min.5.7 Tube Shear Test:5.7.1 Tube shear specimens shall be fabricated from drawnaluminum concentric tubes made from 5052-O, QQ
49、-A-250/4or alloy of comparable compressive strength. The outer tubeshall have a 25-mm (1-in.) outside diameter and the inner tubea 13-mm (12-in.) outside diameter. Both tubes shall be 225-mm(9-in.) long and have a wall thickness of 1.2-mm (0.049-in.).5.7.2 Following cutting to length and deburring, aluminumtubes shall be cleaned and etched in accordance with PracticeE 864.5.7.3 The quantity of adhesive required to fill the tube shearassembly annular volume of approximately 65 cm3(4 in.3)must be determined experimentally for each adhesive. Thi
