1、Designation: E990 13Standard Specification forCore-Splice Adhesive for Honeycomb Sandwich StructuralPanels1This standard is issued under the fixed designation E990; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This specification covers core-splice
3、adhesive 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,
4、and 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 e
5、ither 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 6, of this specification: Thisstandard d
6、oes 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 Stan
7、dards:2B209 Specification for Aluminum and Aluminum-AlloySheet and PlateC393/C393M Test Method for Core Shear Properties ofSandwich Constructions by Beam FlexureD792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementE631 Terminology of Building Construction
8、sE864 Practice for Surface Preparation of Aluminum Alloysto Be Adhesively Bonded in Honeycomb Shelter PanelsE865 Specification for Structural Film Adhesives for Hon-eycomb Sandwich PanelsE874 Practice for Adhesive Bonding of Aluminum Facingsto Nonmetallic Honeycomb Core for Shelter PanelsE1091 Speci
9、fication for Nonmetallic Honeycomb Core forUse in Shelter PanelsE1749 Terminology Relating to Rigid Wall RelocatableShelters2.2 Federal Standards:3QQ-A-250/4 Aluminum Alloy 2024, Plate and SheetQQ-A-250/8d Aluminum Alloy 5052H34, Plate and SheetQQ-A-250/11d Aluminum Alloy 6061T6, Plate and Sheet2.3
10、Military Standards:3MIL-S-8802 Sealing Compound, Temperature-Resistant,Integral Fuel Tanks, and Fuel Cell Cavities, High-Adhesion3. Terminology3.1 DefinitionsSee Terminologies E631 and E1749 fordefinitions of general terms used in this specification.4. Materials and Manufacture4.1 The adhesive shall
11、 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.5. Requirements5.1 MaterialThe adhesive shall be thermosetting andwhen tested in accordance with Sectio
12、n 6, 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.1This specification is under the jurisdiction of ASTM Committee E06 onPerformance of Buildings and is th
13、e direct responsibility of Subcommittee E06.53on Materials and Processes for Durable Rigidwall Relocatable Structures.Current edition approved Oct. 1, 2013. Published February 2014. Originallyapproved in 1984. Last previous edition approved in 2009 as E990 09. DOI:10.1520/E0990-13.2For referenced AS
14、TM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from DLA Document Services, Building 4/D, 700 Robbins Avenue,Philade
15、lphia, PA 19111-5094, http:/quicksearch.dla.mil/.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1This adhesive shall be compatible and capable of co-curingwith the structural film adhesive (Specification E865) used tofabricate the pan
16、el.5.2 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.5.3 Working Characteristics:5.3.1 ApplicationThe adhesive shall be suitable for appli-cation to core material, edge membe
17、rs, and integral parts inaccordance with the manufacturers instructions at tempera-tures from 18 to 30C (65 to 85F) and at relative humidities ofup to 50 %.5.3.2 CuringThe time, temperature, and pressure used tocure the adhesive shall be as specified herein.5.3.2.1 Curing Time and TemperatureThe adh
18、esive shallmeet the requirements of this specification when cured inaccordance with manufacturers recommendation so long asthe time and bondline temperature do not exceed1hor145C(293F).5.3.2.2 Curing PressureThe pressure required for curingthe adhesive shall be contact.5.4 Storage LifeThe adhesive s
19、hall 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 5.3.1, the adhesive shallhave a cumulative out-life of at least 5 days at 24 6 3C (756 5F).5.5 PropertiesThe properties of the test sp
20、ecimens pre-pared and tested as described herein shall conform to therequirements of Table 1.6. Test Methods6.1 Water Migration Test:6.1.1 The core Splice Adhesive Mold is illustrated in Fig. 1(Note 1). Apply a mold release agent to both the interior of thefemale portion and the exterior of the male
21、 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 the male portionuntil it seats against the base o
22、f 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, acrylic plastic, or othersuitable material. The out
23、er shell may be fabricated as a split mold.NOTE 2Depending on the expansion ratio and the unexpandedthickness of the material being tested, it may be necessary to install morethan one layer of adhesive. The size of the adhesive shall be calculated asfollows: Length width thickness = 1.65 cm3(0.65 in
24、.3).6.1.2 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.6.1.3 Cover a piece of aluminum (approx. 50 50 6 mm)(2214 in.) with MIL-S-8802, Class B-2 Sealant, orequivalent, to
25、 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).6.1.4 Place the prepared sample of adhesive (6.1.2)onthesealant and seat it gently into the sealer. Allow the sea
26、lant tocure at room temperature overnight.6.1.5 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 MIL-S-8802, Class B-2 sealant, or equiva-lent. Allow the sealant
27、 to cure at room temperature overnight.6.1.6 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. Measure the volume required to fill the cell.TABLE 1 Physical Prop
28、erties Qualification RequirementsTableReferenceParagraphRequirementsWater migration 6.1 Not more than the volume ofthe cavity (in cell)Volatility 6.2 1 % maximumExpansion 6.3 1.75 minimum ratioSag for 1.27 mm (0.05 in.)uncured thickness6.4 3.8 mm (0.15 in.) maximumSag for 2.54 mm (0.1 in.)uncured th
29、ickness6.4 12.7 mm (0.500 in.) maximumDensity (cured) 6.5 0.8 g per cm3(50 lb/ft3)maximumFlexural shear (assemblycompatibility)6.6 Same as honeycomb core,minimum 1.24 MPa (180 psi)L-directionTube shear (core spliceintegrity)6.7 Minimum average 4.13 MPa(600 psi)Minimum individual 3.1 MPa(450 psi)FIG.
30、 1 Core Splice Adhesive MoldE990 1326.1.7 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.6.1.8 The water migratio
31、n 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.6.2 Volatile TestVolatility of the film adhesive shall betested in accordance with the procedure in 6.2.1 6.2.9.6
32、.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.6.2.2 Weigh the containers that will be used in the cure ofthe test specimens cut in 6.2.1. Each container shall be analuminum moisture dish, of sufficient s
33、ize 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.)6.2.3 Place each specimen in a container, then place thecontainers in a desiccator that contains a desiccant such asdryerite for 2 h 6 10 min at room tempera
34、ture, 24 6 3C (756 5F).6.2.4 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.)6.2.5 Cure the specimens in a forced-air circulating oven.The time and temperature shall be in accordance wit
35、h 5.3.2.1.When a cure temperature range is specified, the volatility testshall be conducted at the maximum curing temperature.6.2.6 Remove the containers and cured specimens from theoven while at cure temperature, and place in a desiccator andcool to room temperature, 24 6 2.8C (75 6 5F).6.2.7 Remov
36、e the cooled containers and specimens from thedesiccator and reweigh. This weight shall be designated as W3.(W3= weight of cured adhesive and container.)6.2.8 The percent weight loss shall be calculated as follows:V 5W22 W3W22 W13100 (1)where:V = weight loss (volatility), %,W1= weight of container,
37、g (oz),W2= weight of container plus weight of uncured adhesive, g(oz), andW3= weight of cured adhesive and container, g (oz).6.2.9 The percent of weight loss of three specimens shall beaveraged and reported as volatility.6.3 Expansion TestCut three specimens of the core spliceadhesive (approx. 102 1
38、02 mm) (4 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, exposed face down, on a piece of heat resistantrelease material, being
39、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 5.3.2.1.FIG. 2 Water Migration Test Specimen AssemblyFIG. 3 Water Migration TestE990 133Record the a
40、verage thickness (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 3100 (2)where:E = expansion ratio,A = thickness of the cured film (no liner), mm (in.), andB =
41、 thickness of uncured film (with liners) minus thecombined thickness of liners, mm (in.).6.4 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 one edge of each specimen againsta 153-mm (6-in.) long scribed lin
42、e 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 with 5.3.2.1. After curing, measure thedistance the material has sa
43、gged or slumped below the scribedline and record.6.5 DensityThe density of the cured film adhesive shall betested in accordance with Test Methods D792, Method A(Displacement of Water).6.6 Shear Strength Test (Core Splice):6.6.1 The following materials shall be used to fabricatesandwich specimens of
44、76-mm (3-in.) width by 381-mm(15-in.) length by 53-mm (2.10-in.) thickness size:6.6.1.1 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 B209).6.6.1.2 51-mm (2-in.) thick Type IV honeycomb core meet-ing Specifica
45、tion E1091.6.6.1.3 Structural film adhesive meeting Specification E865.6.6.1.4 1.3-mm (0.050-in.) thick core splice adhesive asspecified in this specification.6.6.2 Three individual sandwich specimens shall be fabri-cated with core splice adhesive being used to form a splice inthe L (longitudinal) d
46、irection of the core across the 76-mm(3-in.) specimen width at the location specified in 6.6.3 (seeSpecification E1091 for orientation of core material). Note thataluminum skins shall be cleaned and etched in accordance withPractice E864 and bonded to the core in accordance withPractice E874.6.6.3 S
47、andwich specimens shall be tested at 24 6 2.8C (756 5F) in accordance with Test Method C393/C393M withmodifications as stated herein, using a 305-mm (12-in.) span(see Fig. 3). The two upper loading points and the two supportpoints shall employ 51 by 76 by 6.4-mm (2 by 3 by14-in.)loading blocks. The
48、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 in Fig. 4. The load shall be applied through a constantrate of movemen
49、t of the head of the testing machine, and atsuch a rate that the maximum load will occur between 3 and 5min.6.7 Tube Shear Test:6.7.1 Tube shear specimens shall be fabricated from drawnaluminum concentric tubes made from 5052-O, QQ-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.).6.7.2 Following cutting to length and deburri
