1、Designation: E990 09Standard 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 Department of Defense.1. Scope1.1 This specification covers core-splice adhes
3、ive 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, and r
4、elative 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 either
5、 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 does n
6、ot 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 Standards
7、:2B209 Specification for Aluminum and Aluminum-AlloySheet and PlateC393 Test Method for Flexural Properties of SandwichConstructionsD792 Test Methods for Density and Specific Gravity (Rela-tive Density) of Plastics by DisplacementE864 Practice for Surface Preparation of Aluminum Alloysto Be Adhesive
8、ly 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 Specification for Nonmetallic Honeycomb Core forUse in Shelter Panels2.2 Fed
9、eral 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-Adhesion3
10、3. 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. Requirements4.1 MaterialThe adhesive shall be ther
11、mosetting 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 and capable of co-cu
12、ringwith the structural film adhesive (Specification E865) 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.1This specification is under the juris
13、diction of ASTM Committee E06 onPerformance of Buildings and is the direct responsibility of Subcommittee E06.53on Materials and Processes for Durable Rigidwall Relocatable Structures.Current edition approved Nov. 1, 2009. Published December 2009. Originallyapproved in 1984. Last previous edition ap
14、proved in 2004 as E990 04. DOI:10.1520/E0990-09.2For referenced ASTM 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 fr
15、om Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.3 Working Characteristics:4.3.1 Applicatio
16、nThe adhesive shall be suitable for appli-cation to core material, edge members, 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 %.4.3.2 CuringThe time, temperature, and pressure used tocure the adh
17、esive shall be as specified herein.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 re
18、quired for curingthe adhesive 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
19、 least 5 days at 24 6 3C (756 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
20、 agent to both the interior of 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 lower
21、ing the female portion over the 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
22、 may be made of aluminum, acrylic 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 ad
23、hesive shall be calculated asfollows: 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
24、(approx. 50 3 50 3 6mm) (2 3 2 314 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 prepa
25、red sample of adhesive (5.1.2)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 tub
26、e and thetest specimen with MIL-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
27、 that no air isentrapped. Measure 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 ent
28、rapped air.5.1.8 The water migration 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.TABLE 1 Physical Properties Qualification RequirementsTableReferenceParagraphR
29、equirementsWater 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 2.54 mm (0.1 in.)uncured thickness5.4 12.7 mm (0.500 in.) maximumDensity (cured) 5.5
30、 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 individual 3.1 MPa(450 psi)FIG. 1 Core Splice Adhesive MoldE990 0925.2 Volatile TestVola
31、tility of the film adhesive shall betested in accordance with the procedure in 5.2.1-5.2.9.5.2.1 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 te
32、st specimens cut in 5.2.1. Each 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 thecontainer
33、s in a desiccator that contains 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 sp
34、ecimens in a forced-air circulating 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 tempera
35、ture, and place in a desiccator 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 fo
36、llows:V 5W22 W3W22 W13 100 (1)where: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
37、as volatility.5.3 Expansion TestCut 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 lin
38、er and place theadhesive, exposed 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
39、.2.1.Record the average 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 3 100 (2)where:E = expansion ratio,A = thickness of the cured film (no liner)
40、, mm (in.), andFIG. 2 Water Migration Test Specimen AssemblyFIG. 3 Water Migration TestE990 093B = thickness of uncured film (with liners) minus thecombined thickness of liners, mm (in.).5.4 Sag TestCut three specimens of the core splice adhe-sive (approx. 102 by 102 mm) (4 by 4 in.). Remove both pi
41、ecesof liner material and place 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 t
42、he specimen.Cure in accordance with 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 D792, Method A(Displacement of Water).5.6 Shear Strength
43、 Test (Core Splice):5.6.1 The following 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, respecti
44、vely, or Specification B209).5.6.1.2 51-mm (2-in.) thick Type IV honeycomb core meet-ing Specification E1091.5.6.1.3 Structural film adhesive meeting Specification E865.5.6.1.4 1.3-mm (0.050-in.) thick core splice adhesive asspecified in this specification.5.6.2 Three individual sandwich specimens s
45、hall be fabri-cated with core 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 E1091 for orientation of core material). Note thataluminum skins shall be cleaned and etc
46、hed in accordance withPractice E864 and bonded to the core in accordance withPractice E874.5.6.3 Sandwich specimens shall be tested at 24 6 2.8C (756 5F) in accordance with Test Method C393 with modifica-tions as stated herein, using a 305-mm (12-in.) span (see Fig.3). The two upper loading points a
47、nd the two support pointsshall 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 botto
48、m support point asshown in 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 t
49、ubes 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.).5.7.2 Following cutting to length and deburring, aluminumtubes shall be cleaned and etched in accordance with PracticeE864.5.7.3 The quantity of adhesive required to fill the tube shearassembly annular volume of approximately 65 cm3(4 in.3)must be determined experimen
