1、Designation: B831 11B831 14Standard Test Method forShear Testing of Thin Aluminum Alloy Products1This standard is issued under the fixed designation B831; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers single shear testing of thin wrought and cast aluminum alloy products to determine shear ultimatestrengths. I
3、t is intended for products that are too thin to be tested according to Test Method B769.1.2 The values stated in inch-pound units are to be regarded as standard. The SI values given in parentheses are mathematicalconversions to SI units that are provided for information only.only and are not conside
4、red standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. R
5、eferenced Documents2.1 The following documents of the issue in effect on the date of material purchase, unless otherwise noted, form a part of thisspecification to the extent referenced herein:2.2 ASTM Standards:2B565 Test Method for Shear Testing of Aluminum and Aluminum-Alloy Rivets and Cold-Headi
6、ng Wire and RodsB769 Test Method for Shear Testing of Aluminum AlloysE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE2208 Guide for Evaluating Non-Contacting Optical Strain Measurement Systems3. Terminology3.1 DefinitionsThe definitions
7、 of terms relating to shear testing in Terminology E6 are applicable to the terms used in this testmethod.4. Summary of Test Method4.1 This test method consists of subjecting a full thickness or machined rectangular test specimen to single shear force to failurein a test fixture using a tension test
8、ing machine. The shear strength is calculated from the maximum force required to fracture thespecimen.5. Significance and Use5.1 The intent of this test method is to provide a means of measuring the ultimate shear strength of thin aluminum alloy wroughtand cast products. It is recognized that the lo
9、ading conditions developed by this test method, and by most others, are not ideal inthat they do not strictly satisfy the definitions of pure shear. However, rarely do pure shear conditions exist in structures.NOTE 1Results from this test method are not interchangeable with results from Test Methods
10、 B565 and B769. Shear strengths obtained by this testmethod have been shown to differ from values determined with other methods.36. Apparatus6.1 Testing MachinesThe testing machines shall conform to the requirements of Practice E4. The maximum force used todetermine the shear strength shall be withi
11、n the verified force range of the testing machine as defined in Practice E4.1 This test method is under the jurisdiction of ASTM Committee B07 on Light Metals and Alloyss and is the direct responsibility of Subcommittee B07.05 on Testing.Current edition approved Nov. 1, 2011May 1, 2014. Published Ja
12、nuary 2012July 2014. Originally approved in 1993. Last previous edition approved in 20052011 asB831 05.B831 11. DOI: 10.1520/B0831-11.10.1520/B0831-14.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Stan
13、dardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Davies, R. E., and Kaufman, J. G., “Effects of Test Method and Specimen Orientation on Shear Strengths of Aluminum Alloys,” Proceedings, ASTM, Vol 64, 1964.This document is not an ASTM standard and is intende
14、d only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current
15、versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.2 Loading Device:6.2.1 The device
16、 for applying force to the specimen from the testing machine shall be a clevis of the type shown in Fig. 1 andshall be made of a hardened steel.7. Test Specimens7.1 The specimen size shall be 1.5 in. (38.1 mm) wide by 4.5 in. (114 mm) long. The specimen geometry is shown in Fig. 2.The specimen thick
17、ness shall be the full product thickness for a product thickness of 0.250 in. (6.35 mm) or less. For a productthickness greater than 0.250 in. (6.35 mm), the specimen shall be machined to a thickness of 0.250 in. (6.35 mm) by machiningequal amounts from each side of the product. The minimum specimen
18、 thickness that can be reasonably tested will be dictated bythe materials ability to resist buckling around the pin hole area during testing.7.2 The test area to be sheared shall be centered within 0.001 in. (0.025 mm) of the load line of the specimen.7.3 Measure and record the thickness (t) and len
19、gth (L) of the area to be sheared. Measurements shall be made as follows:7.3.1 Measurement of the specimen thickness shall be made at a location between the two slots machined into the specimen.Measurement of the length of the shear area shall be between the ends of the slots machined into the speci
20、men, Fig. 2. Fordimensions 0.200 in. (5.1 mm) and over, measure to the nearest 0.001 in. (0.025 mm). For dimensions less than 0.200 in. (5.1 mm)and not less than 0.100 in. (2.5 mm), measure to the nearest 0.0005 in. (0.013 mm). For dimensions less than 0.100 in. (2.5 mm),measure to the nearest 0.000
21、1 in. (0.0025 mm).7.4 All machined surfaces in the test area shall have a surface finish of 32 in. (0.80 m) Ra or less.FIG. 1 Slotted Single Shear Test FixtureB831 1428. Specimen Orientation and Direction8.1 The shear strength of wrought aluminum materials usually depends on the specimen orientation
22、 and the direction in whichthe load is applied relative to the grain flow in the specimen.3 The specimen orientation and the loading direction should beidentified by the following systems.8.1.1 The reference directions for rectangular shapes are indicated in Fig. 3. These are suitable for sheet, pla
23、te, extrusions,forgings, and other shapes having nonsymmetrical grain flow.8.2 The two-letter code is used in Fig. 3 to describe the specimen orientations and loading directions. The first letter designatesthe normal to the expected shear plane. The second letter designates the direction of force ap
24、plication or expected fracturedirection. The most commonly used specimen orientations and loading directions are T-L and L-T for in-plane shear strength ofthin products. This orientation code is identical to that used for cylindrical shear specimens in Test Method B769.NOTE 2These orientation codes
25、are analagous to those used for fracture specimens if the first letter is interpreted as the normal to the fracture planeand the second letter is the direction of fracture.NOTE 3Typically, cast aluminum products do not exhibit the directionality of wrought products; therefore, the orientation codes
26、are not applicableto castings.9. Procedure9.1 Measurement of SpecimensMeasure the applicable dimensions designated in 7.3 and calculate the cross-sectional area bymultiplying the two dimensions (A = t L).FIG. 2 Slotted Single Shear Test SpecimenB831 1439.2 TestingMount the specimen in the test fixtu
27、re as shown in Fig. 1. The specimen should not be restrained by clamping ofthe load pin area during the test.9.2.1 When assembling the loading train (clevises and their attachments to the testing machine), take care to minimizeeccentricity of loading due to misalignments external to the clevises. To
28、 obtain satisfactory alignment, keep the centerline of theupper and lower loading rods coincident within 0.03 in. (0.76 mm) during the test.9.2.2 The cross head speed of the testing machine shall not exceed 0.75 in./min (19.1 mm/min) and the shear stress rate shallnot exceed 100 ksi/min (689 MPa/min
29、) on the cross-section. The machine crosshead speed setting should not be adjusted duringthe test.9.2.3 Determine the maximum force Pmax to fracture the specimen.10. Calculation10.1 Calculate the shear strength from the maximum force as follows:S 5PmaxA (1)where:S = shear strength, psi (MPa),Pmax =
30、maximum force, lbf (N), andA = cross-sectional area (thickness t times distance between slots, L), in.2 (mm2).where:S = shear strength, psi (MPa),Pmax = maximum force, lbf (N), andA = cross-sectional area (thickness t times distance between slots, L), in.2 (mm2).11. Report11.1 Report the following i
31、nformation:11.1.1 ASTM method of shear test,NOTE 4Since the test method significantly influences the test results, it is essential that the ASTM method be referenced.11.1.2 Material and sample identification,11.1.3 Specimen dimensions, in in. (mm),11.1.4 Specimen orientation code,11.1.5 Maximum forc
32、e, in lbf (N),11.1.6 Shear strength, in psi (MPa), and11.1.7 Test temperature, if other than room temperature, in F (C).12. Precision and Bias12.1 The precision and bias of this test method needs to be established. Subcommittee B7.05 is developing the precision andbias statements for this test metho
33、d.FIG. 3 Grain Orientations and Specimen Orientation Codes for Slotted Single Shear Specimens from Rectangular ShapesB831 14413. Keywords13.1 aluminum; mechanical test; shear; strengthAPPENDIXX1. AN ADVANCED METHOD OF DETERMINING SHEAR STRESS-SHEAR STRAIN BEHAVIOR USING DIGITAL IMAGECORRELATION (DIC
34、) AND A MODIFIED SPECIMEN DESIGNX1.1 Two-dimensional digital image correlation system using one digital camera shall be used to measure shear straindevelopment within the shear zone during the test. The DIC system shall conform to the requirements in Guide E2208-02.X1.2 Measuring shear stress-shear
35、strain curves at large strains requires the modified specimen4 shown in Fig. X1.1. This modifiedsample geometry ensures that the zone undergoes only simple shear; it also prevents end rotation of the shear zone.X1.3 A flat and matte speckle pattern shall be applied to one side of the shear zone prio
36、r to the test. First, a white color patternshall be applied with full coverage as a background and then the black color shall be superimposed on the background as dispersedspeckles. Proper lighting (for example, polarized light) shall be used to ensure the full shear zone be viewed in the digital ca
37、mera.X1.4 Shear strain is measured as the change of an angle of 90 in the undeformed state to a new angle in the deformed state.X1.5 The shear stress, shall be calculated as: 5 PLt0(X1.1)4 Kang, J., Wilkinson, D. S., Wu, P.D., Bruhis, M., Jain, M., Embury, J. D., Mishra, R.K., “Constitutive Behavior
38、 of AA5754 Sheet Materials at Large Strains,” ASMEJournal of Engineering Materials and Technology, Vol. 130: 031004-1-5, 2008.FIG. X1.1 Modified Shear SpecimenB831 145where:P = the instantaneous applied force,L = the length of the shear zone (for example, 0.25 in. (6.35 mm) in Fig. X1.1), andt0 = th
39、e thickness of the shear zone (for example, 0.04 in. (1 mm) in Fig. X1.1).X1.5.1 From the DIC measurements, the average shear strain and/or shear angle over the shear zone shall be reported. If only shearangle, is reported, then the shear strain, is calculated as: 5tan! (X1.2)SUMMARY OF CHANGESCommi
40、ttee B07 has identified the location of selected changes to this standard since the last issue(B83105)(B83111) that may impact the use of this standard. (Approved Nov. 1, 2011May 1, 2014)(1) Corrected several typographical errors.Added Appendix.(2) Changed wording to improve clarity.ASTM Internation
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43、ddressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards,
44、at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).B831 146
