ASTM E837-2001e1 Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method《用钻孔应变仪法测定残余应力的标准试验方法》.pdf

《ASTM E837-2001e1 Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method《用钻孔应变仪法测定残余应力的标准试验方法》.pdf》由会员分享，可在线阅读，更多相关《ASTM E837-2001e1 Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method《用钻孔应变仪法测定残余应力的标准试验方法》.pdf（10页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: E 837 01e1Standard Test Method forDetermining Residual Stresses by the Hole-Drilling Strain-Gage Method1This standard is issued under the fixed designation E 837; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea

2、r of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTE Equations 17 and 18, Sections 9.2.2, 9.2.3, 11.2.5 , 11.2.6 and Table 2 were editorially upated in January 2002.INTRO

3、DUCTIONThe hole-drilling strain-gage method measures residual stresses near the surface of a material. Themethod involves attaching strain gages to the surface, drilling a hole in the vicinity of the gages, andmeasuring the relieved strains. The measured strains are then related to relieved principa

4、l stressesthrough a series of equations.1. Scope1.1 This test method covers the procedure for determiningresidual stresses near the surface of isotropic linearly-elasticmaterials. Although the concept is quite general, the testmethod described here is applicable in those cases where thestresses do n

5、ot vary significantly with depth and do not exceedone half of the yield strength. The test method is oftendescribed as “semi-destructive” because the damage that itcauses is very localized and in many cases does not signifi-cantly affect the usefulness of the specimen. In contrast, mostother mechani

6、cal methods for measuring residual stress sub-stantially destroy the specimen. Since the test method de-scribed here does cause some damage, it should be appliedonly in those cases either where the specimen is expendable orwhere the introduction of a small shallow hole will notsignificantly affect t

7、he usefulness of the specimen.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitation

8、s prior to use.2. Referenced Documents2.1 ASTM Standards:E 251 Test Methods for Performance Characteristics ofMetallic Bonded Resistance Strain Gages23. Summary of Test Method3.1 A strain gage rosette with three or more elements of thegeneral type schematically illustrated in Fig. 1 is placed in the

9、area under consideration. The numbering scheme for the straingages follows a clockwise (CW) convention (1).3NOTE 1The gage numbering convention used for the rosette illus-trated in Fig. 1 differs from the counter-clockwise (CCW) convention usedfor some designs of general-purpose strain gage rosettes

10、 and for someother types of residual stress rosette. If a strain gage rosette with CCWgage numbering is used, the residual stress calculation methods describedin this test method still apply. The only change is a reversal in theassignment of the direction of the most tensile principal stress. Thisch

11、ange is described in Note 7. All other aspects of the residual stresscalculation are unaffected.3.2 A hole is drilled at the geometric center of the straingage rosette to a depth of about 0.4 of the mean diameter of thestrain gage circle, D.3.2.1 The residual stresses in the area surrounding thedril

12、led hole relax. The relieved strains are measured with asuitable strain-recording instrument. Within the close vicinityof the hole, the relief is nearly complete when the depth of thedrilled hole approaches 0.4 of the mean diameter of the straingage circle, D.1This test method is under the jurisdict

13、ion of ASTM Committee E28 onMechanical Testing and is the direct responsibility of Subcommittee E28.13 onResidual Stress Measurement.Current edition approved Oct. 10, 2001. Published November 2001. Originallypublished as E 837 81. Last previous edition E 837 99.2Annual Book of ASTM Standards, Vol 03

14、.01.3The boldface numbers in parentheses refer to the list of references at the end ofthis test method.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.3 Fig. 2 shows a schematic representation of the residualstress and a typical su

15、rface strain relieved when a hole is drilledinto a material specimen. The surface strain relief is related tothe relieved principal stresses by the following relationship:er5 A1 Bcos 2b!smax1 A2 Bcos 2b!smin(1)where:er= relieved strain measured by a radially alignedstrain gage centered at P,A,B= cal

16、ibration constants,smax= maximum (most tensile) andsmin= minimum (most compressive) principal stressespresent at the hole location before drilling,b = angle measured clockwise from the direction ofgage 1 to the direction of smax,D = diameter of the gage circle,D0= diameter of the drilled hole.3.3.1

17、The following equations may be used to evaluate theconstants Aand Bfor a material with given elastic properties:A5 a 11v! / 2E! (2)B5 b/ 2E! (3)where:E = Youngs modulus,FIG. 1 Schematic Diagram Showing the Geometry of a Typical Three-Element Clockwise (CW) Strain Gage Rosette for the Hole-DrillingMe

18、thodFIG. 2 Definitions of SymbolsE83701e12v = Poissons ratio, anda and b are dimensionless, almost material-independentconstants (see Note 2). Slightly different values of theseconstants apply for a through-thickness hole made in a thinspecimen and for a blind hole made in a thick specimen. Thenumer

19、ical values of these constants are provided in this testmethod.NOTE 2The dimensionless coefficients a and b vary with hole depth,as indicated in Table 1. They are both nearly material-independent. Theydo not depend on Youngs modulus, E, and they vary by less than 1 % forPoissons ratios in the range

20、0.28 to 0.33. For a through-hole in a thinplate, a is independent of Poissons ratio.3.3.2 The relieved strains e1, e2, and e3are measured bythree correspondingly numbered strain gages as shown in Fig.1. For specialized applications, a rosette with three pairs ofstrain gages arranged in directions1-2

21、-3maybeused (see5.2.3). Measurement of these three relieved strains providessufficient information to calculate the principal stresses smaxand sminand their orientation b.3.3.3 For reasons of pictorial clarity in Fig. 2, the principalresidual stresses smaxand sminare shown as uniformly actingover th

22、e entire region around the hole location. In actuality, itis not necessary for the residual stresses to be uniform oversuch a large region.The relieved surface strains depend only onthe principal stresses that originally existed at the boundaries ofthe hole (2). The stresses beyond the hole boundari

23、es do notaffect the relieved strains. Because of this, the hole-drillingmethod provides a very localized measurement of residualstresses.3.3.4 It is assumed that the variations of the original stresseswithin the boundaries of the hole are small and that thevariation with depth is negligible. It is n

24、ot necessary for theoriginal stresses outside of the hole location to be uniform.4. Significance and Use4.1 Residual stresses are present in almost all structures.They may be present as a result of manufacturing processes orthey may occur during the life of the structure. In many casesresidual stres

25、ses are a major factor in the failure of a structure,particularly one subjected to alternating service loads orcorrosive environments. Residual stress may also be beneficialTABLE 1 Numerical Values of Coefficients a and bRosette A abBlind hole Hole Diameter, D0/D Hole Diameter, D0/DDepth/D 0.30 0.35

26、 0.40 0.45 0.50 0.30 0.35 0.40 0.45 0.500.00 .000 .000 .000 .000 .000 .000 .000 .000 .000 .0000.05 .027 .037 .049 .063 .080 .051 .069 .090 .113 .1400.10 .059 .081 .108 .138 .176 .118 .159 .206 .255 .3170.15 .085 .115 .151 .192 .238 .180 .239 .305 .375 .4530.20 .101 .137 .177 .223 .273 .227 .299 .377

27、 .459 .5450.25 .110 .147 .190 .238 .288 .259 .339 .425 .513 .6030.30 .113 .151 .195 .243 .293 .279 .364 .454 .546 .6380.35 .113 .151 .195 .242 .292 .292 .379 .472 .566 .6570.40 .111 .149 .192 .239 .289 .297 .387 .482 .576 .668Through Hole .090 .122 .160 .203 .249 .288 .377 .470 .562 .651Rosette B ab

28、Blind Hole Hole Diameter, D0/D Hole Diameter, D0/DDepth/D 0.30 0.35 0.40 0.45 0.50 0.30 0.35 0.40 0.45 0.500.00 .000 .000 .000 .000 .000 .000 .000 .000 .000 .0000.05 .029 .039 .053 .068 .086 .058 .078 .102 .127 .1570.10 .063 .087 .116 .148 .189 .134 .179 .231 .286 .3550.15 .090 .123 .162 .205 .254 .

29、203 .269 .343 .419 .5040.20 .107 .145 .189 .236 .289 .256 .336 .423 .511 .6050.25 .116 .156 .202 .251 .305 .292 .381 .476 .571 .6680.30 .120 .160 .206 .256 .309 .315 .410 .509 .609 .7070.35 .120 .160 .206 .256 .308 .330 .427 .529 .631 .7300.40 .118 .158 .203 .253 .305 .337 .437 .541 .644 .743Through

30、 Hole .096 .131 .171 .216 .265 .329 .428 .531 .630 .725Rosette C abBlind Hole Hole Diameter, D0/D Hole Diameter, D0/DDepth/D 0.40 0.45 0.50 0.55 0.60 0.40 0.45 0.50 0.55 0.600.00 .000 .000 .000 .000 .000 .000 .000 .000 .000 .0000.05 .065 .084 .106 .130 .157 .105 .132 .158 .185 .2170.10 .147 .191 .23

31、8 .293 .361 .250 .314 .373 .440 .5190.15 .218 .281 .347 .420 .506 .391 .484 .570 .658 .7540.20 .270 .343 .421 .504 .595 .506 .617 .719 .816 .9120.25 .302 .381 .465 .554 .648 .591 .712 .823 .923 1.0150.30 .321 .403 .491 .583 .679 .650 .778 .893 .994 1.0810.35 .331 .415 .505 .599 .698 .690 .822 .939 1

32、.041 1.1250.40 .336 .421 .512 .608 .709 .719 .851 .970 1.073 1.154Through Hole .316 .399 .494 .597 .707 .623 .723 .799 .847 .859E83701e13as, for example, compressive stresses produced by shot peen-ing. The hole-drilling strain-gage technique is a practicalmethod for determining residual stresses. Se

33、e Table 1.5. Strain Gages5.1 A rosette comprising three single or pairs of strain gagegrids shall be used.NOTE 3It is recommended that the gages be calibrated in accordancewith Test Methods E 251.5.1.1 The gages shall be arranged in a circular pattern,equidistant from the center of the rosette.5.1.2

34、 The principal gage axes shall be oriented in each ofthree directions, (1) a reference direction, (2) 45 or 135 to thereference direction, and (3) perpendicular to the referencedirection. Direction (2) bisects directions (1) and (3), (see Fig.1).5.2 Several different standardized rosettes are availa

35、ble tomeet a wide range of residual stress measurement needs.4Fig.3 shows three different rosette types.5.2.1 Fig. 3 (a) shows the type A rosette, first introduced byRendleer and Vigness (3). This pattern is available in severaldifferent sizes, and is recommended for general-purpose use.5.2.2 Fig. 3

36、 (b) shows thr type B rosette. This pattern has allstrain gage grids located on one side. It is useful wheremeasurements need to be made near an obstacle.5.2.3 Fig. 3 (c) shows the type C rosette. This special-purpose pattern has three pairs of opposite strain gage gridsthat are to be connected as t

37、hree half-bridges. It is useful wherelarge strain sensitivity and high thermal stability are required(19).NOTE 4Standardized hole-drilling rosette patterns were first proposedby Rendler and Vigness (3). The use of standardized rosette designsgreatly simplifies the calculation of the residual stresse

38、s.5.3 The center of the gage circle shall be clearly identifiableboth before and after the drilling operation.5.4 The application of the strain gage (cementing, wiring,protective coating) shall closely follow the manufacturersrecommendations, and shall ensure the protection of the straingage grid du

39、ring the drilling operation.5.5 The strain gages shall remain permanently connectedand the stability of the installation shall be verified. A resis-tance to ground of at least 20 000 MV is preferable.6. Instrumentation6.1 The instrumentation for recording of strains shall have astrain resolution of

40、62 3 106, and stability and repeatabilityof the measurement shall be at least6 2 3 106. The lead wiresfrom each gage should be as short as practicable and athree-wire temperature-compensating circuit (4) should beused with rosette types A and B. Half-bridge circuits should beused with rosette type C

41、, the resulting outputs of which aredesignated e1, e2, and e3.4Strain gage patterns of these designs are manufactured by MeasurementsGroup, Wendell, NC.FIG. 3 Hole-Drilling RosettesE83701e14NOTE 5In general, surface preparation should be restricted to thosemethods which have been demonstrated to ind

42、uce no significant residualsurface stresses.7. Specimen Preparation7.1 The surface preparation prior to cementing the straingage shall conform to the recommendations of the manufac-turer of the cement used to attach the strain gage.7.1.1 A thorough cleaning and degreasing is required.7.1.2 A smooth

43、surface is usually necessary for strain gageapplication. However, abrading or grinding that could appre-ciably alter the surface stresses must be avoided.8. Procedure8.1 Drilling:8.1.1 To protect the strain gage grids, a margin of at least0.012 in. (0.30 mm) should be allowed between the holeboundar

44、y and the end loops of the strain gage grids. The needfor this margin limits the maximum allowable diameter, D0ofthe drilled hole. The minimum recommended hole diameter is60 % of the maximum allowable diameter. Table 2 lists therecommended hole diameter ranges for several common straingage rosette t

45、ypes.NOTE 6As the ratio D0/ D increases, the sensitivity of the methodincreases in approximate proportion to (D0/ D)2. In general, larger holesare recommended because of the increased sensitivity.8.1.2 The center of the drilled hole shall coincide with thecenter of the strain gage circle to within e

46、ither 60.004 D or60.001 in. (60.025 mm), whichever is greater. Errors due tomisalignment of the drilled hole could produce significanterrors in the calculated stress. To avoid these errors, it isrecommended that an optical device be used for centering thetool holder. A device suitable for this is sh

47、own in Fig. 4.58.1.3 Select the drilling operation and tool to minimize oreliminate the introduction of plastic deformation in the areasurrounding the drilled hole.8.1.3.1 Several drilling techniques have been investigatedand reported to be suitable for the hole drilling method:(1) Abrasive jet mach

48、ining,6a method for hole drilling inwhich a high-velocity stream of air containing fine abrasiveparticles is directed against the workpiece through a small-diameter nozzle, has been used successfully (5, 6). However,this technique may not be suitable for softer materials such ascopper (7).(2) Drilli

49、ng at very high speed (up to 400 000 rpm) with anair turbine has also been used successfully in this application(8). This technique is believed to be generally suitable exceptfor extremely hard materials such as stellite (7).(3) End mills, carbide drills, and modified end mills havebeen used successfully in a number of studies (3, 9, 10, 11).Itappears, however, that low-speed drilling with an end mill maybe less suitable than abrasive jet machining or high-speeddrilling (7).Since any residual stress created by the selected drillingm