1、Designation: F 2274 03An American National StandardStandard Specification forCondition 3 Bicycle Forks1This standard is issued under the fixed designation F 2274; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This standard establishes testing requirements for quali-fying designs using production forks intended for use inCondition 3
3、per Classification F 2043.1.2 This standard is applicable to suspension and non-suspension bicycle forks for use of a bicycle on rough trails,rough unpaved roads, and rough technical areas and unim-proved trails. Contact with irregular terrain and momentaryloss of tire contact with the ground may oc
4、cur during usage.This usage is referred to as Condition 3 per ClassificationF 2043. Other types of bicycle uses exist and other specifica-tion standards will apply for uses other than Condition 3.2. Referenced Documents2.1 ASTM Standards:2E 739 Practice for Statistical Analysis of Linear or Linear-i
5、zed Stress-Life ( S-N) and Strain-Life (e-N) Fatigue DataF 2043 Classification for Bicycle UsageF 2273 Test Methods for Bicycle Forks3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 confidenceas used in this standard, is defined as aprobability that the population value for eit
6、her the mean orstandard deviation lies within a particular interval determinedbased on the desired probability and the sample size.4. Classification4.1 Condition 3 per Classification F 2043.5. Sampling and Test Specimens5.1 Selection and Preparation of Specimens:5.1.1 Five forks shall be randomly se
7、lected from the firstproduction lot for the fatigue test per this test method.5.1.2 Three forks shall be randomly selected from the firstproduction lot for the impact test per this test method.5.1.3 One fork shall be randomly selected from the firstproduction lot for both the compression and bending
8、 tests perthis test method.6. Performance Requirements6.1 Bicycle forks intended by the manufacturer to be usedaccording to Condition 3 shall be tested per Test MethodsF 2273.6.1.1 Compression Load Test:6.1.1.1 The fork shall withstand a compression load of 2800N without any component failure, fract
9、ure or permanentdeformation.6.1.1.2 Under the application of the compression load of2800 N, the minimum clearance from the maximum tire profileintended for use by the manufacturer to the nearest surface ofthe crown shall be at least 3 mm.6.1.2 Bending Load Test:6.1.2.1 The fork shall withstand a max
10、imum bending loadof 1500 N (100 N initial load plus an additional 1400 N).6.1.2.2 The permanent deflection of a rigid fork shall notexceed 5 mm and the permanent deflection of a suspension forkshall not exceed 10 mm.6.1.3 Impact Resistance Test:6.1.3.1 For each fork, permanent deflection shall be le
11、ssthan 45 mm following impact of a 22.5 kg mass dropped fromheight number 1 such that the velocity at impact shall be atleast 2.66 m/s. Note that in a frictionless system, this velocitywould be achieved for height number 1 of 360 mm.6.1.3.2 For each fork, following impact of a 22.5 kg massdropped fr
12、om height number 2 such that the velocity at impactshall be at least 3.43 m/s, the connection between the steerertube and crown must withstand at least 108.5 Nm of torquewithout rotation. Note that in a frictionless system, this velocitywould be achieved for height number 2 of 600 mm.6.1.4 Fatigue T
13、est:6.1.4.1 Each fork shall withstand a fully reversed sinusoidalload of 750 N for at least 50 000 cycles without failure.6.1.4.2 Using the lower 90 percent confidence limit on themean and the upper 90 percent confidence limit on the standarddeviation, the computed number of cycles that includes 90p
14、ercent of the area under the fatigue life distribution deter-mined using these confidence limits must exceed 20 000. Incomputing the number of cycles that includes 90 percent of thearea under the fatigue life distribution, the measured number of1This specification is under the jurisdiction of ASTM C
15、ommittee F08 on SportsEquipment and Facilities and is the direct responsibility of Subcommittee F08.10 onBicycles.Current edition approved May 10, 2003. Published July 2003.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For A
16、nnual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.cycles to failure is assumed to follow a log-normal distributionper Pract
17、ice E 739. The estimate of the mean is computed fromEq 1 as:x 515(i515xi(1)In Eq 1, where xi= log10ni, where niis the measured numberof cycles to failure for a particular fork. The estimate of thestandard deviation is computed from Eq 2 as:sx5F14(i515xi2 x!2G12(2)In computing the confidence limits,
18、the estimate of the meanis assumed to follow a normal distribution and the estimate ofthe standard deviation is assumed to follow a Chi-squareddistribution. Accordingly, the lower confidence limit on themean is computed from Eq 3 as:LCL 5 x 2 0.953sx(3)and the upper confidence limit on the standard
19、deviation iscomputed from Eq 4 as:UCLs52.372sx(4)With these confidence limits, the log10of the number ofcycles corresponding to 90 % of the area under the fatigue lifedistribution is found from Eq 5:0.9 5*xr LCLUCLs1=2pez22 dz (5)Because the lower limit on this integral is equal to 1.282,the value o
20、f xris given byxr5 LCL 2 1.282 UCLs (6)Finally, the computed number of cycles (N) corresponding to90 % of the area under the fatigue life distribution is foundfrom Eq 7:N 5 10xr(7)The computed value of N must be 20 000.To illustrate this method, consider the following data set:Sample # Cycles (n) Lo
21、g (n)1 168 594 5.2272 93 886 4.9733 63 862 4.8054 81 540 4.9115 78 763 4.896Eq 1 x = 4.962Eq 2 sx= 0.159Eq 3 LCL = 4.811Eq 4 UCLs = 0.378Eq 6 xr= 4.326Eq 7 N = 21 166Result 21 166 20 000So that fork meets the specification for the fatigue test7. Rejection and Rehearing7.1 Fork models that fail to me
22、et the requirements of thisspecification shall be rejected.8. Certification8.1 When specified in the purchase order or contract, areport of the test results shall be furnished pursuant to thereport as described in Test Methods F 2273.9. Keywords9.1 bicycle forks; condition 3; fatigue; impact; load t
23、est;qualifying designsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringeme
24、nt of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or
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26、wn to the ASTM Committee on Standards, 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).F2274032
