1、附录附录1英文原文Reflections regarding uncertainty of measurement, on the results of a Nordic fatigue test interlaboratory comparisonMagnus Holmgren, Thomas Svensson, Erland Johnson, Klas JohanssonAbstract This paper presents the experiences of calculation and reporting uncertainty of measurement in fatigue
2、 testing. Six Nordic laboratories performed fatigue tests on steel specimens. The laboratories also reported their results concerning uncertainty of measurement and how they calculated it. The results show large differences in the way the uncertainties of measurement were calculated and reported. No
3、 laboratory included the most significant uncertainty source, bending stress (due to misalignment of the testing machine, “incorrect” specimens and/or incorrectly mounted specimens), when calculating the uncertainty of measurement. Several laboratories did not calculate the uncertainty of measuremen
4、t in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) 1.Keyword： Uncertainty of measurement, Calculation, Report, Fatigue test, Laboratory intercomparisonDefinitions ：R Stress ratio Fmin/Fmax F Force (nektons) A and B Fatigue strength parameters s and S Stress (megapas
5、cals) N Number of cycles. IntroductionThe correct or best method of calculating and reporting uncertainty of measurement in testing has been the subject of discussion for many years. The issue became even more relevant in connection with the introduction of ISO standards, e.g. ISO17025 2. The discus
6、sion, as well as implementation of the uncertainty of measurement concept, has often been concentrated on which equation to use or on administrative handling of the issue. There has been less interest in the technical problem and how to handle uncertainty of measurement in the actual experimental si
7、tuation, and how to learn from the uncertainty of measurement calculation when improving the experimental technique. One reason for this may be that the accreditation bodies have concentrated on the very existence of uncertainty of measurement calculations for an accredited test method, instead of o
8、n whether the calculations are performed in a sound technical way. The present investigation emphasizes the need for a more technical focus. One testing area where it is difficult to do uncertainty of measurement calculations is fatigue testing. However, there is guidance on how to perform such calc
9、ulations, e.g. in Refs. 3, 4. To investigate how uncertainty of measurement calculations are performed for fatigue tests in real life, UTMIS (the Swedish fatigue network) started an interlaboratory comparison where one of the most essential parts was to calculate and report the uncertainty of measur
10、ement of a typical fatigue test that could have been ordered by a customer of the participating laboratories. For cost reasons, customers often ask for a limited number of test specimens but, at the same time, they request a lot of information about a large portion of the possible stress-life area f
11、rom few cycles (high stresses) to millions of cycles (low stresses) and even run-outs. The way the calculation was made should also be reported. The outcome concerning the uncertainty of measurement from the project is reported in this article.ParticipantsSix Nordic laboratories participated in the
12、interlaboratory comparison: one industrial laboratory, two research institutes, two university laboratories and one laboratory in a consultancy company. Two of the laboratories are accredited for fatigue testing, and a third laboratory is accredited for other tests. Each participant was randomly ass
13、igned a number between 1 and 6, and this notification will be used in the rest of this paper.Experimental procedureThe participants received information about the test specimens (without material data), together with instructions on the way to perform the test and how to report the results.The instr
14、uctions were that tests should be performed as constant load amplitude tests, with R=0.1 at three different stress levels, 460, 430 and 400 Map, with four specimens at each stress level, at a test frequency between 10 and 30 Hz, with a run-out limit at cycles and in a normal laboratory climate ( and
15、 relative humidity). This was considered as a typical customer ordered test.The test results were to be used to calculate estimates of the two fatigue strength parameters, A and B, according to linear regression of the logs and long variables, i.e. The reported result should include both the estimat
16、ed parameters A and B and the uncertainties in them due to measurement errors. The report should also include the considerations and calculations behind the results, especially those concerning uncertainty of measurement.Several properties were to be reported for each specimen. The most important one was the number of cycles until fracture or if the specimen was a run-out (i.e. survived for cycles).The tests were to be performed in
