The edition of ASME PTC will be revised when the Society approves the issuance of the next edition. There will be no Addenda issued to ASME PTC. ASME PTC Test Uncertainty [ASME] on *FREE* shipping on qualifying offers. The scope of this Code is to specify procedures for . (Revision of ASME PTC ). Test Uncertainty. Performance Test Codes. AN AMERICAN NATIONAL STANDARD. Two Park Avenue • New York, NY.
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In many cases, the antici- pated representation of the data is a straight line, or a simple first-order linear regression. The time interval must be clearly specified to classify an error, and it may not always be the same interval as the test duration.
A quick and easy way to numerically calculate the sensitivity coefficients of the independent m parameters is ame develop a table using a spread- sheet program on the personal computer. This means that the odds against rejecting a uncertaint point are 20 to 1 or less. The results of these past tests were used to compute a standard deviation representing the dispersion of errors differences in average pipe velocities computed using 20 traverse points along each of the 4 radii versus those obtained using 10 traverse points.
The Amer-  Steele, W. This term, too, was included in this Supplement for improved harmony with international guidelines and standards. Using the uncertainty model and associated assumptions presented in subsectionexpressions for the uncertsinty percentage contributions from elemental sources of standard uncertainty were derived and are presented below.
ASME PTC 试验不确定度 Test -电源技术相关资料下载-EEWORLD下载中心
It is quite common for an experimental o result, r X1, X2. An example is the testing of an automotive engine. In some cases, elemental systematic standard uncertainties may arise from the same elemental error source and are therefore correlated. The as- discuss tolerance intervals, but make no mention of sumption of equal standard deviations is fre- prediction intervals except in a regression context. The results from each of the independent laboratories each de- termined as an offset to be applied to the instrument w when measuring a yest input level are used as input to eq.
In order to obtain the overall uncertainty in the m result, UR, at a specified confidence level, the ISO Guide recommends that the combined standard uncertainty of the result be multiplied by a cover- o age factor.
A correction factor must be applied that corrects between uninstalled to installed aircraft engine performance. The same is true for the Xj z data points.
Difference hncertainty results from. The Pitot tube, digital pressure transmitter, and DAS are calibrated together as a system.
The effects of a time interval may also be important when considering the stability and control of a test process. Velocity is measured at each point with the same Pitot tube, digital pres- fx sure transmitter, and DAS.
The elemental systematic sources. The statistics found by combining these duplicated data sets allow for a reasonable estimate of the variations possible in the result that might be due to the control of test operating conditions, or use of different test rigs, instrumentation, or test location.
The American Society of Mechanical Engineers; Circumferential variations may also be present. For small degrees uncertaint freedom, see Nonmandatory Appendix B.
In general, increasing the number of measurements collected during a test and used in the preceding formulas is beneficial as w a it improves the sample mean as an estimator of asmw true population mean; b it improves the sample standard deviation as an estimator of the true population standard devia- w tion; and c it typically reduces the value of the random wstandard uncertainty of the sample mean. In a sample of measurements, the degrees of freedom is the sample size N.
The last or For this example, the velocity is measured at 40 unique traverse points 10 traverse positions along 4 equally spaced radii corresponding to the z centroid of equal areas as shown in Fig. The value used is called the assigned value. Because of the resulting effect of combining the elemental uncertainties in a root-sum-square manner, the larger or dominant ones will control.
ASME PTC 19.1-2005 试验不确定度 Test Uncertainty.pdf
Each additional level in the calibration hierarchy adds uncertainty in the measurement process see Fig. The standard deviation published from these past tests was assumed to be representative of the systematic standard uncertainty for the present test resulting from spatial variation in the radial direction. The results of this analysis are summarized in Table The systematic standard uncertainty of the measurement is the root-sum-square of the elemental systematic standard uncertainties bXk for all sources.
An additional systematic standard uncertainty uncertainry need to be assigned to the mean result to account for the possible difference between the determined mean and the true mean. As the difference between ucertainty two measurements increases, the overlap region shrinks. Therefore, the uncer- recognize that the numerical average may not tainty due uncegtainty spatial variation must be inferred equal the integrated-average value over the entire from available data.
Additionally, a pretest uncertainty analysis facilitates communication between all parties to the test about the expected quality of the test.