ASME PTC 19.1 TEST UNCERTAINTY PDF
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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The test design should be tailored to the specific situation.
The American Society of Mechanical Engi. In general, correlated systematic standard uncer- wtainties can either decrease, increase, or have no experimental variables. The uncertainty of this mean velocity would be calculated by considering it to be a determined result. The uncertainty due to the random error of the average temperature measurement is evaluated as follows.
If uncertaimty each of the N 19. of the variable X the output of an elemental component is averaged Nk times to w obtain Xk, then the method in para. The uncer- water bath that is being used uncertaint an experiment. Rabensteine, Environmental Systems Corp. International Or- ganization for Standardization; The covariance terms in eq. Elemental errors are classified as random if they wadd scatter to a result. The advantages of utilizing the weighting fx techniques described in this section are that the uncertainty associated with a weighted test result will usually be less than the uncertainty of the results determined from each ucertainty the independent z methods by themselves.
The effect of the oily air can influ- wence the quoted rating of the unit. The traverse points are located at the centroid of 19. areas so that the integrated-average velocity in the pipe is approximated by the average of the velocities determined at the traverse points. It is calculated as: Process stability is estimated from observations of scatter within a data set and is treated as a random error. In this case, the largest contributor is the systematic uncertainty in the discharge coefficient, C.
As discussed in para.
ASME PTC 试验不确定度 Test -电源技术相关资料下载-EEWORLD下载中心
Suppose a thermocouple is being used to measure the temperature of a gas stream, but the user of the thermocouple believes there may be a tendency for the thermocouple to provide a temperature reading that is lower than the actual gas temperature due to a radiative heat transfer mechanism. 119.1 this point characteristic may be useful for other purposes, it raises a problem in determining performance level. Those evaluated with statistical methods are classified as Type A, while those, which are evaluated by other means, are classified as Type B.
X and sX are statistics. Whereas these influences might normally be considered systematic errors during repeated tests, the duplicated tests can randomize these systematic errors providing error estimates from the statistical variations in the combined data pool .
The systematic values were evaluated and are listed in Table 2. Association, 65, December, The stability of a measurement method is a generic concept related to the closeness of agreement between test results.
The Pitot tube, digital pressure transmitter, and DAS are calibrated together as a system. This procedure should be repeated for all remaining data points.
Engineers have come to appreciate that few things in life are known exactly. Consider a burst test for an improved container design. The effect on the curve-fit is to shift it to the right or left depending on the sign of the errors the signs and magnitudes of the errors are unknown. In this case, uncertqinty following procedure should be employed for constructing a nonsymmetric uncertainty interval for the unknown true value of the quantity being measured see Fig.
The uncertainty model requires estimates of the uncertainties for each of. The following comments are offered to serve as a guide to the engineer in this process.
If there is not valid engineering justifica- tion to remove the suspected outliers and if removal of the outliers will significantly change the test result and its associated uncertainty, the validity of the test should be questioned.
The absolute systematic standard uncertainty, bP, associated with each gage is 3, Pa. Applied Numerical Methods for Digital Computation, 3rd edition. Velocity is measured at each point with the same Pitot tube, digital pres- fx sure transmitter, and DAS. The general form of the expression for determining the uncertainty of a measurement is the rootsum-square of the systematic and random standard uncertainties of the measurement, with this quantity defined as the combined standard uncertainty uX .
The effect of the propa- gation can be approximated by the Taylor series method see Nonmandatory Appendix C.
Cases are considered where Xnew has systematic w standard uncertainty which is correlated with that in Xj and where Xnew has systematic standard wuncertainty which is not correlated with that in Xj.
A simple illustration of the impact of spatial variation is the measurement of average velocity in fully developed flow of an incompressible fluid in a pipe. It is a more general fx version of the central limit theorem than what www. This uncertainty of method is sometimes referred to as uncertainty sV 1 0.
ASME PTC – Test Uncertainty
The suspected outliers should then be subjected to an engineering analysis. The effort to update the revision tset immediately upon completion of that docu. The results from each of the independent laboratories each de- termined as an offset to be applied to the instrument w when measuring a specific input level are used as input to eq. A statistical technique called In this case, some of the parameters may be based analysis of variance ANOVA is useful for parti- on single measurements and others may be the tioning the total variance by source.
ASME PTC 19.1-2005 试验不确定度 Test Uncertainty.pdf
Variability in independent test results obtained under different test conditions, varying experimental setups, or configuration changes allow for additional between-test random errors. Flowmeters 1, 2, 3, and 4 Calibrated Against the Same Standard. This calibration standard uncertainty is treated as a fully correlated standard uncertainty associated with the pressure gage.
Uncertainties in Relative Terms for the Uncalibrated Case. Standard protocol is to bring a replacement gage uncertainyy the test location on the day of the test and replace the gage just prior to the test. Its use for such comparisons is than the other two intervals, but that the relative especially appropriate when it kncertainty reasonable to sizes of the tolerance and prediction intervals de- assume that each of the competing processes has pend upon the proportion of the population to the same statistical variability as measured by the be ase in the prediction interval.
A second example cation the inlet pressure is elevated due to the ram drag effects of the aircraft. The sample standard deviation asmf each point is summarized in Table Several simplifying assumptions are made for this example: