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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Assuming ideal gas properties for dry air, ideal w gas property tables for air are used to evaluate h1, h2, and h2s. Uncertainhy on the application, vari- w ous confidence levels may be appropriate.
ASME PTC 试验不确定度 Test -电源技术相关资料下载-EEWORLD下载中心
The estimation of the sample mean and standard deviation based on Ni measurements is calculated as described in para. Cases are considered where Xnew has systematic w standard uncertainty which is correlated phc that in Xj and where Xnew has systematic standard wuncertainty which is not correlated with that in Xj.
Specifically, a tolerance interval is applicable if o limits are needed that contain most of the sampled population, while a prediction interval would be used to obtain limits to contain all of a small. This asem, in turn, lead to expression of an uncertainty interval for a test result that does not encompass tets true value. Steele, Vice Chair G. The proposed code or standard was made available for public review and comment that provides an opportunity for additional public input from industry, academia, z regulatory agencies, and the public-at-large.
If the sample standard deviation of the variable being measured is also expected to be representative of other possible random variations in the measurement, e. Examples of error sources include Measurement uncertainty can also exist from imperfect pc corrections, uncontrolled test interactions between a the test instrumentation conditions, measurement methods, environmental and the test media or b between the test article conditions, and data reduction techniques.
The uncertainty interval is composed of both the systematic and random uncertainty components. The second is a table that summarizes the uncertainty information at the result level. A pretest analysis is required to determine if an uncalibrated venturi could be used to satisfy the test objective, and, if not, whether calibration of the venturi would achieve the desired objective.
Furthermore, assume asm the higher order terms in the Taylor series expansion for r are negligible compared to the first order terms. Now suppose an experimental result, r, is wdefined as a function of certain measured variables, C If this can be done then it should be, but tezt not then the method of para.
The necessary values for pa- first step ltc to define the individual systematic rameter sensitivity, systematic standard uncertain- and random standard uncertainties of the mean ties, random standard uncertainties, and combined in terms of their relative individual percentage standard uncertainty are summarized in the follow- contributions to the combined standard uncertainty ing table.
The odds could be increased by setting the probability of rejecting a good data point lower.
The results of this uncertainty analysis are presented in Tables and in which each symbol has the same description as in Table w This procedure should be repeated for all remaining data points. Typically, these larger data sets are taken in the early phases of an experimental program. 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.
Spatial variation effects are considered errors of method see para. The new nomenclature is expected to render PTC It will vary as a function of sample size. The final data reduction equation becomes: Otherwise, these elemental systematic standard uncertainties are combined per subsection The pump design data is presented in Table The table has been developed in accordance with the step-bystep procedure of Section 9.
The results of these calculations are summarized in Table This is known as a prediction interval. Typically, total systematic standard uncertainty is quantified by a identifying all elemental sources of systematic w error for the measurement; b evaluating elemental systematic standard uncertainties as the standard deviations of the possible systematic error distributions; and w c combining the elemental systematic standard uncertainties into an estimate of the total systematic standard uncertainty for the average measurement.
Association, 65, December, The specific value of this statistic must be selected on the basis of the defined confidence level and degrees of freedom associated with the confidence interval. This simple step, often overlooked, is o essential to successfully develop and apply the uncertainty information. In this case, the random and systematic standard uncertainties of the calibration w process should be combined and carried forward as a systematic standard uncertainty.
It is seen that for the given sample of 5, the confidence interval to contain the population w mean is appreciably smaller than both the tolerance interval and the prediction interval. For situations involving other frequency distributions, refer to an appropriate statistics textbook. The effect of outliers is to increase the standard deviation of the system. Repeated Tests When more than one test is conducted with the same instrument package i.
ASME PTC – Test Uncertainty
This code or standard was developed under procedures accredited as meeting the criteria for American National Standards. Uncertainties in Uncertaonty Terms. For example, different Defined Measure- w ment Processes for the same test will result in different estimates of measurement uncertainty. The results from each of the measurement methods each determined as fx an average value over the duration of the test are used as input to eq. Even though the pressure transducer in Program 2 had a systematic standard uncertainty of more than twice those of the transducers in Program 1, the systematic standard uncertainty of the result for Program 2 was less than half of that for Program 1.
ASME PTC 19.1-2005 试验不确定度 Test Uncertainty.pdf
The effects of a time interval may also be important when considering the stability and control of a test process. Errors of this type should not be included as part of the uncertainty of the uncertaintg.
The magnitude has been reduced by having averaged multiple calibrations. The uncer- water bath that is being used in an experiment.
Thus a w more general form of eq. This interval accounts for systematic errors only. 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.