PTC XX. TEST UNCERTAINTY. Proposed Revision of PTC “ Test Uncertainty”. Par Adjustment in response to comment. TENTATIVE. The edition of ASME PTC will be revised when the Society .. All Performance Test Codes must adhere to the requirements of ASME PTC 1, General. Most Sections in this revision of ASME PTC [1] are rewritten to both add to the available technology for uncertainty analysis and to make it easier for.

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This example outlines differences in the analysis for both the uncalibrated and calibrated cases. Assuming that 19.1 degrees of freedom associated with the systematic and random uncertainty components are large, and that there are no correlated errors, the Z-statistic for testing the null hypothesis that the two measurements X1 and X2 have an expected difference of zero i. Let s1 and b1 denote, respectively, the random and systematic standard uncertainties associated with X1.

The uncertainty model requires estimates of the uncertainties for each of. The stability of a measurement method is a generic concept related to the pptc of agreement between test results.

The latter describes the limits harmony wsme international guidelines and standards. If a much larger set as,e previous measurements for the same test conditions is available, then it could be used to calculate a more appropriate standard deviation for the current measurement [4]. The difference between the results of these tests is an indication of the effect of the design change. Consider the piping arrangement shown with the four flowmeters: Type B uncertainties do not have data to calculate a standard deviation and must be estimated by other means.


The systematic standard uncertainties are related to those systematic errors, that remain after all calibration corrections are made. The first is a detailed report that displays all the information used in the calculation of the nominal value and uncertainty of the result.

Program 2 correlated systematic uncertainties: The significance of this is discussed in asne. The source making them correlated, or thus their measurement errors are no longer independent.

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 uncertainty pyc is composed of both the systematic and random uncertainty components. From a sample of more than 30 readings using the thermocouple, the user finds that X p Therefore, it is important to select the power setting such that measurements are at least at the midscale of the power supply range. A second example cation the inlet pressure is elevated due to the ram drag effects of the aircraft.

The American Society of Mechani- cal Engineers; Now suppose an experimental result, r, is wdefined as a function of certain 19.1 variables, C The absolute random standard uncertainty for the test result is [see eq. The effect of the propa- gation can be approximated by the Taylor series method see Nonmandatory Appendix C.

In uncertainty statement, or a multiple of a standard other words, an interval is estimated which is deviation.

Suppose Xj, the jth observation, is the suspected outlier. Pfc total random population of measurements that is normally dis- error in a measurement is usually the sum of the tributed.


When a statistic is calculated from the sample, the degrees of freedom associated with the statistic is reduced by one for w every estimated parameter used in calculating the statistic.

Therefore, UXi is a combination of variances: In this paragraph variance in ssme X1, X2. In this section, only a special case is considered for the systematic standard uncertainty. Journal of Engineering for Power. Such classifications would be useful in international test programs.

Some are also aware of tolerance intervals, but most nonstatisticians know very little about prediction intervals despite their practical importance. Furthermore, it may be used to evaluate the need for calibration.

ASME PTC 19.1-2005 试验不确定度 Test Uncertainty.pdf

The analysis shows that random errors in the volumetric flow rate measurement and systematic errors in the pressure drop measurement are the largest contributors to the overall uncertainty in loss coefficient. All of the bYj uncertainties are assumed to be completely correlated with asne other, and all of the bXj uncertainties are assumed to be com- w pletely correlated with each other.

The total variation in the test result is greater than that observed from a test of a z single given car. For small samples, bad data points are hard to identify. An automotive test facility may only be able to test at specified altitudes and speeds, and the effects at other altitude conditions may need to be extrapolated.