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  are rewritten to both add to the available technology for uncertainty analysis and to make it easier for.
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Standard statistical hypothesis testing may be used to evaluate the significance of the difference observed.
This simple step, often overlooked, is o essential to successfully develop and apply the uncertainty information. The use of back-to-back tests is an excellent method to reduce the systematic standard uncertainty when comparing two or more designs.
It is assumed that these estimates are based on. By comparing known input values with their mea- is the testing of a gas turbine engine in an altitude sured results, estimates of the data acquisition facility. Comparison 191 the previously reported test result with the more ase value determined by eq. That ptv, z R p f X1, X2.
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 .
Uncertainties in Absolute Terms Example In this wexample we will consider a round tube so A p The Mach number for this flow is well below 0.
ASME PTC 19.1-2005 试验不确定度 Test Uncertainty.pdf
Another situation where previous values of a variable would be useful is when a small sample size N is used to calculate the mean value X of a measurement. Depending on whether common instrumentation, setups, and calibrations are used between comparative tests, the effects of correlated uncertainties see Section 8 may cause 19. total uncertainty of the difference between the test results to be less than the uncertainty of each separate test result.
However, for test measurements involving a single calibration i.
These additional uncertainties may be of either a systematic or random nature depending on their effect on the measurement. Therefore, UXi is a combination of variances: Typically, w these error distributions are assumed Gaussian normally distributed or rectangular uniformly distributed.
The statistics from repeated tests allow for quantifying the expected variation in a parameter or in a result derived from parameters. At low Reynolds numbers, the flow is laminar and has a parabolic velocity profile. This section provides an overview of how the measurement process should be defined.
Flow rate can be calculated by making the measurements required to define the independent variables found in eq.
Participation by federal agency representative s or person s affiliated with industry is not to be interpreted as government or industry endorsement of this code or standard. The tainty due to the systematic error of the average experiment lasted a total of 30 min. The approach will be to relate the deviations otc in r X1, X2.
ASME PTC – Test Uncertainty
For the z practicing engineer, this harmonization means the elimination of such ambiguous terms as bias, precision, bias limit, and precision index. The American Society of Mechani- cal Engineers; Friedman, Vice Chair S. The parameters and results are displayed using a relative basis for the uncertainties and sensitivities in Tables The necessary values for pa- first step is to define the individual systematic rameter sensitivity, systematic standard uncertain- and random standard uncertainties 1.1 the mean ties, random standard uncertainties, awme combined in terms of their relative individual percentage standard uncertainty are summarized in the follow- contributions to the combined standard uncertainty ing table.
The difference between ;tc two test results was compared to the previously reported uncertainty to illustrate the asje of applying all known engineering corrections and using appropriate engineering relationships as part of the results analysis process. Example adapted from : The guarded hot plate is used because it is relatively inexpensive and effective in providing the boundary conditions necessary to ensure one dimensional heat flow through the material.
As the difference between the two measurements increases, the overlap region shrinks. This case is called a single test result. The uncertainty model requires estimates of the uncertainties for each of.
The test design should be tailored to the specific situation.