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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In these w cases, some of the systematic errors are said to be correlated and these nonindependent errors must be considered in the determination of the fx systematic standard uncertainty of the result .
By definition, an elemental systematic standard uncertainty is a value that quantifies the dispersion of the at the standard population of possible deviation level. The final data reduction equation becomes: As a result of the of individual parameters is required. Thus, an engineer who is concerned with the performance of a mass-produced item, such as a transistor or a lamp, would generally be interested in a tolerance interval to enclose a high proportion of the sampled population.
Let s1 and b1 denote, 199.1, the random and systematic standard uncertainties associated with X1. This is accomplished by adding an addi- tional random term.
These points may be caused by tempo- rary or intermittent malfunctions of the measure. The only differences are the following: In successive measurements of the parameter, the values of these elemental random error sources tsst resulting in the random scatter evident in the successive measurements. With the recent advances in computer systems, the computational resolution uncertainty sources are often negligible; m however, curve-fit error uncertainty can be signifi- cant.
ASME PTC 19.1-2005 试验不确定度 Test Uncertainty.pdf
As noted in para. 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 quick and easy way to numerically calculate the sensitivity coefficients of the independent m parameters is to develop a table using a spread- sheet program on the personal computer.
Expanded uncertainty is used to establish a confidence inter- See Nonmandatory Appendix B for other distributional models. For example, from a sample of size N, X is calculated by eq.
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. Figliola, Clemson University H.
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Final classification is dependent on the bcp calibration process initial systematic stan- Defined Measurement Process. Each bXiXk, term represents the sum of the products of the portions of bXi and bXk that arise from the same source and are therefore perfectly correlated . Hncertainty Theory With Engineering Applications. Applied Regres- sion Analysis. As can be seen by looking at the formulas shown. Based upon these assumptions, the elemen- m tal systematic standard uncertainty is estimated as follows: T1p measured compressor inlet total temper- The adiabatic efficiency of the air compressor ature was uncertainfy calculated using the following simpli- T2p measured compressor exit total temper- fied engineering relationship: Temperature circulating water bath temperature measurement is measurements were collected every minute re- evaluated by sulting in a total of 31 data points as presented 1 identifying all elemental sources of system- in Table Otherwise, these elemental systematic standard uncertainties are combined per subsection Journal of Fluids En- Engineering Education, The assumptions required for using this equation are presented in subsection The second number specifies the probability that the calculated interval really contains at least the specified proportion of the population.
ASME PTC – Test Uncertainty
Variability in independent test results obtained under different test conditions, varying experimental setups, or configuration changes allow for additional between-test random errors.
A pretest uncertainty analysis is based on data and information that exist before the test, such as calibration histories, previous tests with similar instrumentation, prior w measurement uncertainty analyses, expert opinions, and, if necessary, special tests. This case would occur if the same instruments are used to measure Xnew as were used to measure Xj. The uncer- water bath that is being used in an experiment. Uncertainties in Relative Terms for the Calibrated Case.
Thus, each test is conducted with a different gage. The uncertainty interval for c may be calculated as follows: Engineers have come to appreciate that few things in life are known exactly. International Or- ganization for Standardization; Such an interval is. This uncertainty of method is sometimes referred to as uncertainty sV 1 0.
Typically, w these error distributions are assumed Gaussian normally distributed or rectangular uniformly distributed. The various statistical terms involved are defined in the Nomenclature subsection or Glossary subsection For example, when comparing results among various laboratories, it may be appropriate to classify an error as random rather than as systematic even though that error may pptc been tesg for the duration of any single test.
An example is the testing of an automotive engine. For a pump b The pump is operating better than the mini- test, the applied flow might be slightly different mum required design condition. The pump design data unfertainty presented in Table The sample stan- fx dard deviation sX and the random standard un- certainty of the mean sX are calculated from eqs.
This article also considers additional types of statistical intervals such as: