The calculation of the uncertainty in measurement in mechanical testing is a primary step to ensuring the reliability of the results. But even assigning a statistical calculation, not necessarily get a realistic result, as often do not consider all variables that contribute significantly to the uncertainty in measurement and does not consider the effect of the correlation between variables. In this context, the aim of this work is perform an analytical study of the correlation coefficient influence in determining of the uncertainty in measurement of the mechanical strength tensile, obtained by tensile tests. In experimental study varied the number of test specimens to obtain the different values of the correlation coefficient in order to calculate the uncertainty in measurement considering the correlated quantities or not. Through this study it was possible to verify how the correlation between the maximum force and the diameter can influence the measurement result and to present the correct way to calculate the combined uncertainty considering the correlation.
Correlation coefficient; uncertainty in measurement; tensile test
