Evaluation on Measurement Uncertainty of Plasticity Strain Ratio of Metallic Sheet

The testing methods was used to evaluate measurement uncertainty of plasticity stress ratio r values,the uncertainty factors such as specimen dimension measurement and extensometer were discussed and calculated. It was indicated that,when the combined uncertainty was evaluated,the sensitivity coefficient of each uncertainly weight variables should be calculated by plastic stress ratio r value equation;when the input quantities were apparent correlative,the effect of correlation coefficient should be take into account in equation.