Evaluation of Uncertainty in Measurement on Plastic Strain Ratio(r Value) of Metallic Sheet
Abstract：In order to evaluate the uncertainty in measurement on plastic strain ratio(r value)of deep drawing steel, making St14 steel of thickness 80 mm as an example, the mathematic model of calculating uncertainty of the r value was established and the factors affecting the r value were determined, which include the uncertainties led into by 4 inputs, that is, original width of simple, the forming in width direction, the original gauge length and its distortion, and taken by rounding off numerical values. The standard uncertainty of each factor was calculated. The expanded uncertainty of the r value is 0.08, and the ultimate expression of measuring result of St14 simple r value is r=1.84±0.08.
Keywords：plastic strain ratio(r value)uncertainty in measurementevaluationexpanded uncertainty
Publication Date：2013-01-01
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)