金属薄板塑性应变比（r值）测量不确定度的评定

摘要

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.%　　为评定深冲钢塑性应变比(r值)的测量不确定度,以厚度规格为80 mm的St14试样为例,建立了计算r值不确定度的数学模型,确定了影响r值的各项因素,主要有试样原始宽度及其变形、试样原始标距及其变形4个输入量引入的不确定度和数值修约带入的不确定度,计算出了各因素的标准不确定度,r值的扩展不确定度为0.08,St14试样r值最终测量结果表达式为r=1.84±0.08.