铝合金拉伸规定塑性延伸强度不确定度评定

Evaluation of Uncertainty of Plastic Elongation Defined by the Tensile Properties of Aluminum Alloy

运用蒙特卡罗方法对铝合金板材拉伸力学性能中的规定塑性延伸强度进行了不确定度评定.除拉力机测量,校准误差,试样尺寸测量误差外,完整引入了引伸计标距,测量误差以及斜率k对不确定度的影响,引入当前GUM法忽略的原点修正的影响.结果表明,不确定最大来源是试样尺寸测量和引伸计引入误差,其次是确定斜率基线误差,和拉力机测量误差;在斜率k较小,斜率与延伸轴的交点距离原点越大,零位修正误差对不确定度的贡献升高.运用Mathematica软件编写了不确定度评定程序.

The application of Monte-carlo method is used to evaluate the uncertainty of the plastic elongation in accordance with the stipulation of the tensile properties of aluminum alloy plates. Besides the tensile machine measurement, calibration deviation, and measured deviation of sample dimension, it has to consider the extensometer gauge length, measurement de- viation, effect of the slope k on the uncertainty, and also the effect of origin correction ignored by the present GUM method. The results show that most of the uncertainty resulted from the measurement of sample dimension and the error of tensile machine, secondary, resulted from the deviations of determining the slope baseline and tensile machine measurement; When the slope k is smaller, the cross point of slope and extending shaft from the origin point will be higher, and the error of zero adjustment will make the uncertainty higher. The Mathematica software is adopted to program the evaluation of uncertainty.