桥梁用钢拉伸试验不确定度的评定

Evaluation of Uncertainty of Tensile Test on Bridge Steel

测量不确定度是对测量结果质量的定量表征,测量结果的可用性取决于其不确定度的大小,测量结果必须附有不确定度说明才是完整并有意义的。针对中厚板Q420NHY材料进行了拉伸试验中抗拉强度、下屈服强度、断后伸长率的不确定度评定。结果表明,对于抗拉强度,测量重复性引入的不确定度最为显著,对于下屈服强度,拉伸速率的影响最大,对于断后伸长率测量重复性及断后伸长的测量引入的不确定度最大。在包含概率取95%情况下,抗拉强度、下屈服强度、断后伸长率的扩展不确定度分别为2.4%、2.5%、2.9%。

Measurement of uncertainty is a quantitative characterization of the quality of the measurement results, the availability of the measurement results depends on the size of the uncertainty. The measurement result must be accompanied by instructions of uncertainty to be complete and meaningful. The evaluation of tensile strength, lower yield strength, elongation after fracture uncertainty of tensile test on bridge steel of Q420NHY plate is implemented. The results show that repeatability induced uncertainty is the most significant for tensile strength measurement, tensile rate induced uncertainty is with the greatest impact for lower yield strength; measurement repeatability and elongation measurement induced uncertainty is the maximum for the elongation after fracture uncertainty evaluation. When contain probability is set at 95%, expanded uncertainty of tensile strength, lower yield strength and percentage elongation after fracture are respectively 2.4%, 2.5%, 2.9%.