共查询到19条相似文献,搜索用时 140 毫秒
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申请实验室用示值误差优于2″的测量角仪对角度块的示值A1进行测量,分析测量过程中测量重复性、光学瞄准、仪器误差等影响,得到示值误差的测量不确定度U1(k=2);参考实验室用多齿轮分度台对角度块的示值A2进行测量,评估测量过程的不确定度来源,得到示值误差的测量不确定度U2(k =2);用公式计算得到示值误差测量审核的En值为0.4,角度块示值误差的测量审核的结果为满意. 相似文献
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角度块是一种精密的角度量具,常用来检定万能角度尺和角度样板,也可用于加工中的角度调整。现行检定规程描述角度块角值的测量方法是用测角仪,文章是针对用带细分装置的多齿分度台与自准直仪组合来测量角度块角值。根据测量原理,建立数学模型,分析测量中的瞄准误差、测量重复性、仪器示值误差等各种影响因素,评定出角度块角值测量的扩展不确定度,仪确定带细分装置的多齿分度台是否可作为标准器,进行1、2级角度块角值的测量。 相似文献
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介绍了一种由程控型多齿分度台和高精度圆度仪组合而成的全自动误差分离装置,该装置能够使圆度仪主轴回转误差从被测工件测量结果中可靠分离,从而极大地提高了圆度测量不确定度,本文对该装置测量不确定度进行了分析。 相似文献
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基于非正交轴系全站仪坐标测量系统的结构特点和测量模型,用数学分析的手段对其进行误差分析和测量不确定度评定。确定系统的主要误差分量是转台旋转角误差和激光跟踪仪测距值误差,并用GUM法评定各分量的不确定度。通过测量模型推导出系统的测量不确定度,并用MATLAB进行仿真,结果表明:当测距值不变时,测量不确定度几乎不受水平角变化的影响,而随着垂直角绝对值的增大而增大,当角度值不变时,测量不确定度随着被测点到视准轴上标定点的距离值增大而增大。实验初步验证了仿真结果的准确性。 相似文献
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传统的气动弹性系统颤振分析模型大多是在确定性参数条件下建立的,当系统中存在不确定因素时,按确定性方法设计的气动弹性系统存在颤振失效风险.以概率和非概率区间模型为基础,建立了单源不确定性条件下颤振可靠性分析模型;在此基础上,针对含随机和区间多源不确定参数的气动弹性系统颤振可靠性分析问题,提出一种基于分步求解策略的新型混合... 相似文献
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This paper presents a methodology for uncertainty quantification and model validation in fatigue crack growth analysis. Several models – finite element model, crack growth model, surrogate model, etc. – are connected through a Bayes network that aids in model calibration, uncertainty quantification, and model validation. Three types of uncertainty are included in both uncertainty quantification and model validation: (1) natural variability in loading and material properties; (2) data uncertainty due to measurement errors, sparse data, and different inspection results (crack not detected, crack detected but size not measured, and crack detected with size measurement); and (3) modeling uncertainty and errors during crack growth analysis, numerical approximations, and finite element discretization. Global sensitivity analysis is used to quantify the contribution of each source of uncertainty to the overall prediction uncertainty and to identify the important parameters that need to be calibrated. Bayesian hypothesis testing is used for model validation and the Bayes factor metric is used to quantify the confidence in the model prediction. The proposed methodology is illustrated using a numerical example of surface cracking in a cylindrical component. 相似文献
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Uncertainty modelling of atmospheric dispersion by stochastic response surface method under aleatory and epistemic uncertainties 总被引:1,自引:0,他引:1
The parameters associated to a environmental dispersion model may include different kinds of variability, imprecision and uncertainty. More often, it is seen that available information is interpreted in probabilistic sense. Probability theory is a well-established theory to measure such kind of variability. However, not all available information, data or model parameters affected by variability, imprecision and uncertainty, can be handled by traditional probability theory. Uncertainty or imprecision may occur due to incomplete information or data, measurement error or data obtained from expert judgement or subjective interpretation of available data or information. Thus for model parameters, data may be affected by subjective uncertainty. Traditional probability theory is inappropriate to represent subjective uncertainty. Possibility theory is used as a tool to describe parameters with insufficient knowledge. Based on the polynomial chaos expansion, stochastic response surface method has been utilized in this article for the uncertainty propagation of atmospheric dispersion model under consideration of both probabilistic and possibility information. The proposed method has been demonstrated through a hypothetical case study of atmospheric dispersion. 相似文献
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测量不确定度直接评定法和综合评定法的几个典型实例第一讲直接评定法及其实例 总被引:1,自引:0,他引:1
王承忠 《理化检验(物理分册)》2006,42(4):210-215
采用直接评定法评定了带肋钢筋拉伸性能、金属材料维氏硬度检测结果的测量不确定度,用综合评定法评定了金属材料夏比缺口冲击试验、洛氏硬度检测结果的不确定度。结果表明,综合评定法在这些典型实例中解决了金属材料理化检测结果测量不确定度评定的某些难点。 相似文献
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测角仪是角度计量常用的仪器。高准确度的测角仪一般作为角度计量标准器使用。由于没有更高准确度的计量标准进行测角仪的检定,根据圆分度闭合即各相邻间隔分度误差的总和为零原理,采用全组合比较或常角对称联系法测量测角仪的分度误差。最新修订的测角仪检定规程(JJG97-2001)规定了1″级测角仪在首次检定或要对度盘进行修正时采用常角排列互比对称联系法,后续检定时采用23面棱体排列互比法检定。本文分别对两方法测量不确定度进行了评定,评定结果其不确定度均优于0.1″。 相似文献
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