Small punch (SP) method is a promising technique for evaluating tensile properties using small volumes of test material, yet its applicability is bound by large errors in estimation of tensile yield strength (YS) using the yield force (F) determined by the existing two tangent, offset or bilinear function fitting methods. In this study, a yield force (F) based on the occurrence of yielding across the specimen thickness is identified through finite element analysis and a methodology is formulated for determination of F from experimental data, supported with acoustic emission (AE) technique. The YS-F correlation for various structural steels, Inconel and Aluminium exhibit excellent linearity and standard errors within ±7 %. Based on the onset of plastic instability in SP deformation at an inflection point (F, u) of force-deflection curve, the specimen deflection u is shown to correlate with tensile uniform strain better than parameter u (deflection at peak load). The tensile properties of neutron irradiated SS 316 evaluated from SP tests using the methodologies and SP-tensile correlations formulated in this work, are found to be within 6–8 % of the uniaxial tensile test results.

中文翻译：

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用于评估拉伸性能的小冲头变形的改进分析

小冲头 (SP) 方法是一种使用少量测试材料评估拉伸性能的有前途的技术，但其适用性受到使用现有两种方法确定的屈服力 (F) 估计拉伸屈服强度 (YS) 时存在较大误差的限制。正切、偏移或双线性函数拟合方法。在这项研究中，通过有限元分析确定了基于整个样本厚度发生屈服的屈服力 (F)，并制定了一种方法，用于在声发射 (AE) 技术的支持下根据实验数据确定 F。各种结构钢、铬镍铁合金和铝的 YS-F 相关性表现出出色的线性度和 ±7% 以内的标准误差。基于 SP 变形中塑性不稳定性在力-挠度曲线的拐点 (F, u) 处开始，样品挠度 u 与均匀拉伸应变的相关性优于参数 u（峰值载荷时的挠度）。使用本文中制定的方法和 SP 拉伸相关性通过 SP 测试评估中子辐照 SS 316 的拉伸性能，发现其与单轴拉伸测试结果的偏差在 6-8% 范围内。