Data for: The Development of a Novel Small Ring Specimen Tensile Testing Technique

The wide scale use of small specimens in routine testing programs could significantly reduce material resource requirements (factors of 10 are easily achievable). This is a major benefit to situations where there is not enough material to manufacture conventional, full-size specimens, such as first-stage gas turbine blade roots. However, limitations exist due to concerns over size effects, manufacturing difficulties, uncertainties related to the application of representative loading conditions and complex interpretation procedures of non-standard data. Due to these limitations, small specimen testing techniques have been mostly applied in ranking exercises and to determine approximate or simple material parameters such as Young’s modulus, minimum creep strain rate and fracture toughness. The small ring method is a novel, high sensitivity small specimen technique for creep testing that has been extended in the present work to the determination of tensile material properties. The main advantages of the small ring specimen are that it is self-aligning and has a large equivalent gauge length in comparison to other small specimens, resulting in much higher testing sensitivity. In the present work, this specimen type mimics conventional, full-size, monotonic testing, allowing for observations of elastic and plastic material response to be made. Wrought aluminium alloy 7175-T7153 small rings were tested at room temperature at 5 different loading (displacement) rates and the results compared to conventional, full-size, monotonic specimen equivalents. Finite element analysis was conducted in order to evaluate the equivalent gauge section and equivalent gauge length in the small ring specimen (which varied between circa 0.35-1.4mm2 and 25-45mm, respectively) to facilitate these comparisons. An analytical solution has also been derived in order to validate the finite element analysis.

小试样（small specimens）在常规检测程序中的大规模应用，可显著降低材料资源需求，轻松可实现10倍量级的缩减。这对于材料量不足以制备常规全尺寸试样的场景具有重要价值，例如一级燃气轮机叶片榫头。
然而该方法仍存在诸多局限：诸如尺寸效应带来的性能顾虑、制造加工难度、典型加载条件施加相关的不确定性，以及非标准检测数据的复杂解读流程。受限于这些问题，小试样检测技术目前大多仅应用于排序试验，以及测定近似或简单的材料参数，如杨氏模量（Young’s modulus）、最小蠕变应变率（minimum creep strain rate）与断裂韧性（fracture toughness）。
小圆环法（small ring method）是一种新颖的高灵敏度蠕变检测小试样技术，本研究将其拓展至拉伸材料性能的测定。
小圆环试样的核心优势在于其自对准特性，且相较于其他小试样拥有更大的等效标距长度（equivalent gauge length），因此可获得更高的检测灵敏度。
本研究中，该试样类型可模拟常规全尺寸单调加载试验，能够观测材料的弹性与塑性响应。
我们在室温下以5种不同的加载（位移）速率对变形铝合金7175-T7153小圆环试样进行了检测，并将结果与常规全尺寸单调加载试样的等效结果进行了对比。
为辅助上述对比工作，我们开展了有限元分析（finite element analysis），以评估小圆环试样的等效截面面积（equivalent gauge section，范围约0.35~1.4mm²）与等效标距长度（范围约25~45mm）。
此外，我们还推导了解析解（analytical solution）以验证有限元分析的结果。