Optimization of clamped beam geometry for fracture toughness testing of micron-scale samples
Optimization of clamped beam geometry for fracture toughness testing of micron-scale samples
复制标题
用于微米级样品断裂韧性测试的夹紧梁几何形状优化
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
V. Jayaram
中科院分区：
文献类型：
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作者：
B. Nagamani Jaya;S. Bhowmick;S. Asif;O. L. Warren;V. Jayaram
由于结构系统的持续小型化，小规模的断裂韧性测量多年来得到了突出的重视。由于微观结构的复杂性或尺寸和几何效应，对散装材料进行的测量不能外推到较小的长度尺度。根据材料性能和使用中使用的设备的类型，已经提出了许多新的几何形状用于在小长度尺度上测量断裂性能。现场测试提供了必要的环境来观察这些长度尺度上的裂缝，从而确定这些系统中的实际失效机制。在本文中，对先前提出的弯曲双固支梁的几何形状进行了几点改进，以测量断裂韧性。在单调和循环加载条件下，研究了梁的R曲线和疲劳效应。除了基于扫描电子显微镜的原位测试在这类测试中提供的优势外，有限元还被用作模拟工具来取代繁琐和昂贵的实验来优化几何形状。本文描述了对固定梁弯曲这一特殊几何形状所做的所有改进，以进行各种断裂性能测量。
Fracture toughness measurements at the small scale have gained prominence over the years due to the continuing miniaturization of structural systems. Measurements carried out on bulk materials cannot be extrapolated to smaller length scales either due to the complexity of the microstructure or due to the size and geometric effect. Many new geometries have been proposed for fracture property measurements at small-length scales depending on the material behaviour and the type of device used in service. In situ testing provides the necessary environment to observe fracture at these length scales so as to determine the actual failure mechanism in these systems. In this paper, several improvements are incorporated to a previously proposed geometry of bending a doubly clamped beam for fracture toughness measurements. Both monotonic and cyclic loading conditions have been imposed on the beam to study R-curve and fatigue effects. In addition to the advantages that in situ SEM-based testing offers in such tests, FEM has been used as a simulation tool to replace cumbersome and expensive experiments to optimize the geometry. A description of all the improvements made to this specific geometry of clamped beam bending to make a variety of fracture property measurements is given in this paper.