| 龚裕煌,孙晨,陈巨兵*.微小缺陷对缺口前端疲劳应变场影响的实验研究[J].实验力学,2020,35(5):729~737 |
| 微小缺陷对缺口前端疲劳应变场影响的实验研究 |
| Experimental study on the influence of micro defects on the fatigue strain field near the notch |
| 投稿时间：2019-10-27 修订日期：2019-12-25 |
| DOI：10.7520/1001-4888-19-197 |
| 中文关键词: 数字图像相关 微小缺陷 疲劳应变场 缺口 单调塑性区 |
| 英文关键词:digital image correlation micro defect fatigue strain field notch monotonic plastic zone |
| 基金项目:国家自然科学基金(11902196, 11732009)资助 |
|
| 摘要点击次数: 616 |
| 全文下载次数: 4208 |
| 中文摘要: |
| 基于二维数字图像相关方法与原位观测技术，研究了含缺陷构件缺口前端的疲劳变形场特性。以7075-T6铝合金为母材，分析了3种不同缺陷位置对于缺口前端疲劳应变累积、有效应变大小以及单调塑性区演变的影响。实验中采用显微镜在100倍的放大倍率下采集散斑图像，基于分割辅助数字图像相关方法测量缺口前端疲劳应变场。实验结果表明，微小缺陷的位置对于缺口前端应变大小以及分布的影响有着明显的不同。位于缺口前方中轴线偏左45°的微孔导致有效应变有着明显的增加，同时也加剧了单调塑性区的扩展；位于缺口中轴线上的微孔和位于缺口中轴线左侧垂直线上的微孔在一定程度上抑制单调塑性区的形状大小，对于塑性区的扩展影响较小。应变分量分布的对比结果表明，微孔对缺口前端应变场的影响与微孔对水平与竖直方向正应变的改变有关。 |
| 英文摘要: |
| Based on the two-dimensional digital image correlation method and in-situ measurement technique, the fatigue strain fields near the notch of the specimens that contain small defects are studied. The 7075-T6 aluminum alloy is chosen as the base material and the effects of three different defect locations on fatigue strain accumulation, equivalent strain and evolution of monotonic plastic zone at notch front are quantitatively analyzed. The speckle images are captured by a microscope at 100 times magnification, and the deformation fields near the notch are measured based on the segmentation-assisted digital image correlation method. The results show that the location of the micro-defects has a significantly different effect on the strain values and distributions of the notch vicinities. The equivalent strain is obviously increased and the expansion of the monotonic plastic zone is exacerbated when the defect is located in the front of the notch with angle of 45° from the central axis to the left. The micro holes on the axis in the middle of the notch and on the vertical line to the left of the mid-axis in the notch inhibit the shape and size of monotonic plastic zone to some extent, but have little influences on the expansion of the plastic zone. The comparison of strain component distribution shows that the above phenomena are mainly caused by the increase of the vertical normal strain in the situation that the specimen has a front-left defect. |
| 查看全文 下载PDF阅读器 |
| 关闭 |
