基于二维DIC的脆性材料拉伸应力-应变曲线测定
Determination of tensile stress-strain curve of brittle materials based on two-dimensional digital image correlation
Received:February 16, 2017  Revised:March 31, 2017
DOI:10.7520/1001-4888-17-023
中文关键词:  数字图像相关  应力-应变曲线  脆性材料  光学引伸计  双反射镜成像  应变误差
英文关键词:digital image correlation  stress-strain curve  brittle material  optical extensometer  dual-reflector imaging  strain error
基金项目:国家自然科学基金(11402074, 51679078)资助
Author NameAffiliation
ZHU Fei-peng* College of Mechanics and Materials, Hohai University, Nanjing 211100, China 
GONG Yan College of Mechanics and Materials, Hohai University, Nanjing 211100, China 
BAI Peng-xiang College of Mechanics and Materials, Hohai University, Nanjing 211100, China 
LEI Dong College of Mechanics and Materials, Hohai University, Nanjing 211100, China 
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中文摘要:
      在应变测量中,基于普通二维数字图像相关(2D-DIC)的光学引伸计易受到离面刚体位移的影响,从而使得应变测量精度不高。为此,提出了基于双反射镜成像技术的光学引伸计,将试样正反面同时记录在单相机的成像靶面上。在试样正反面对应位置各置一个光学引伸计,取两者应变平均值,则可消除离面刚体位移对光学引伸计应变测量结果的影响。基于该引伸计,开展了环氧树脂和铸铁两类脆性材料的单轴拉伸实验,分别得到了应力-应变曲线。实验结果表明,本文提出的引伸计比基于普通二维DIC的光学引伸计具有更高的应变测量精度,是一种便捷、高效、高精度的应变测量方法,非常适用于脆性试样的应变测量。
英文摘要:
      In strain measurement, the optical extensometer based on ordinary two-dimensional digital image correlation (2D DIC) is easily affected by out-of-plane displacement of rigid body, therefore, the accuracy of strain measurement is not high. For this purpose, an optical extensometer based on dual-reflector imaging technique is proposed, which may simultaneously record specimen's both positive and negative sides on the imaging target surface of single camera. Each optical extensometer is placed at corresponding position on both positive and negative surface of sample. Taking the average value of two strains, the effect of rigid body out-of-plane displacement on strain measurement of optical extensometer may be eliminated. Based on the proposed extensometer, uniaxial tensile experiment of two kinds of brittle material including epoxy resin and cast iron, were carried out, and stress-strain curves were obtained, respectively. Experimental results indicate that the proposed extensometer can provide higher strain measurement accuracy than that from ordinary 2D DIC extensometer, and is a convenient, high-efficiency and high-accuracy strain measurement method, suitable for strain measurement of brittle materials.
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