Digital image correlation based high-speed crack tip locatingmethod and its application  

作　　者：曹彦彦 马沁巍 郭文婧 

机构地区：[1]School of Aerospace Engineering,Beijing Institute of Technology,Beijing 100081,China [2]State Key Laboratory of Earthquake Dynamics,Institute of Geology,Earthquake Administration,Beijing 100029,China [3]Beijing Institute of Strength and Environment Engineering,Beijing 100076,China)

出　　处：《Journal of Beijing Institute of Technology》2016年第1期7-16,共10页北京理工大学学报（英文版）

基　　金：Supported by the National Natural Science Foundation of China(11172039,11402023);the Fundamental Research Funding of BIT(20120142021);the State Key Laboratory of Earthquake Dynamics(LED2011B03)

摘　　要：Based on a digital image correlation（DIC）method with the measurements of a high speed crack＇s displacement and strain fields,a technique to accurately and automatically locate its crack tip has been developed.The crack tip is identified by finding the abrupt jump on the opening（or dislocation）curve of a point on the trace of the crack propagation,while the opening is measured through a virtual extensometer technique and the abrupt jump is identified by finding the peak on the curve.The method was verified using a specially designed experiment and applied to measure the critical crack tip opening angle of a rock sample.Because the involvement of analytical models has been avoided and then the good performance could be ensured for low resolution speckle images,this technique is expected to be very useful in the quantitative study of high speed cracks in experiments using high speed cameras.Based on a digital image correlation（DIC）method with the measurements of a high speed crack＇s displacement and strain fields,a technique to accurately and automatically locate its crack tip has been developed.The crack tip is identified by finding the abrupt jump on the opening（or dislocation）curve of a point on the trace of the crack propagation,while the opening is measured through a virtual extensometer technique and the abrupt jump is identified by finding the peak on the curve.The method was verified using a specially designed experiment and applied to measure the critical crack tip opening angle of a rock sample.Because the involvement of analytical models has been avoided and then the good performance could be ensured for low resolution speckle images,this technique is expected to be very useful in the quantitative study of high speed cracks in experiments using high speed cameras.

关 键 词：digital image correlation（DIC） high speed crack crack tip virtual extensometer crack tip opening angle 

分 类 号：O346.1[理学—固体力学]