Strain field investigation of limestone specimen under uniaxial compression loads using particle image velocimetry

作     者：徐金明 程昌宏 陆海平 

作者机构：Department of Civil EngineeringShanghai University Hunan Zhongda Design Institute Company Limited Central South University 

出 版 物：《Journal of Central South University》 (中南大学学报（英文版）)

年 卷 期：2011年第18卷第5期

页      面：1619-1625页

核心收录：

学科分类：08[工学] 081304[工学-建筑技术科学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0802[工学-机械工程] 0813[工学-建筑学] 0801[工学-力学（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：Project(40972191) supported by the National Natural Science Foundation of China Project(09YZ39) supported by the Creative Issue of Shanghai Education Committee,China 

主　　题：rock materials limestone video image strain field uniaxial compression particle image velocimetry 

摘      要：The particle image velocimetry (PIV) method was used to investigate the full-field displacements and strains of the limestone specimen under external loads from the video images captured during the laboratory *** original colorful video images and experimental data were obtained from the uniaxial compression test of a *** eliminate perspective errors and lens distortion,the camera was placed normal to the rock specimen *** converted into a readable format of frame images,these videos were transformed into the responding grayscale images,and the frame images were then *** full-field displacement field was obtained by using the PIV technique,and interpolated in the sub-pixel *** displacement was measured in the plane of the image and inferred from two consecutive *** local displacement vectors were calculated for small sub-windows of the images by means of *** video images were interrogated in a multi-pass way,starting off with 64×64 images,ending with 16×16 images after 6 iterations,and using 75% overlap of the *** order to remove spurious vectors,the displacements were filtered using four filters:signal-to-noise ratio filter,peak height filter,global filter and local *** cubic interpolation was utilized if the displacements without a number were *** full-field strain was then obtained using the local least square method from the discrete *** strain change with time at different locations was also *** is found that the normal strains are dependant on the locations and the crack *** 1.0 and 5.0 s prior to the specimen failure,normal strains increase rapidly at many locations,while a stable status appears at some *** the specimen is in a failure status,a large rotation occurs and it increases in the inverse *** strain concentration bands do not completely develop into the large cracks,and meso-cracks are n