摘要
对数字图像相关(DIC)方法进行相关搜索时,提出将Newton-Raphson(N-R)迭代方法与粒子群优化(PSO)算法相结合并交替使用.PSO算法使粒子在搜索区域内的位置不断地发生改变,这为N-R迭代方法提供了众多的初值,N-R迭代方法在迭代过程中对位移和应变不断地进行修正.研究了粒子的最大飞行速度对粒子搜索轨迹及搜索结果准确性的影响.研究发现,对于大位移点的搜索,搜索区域及粒子的飞行速度应较大.对含孔洞的砂土试样进行了单轴压缩实验.在对一系列散斑图进行相关搜索时,以前面的搜索确定的点的变形后坐标作为后面搜索时搜索区域的中心,在不同变形破坏阶段,计算了孔洞下方一小块区域内点的位移及应变增量,观察到压应力方向上的拉伸应变局部化带.当样本子区尺寸为17像素且测点间距为1—4像素时,局部化带宽度为1.2—1.6mm.
The Newton-Raphson（N-R） iteration method and the particle swarm optimization （PSO） algorithm were combined and used alternatively during correlation searching in a digital image correlation method. Positions of particles change in a searching region according to the PSO algorithm, providing many initial values for the N-R iteration method. During the N-R iteration, values of displacement and strain were updated. The influence of the maximum particle velocity on the particles＇ trajectories and on the accuracy of searching results was studied. Results showed that small searching regions and small particle velocities cannot be suggested for points with large displacements. Uniaxial compressive tests were carded out for sand specimens with circular holes. During correlation searching time, coordinates of points were obtained coordinates were selected as later central for a series of speckle images taken at different according to former displacement results and these points of searching regions. At different deformation and failure stages, the incremental displacement and strain were calculated in a local region near the hole. A localized tensile strain band was observed in the direction of the compressive stress. The width of the band was found to be about 1.2--1.6mm for subset size of 17 × 17 pixels and for spacing of points of 1--4 pixels.
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2013年第5期908-917,共10页
Journal of Basic Science and Engineering
基金
辽宁省煤矿液压技术与装备工程研究中心(辽宁工程技术大学)开放基金(CMHT-201205)
国家重点基础研究发展计划(2010CB226803)
辽宁省高等学校优秀人才支持计划(LJQ2011030)
