【摘要】 通过类岩石材料石膏试件单轴压缩试验,获得材料在荷载作用下从损伤到破坏的整个时间序列的数字图像。以试件表面数字图像的灰度相关性的变化为依据,建立损伤量度来表征材料表面损伤和破坏的发展。通过图像处理,建立损伤演化的二值图,并采用分形和多重分形谱理论对材料表面损伤的演化进行描述。研究结果表明,图像灰度相关性系数分布的演化与试件表面的变形局部化在空间和时间上都存在对应关系。随着试件表面损伤量增加,分形维数与应变之间有很好的线性关系,多重分形谱图的曲线形状从开始的对称光滑单峰形式,逐渐向左侧集中发展,其谱宽逐渐减小。更多还原

【Abstract】 Based on uniaxial compression tests on gypsum specimens,a series of digital images of materials are obtained during the process from damage to failure.According to the gray correlation coefficient of the digital image,the damage magnitude is built to reflect damage evolution of the material.A series of binary images of the damage evolution are obtained by image processing.The fractal and multifractal spectrum theories are adopted to describe the damage evolution on material surface.The results show that the spatial and temporal corresponding relations exist between the distribution evolution of gray correlation coefficient and the localization of surface deformation.With the increase of damage on specimen surface,the relationship between fractal dimension and strain is linear;the curve of multifractal spectrum changes from symmetric single-peak form to left concentrated form and the spectral width decreases.更多还原