摘要
基于陶瓷内部缺陷分布的随机性,建立Mises破坏准则液压和轴压共同作用下陶瓷材料的损伤本构模型.利用泰勒级数将本构方程中的exp[-((ε1)/(ε*))~m]项展开,由于陶瓷的应变仅为10^(-3)量级,只取展开后的前四项,将本构方程简化.利用Al_2O_3陶瓷的准静态轴向压缩试验确定模型里面的参数,并得出与峰值应力对应的累积损伤度(即临界损伤度D_c).结果表明:模型参数少且易于确定;模型能反映围压效应,即可以体现陶瓷材料强度随液压变化的规律,可以通过不同围压下陶瓷应力—应变全曲线特征及在不同围压下峰值应力与应变确定模型参数;模型参数确定方法揭示了模型参数的物理意义;临界损伤度D_c与峰值应力一一对应,因此,D_c可以作为与强度参数类似的量表征破坏与否.
Based on random distribution of interior defects in ceramics, a statistical damage constitutive model for ceramics was developed by using the Mises failure criterion and the statistical theory under hydraulic pressure and external force, exp[-（ε＊^-ε1）^m] in Taylor series was expanded and because the staring capacity of ceramics was of 10^-3 order, only the first four items were taken and the constitutive model was thus simplified. The parameters were determined by quasi-static axial compression of ceramics, and the damage cumulation （critical damage） corresponding to the peak stress was obtained. The results show that the parameters are easy to be determined. The model can reflect the confining pressure effect, and the law of the ceramics strength changing with the hydraulic pressure can be shown. The statistical parameters in the constitutive model were solved by using the characteristics of the full stress-strain curve of ceramics under the specific hydraulic pressure and the relationship between the characteristic parameters （the stress and strain at the peak-stress point）. The way of determining the parameters indicates the physical meaning of the parameters of the model. The critical damage Dc is one-to-one correspondence to the peak stress, so the Dc is similar to intensive parameters, by which it can be judged that the ceramic is a failure or not.
出处
《兰州大学学报（自然科学版）》
CAS
CSCD
北大核心
2010年第2期117-120,共4页
Journal of Lanzhou University(Natural Sciences)
基金
国家自然科学基金创新群体基金项目(50621403)
国家重点基础研究发展计划(973计划)项目(2009CB724606)
