摘要
针对以缺陷密度为参量的细观损伤演化模型的局限性 ,着重研究了微裂纹尺寸对损伤演化的影响。提出了含三相正交分布等尺寸微裂纹的准脆性材料稳定扩展的细观损伤演化模型。给出了微裂纹特征尺寸随应力变化的显式表达式 ,并由此得到了含微裂纹的准脆性材料损伤本构关系。通过实例 ,对初始含有相同密度、不同尺寸和数量的微裂纹的两种混凝土材料在单向拉伸载荷下的损伤演化进行了数值计算和比较。结果证实 :含大尺寸微裂纹的材料损伤发展较快 ,相应地 ,加载到同一应力水平时 。
The effect of the microcracks size on damage evolution was investigated to overcome the limitations of damage models based only on defect density. A micro mechanical damage evolution model with the crack size effect was proposed for quasi brittle materials. The stable growth of cracks in a brittle material with three mutually perpendicular families of microcracks under proportional tensile loads was studied. An explicit expression was derived for the variation of crack size with stress. A micro mechanical damage constitutive equation was then given. As an example, the damage evolutions in two kinds of concrete, initially having the same crack density but different crack sizes and quantities, were compared numerically. The results verify that the material damage with large microcracks develops more rapidly than that with small microcracks. Accordingly, for the same stress level, the strain of the material with large cracks is greater than that with small cracks.
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2000年第5期88-91,共4页
Journal of Tsinghua University(Science and Technology)
基金
中国科学院"九五"基础性研究重大项目!(KJ951-1-201)
关键词
准脆性材料
细观损伤演化
尺寸效应
微裂纹扩展
quasi brittle material
micro mechanical damage evolution
microcrack size effect
stable growth of microcrack
