混凝土拉压强度尺寸效应的细观非均质机理
Meso-heterogeneity mechanism of the concrete size effect of tension and compression strength
杜敏 1杜修力 2金浏 2卢爱贞2
作者信息
- 1. 北京工业大学 城市与工程安全减灾教育部重点实验室 北京 100124; 防灾科技学院 河北 三河 065201
- 2. 北京工业大学 城市与工程安全减灾教育部重点实验室 北京 100124
- 折叠
摘要
为了从材料细观非均质角度揭示混凝土强度尺寸效应机理，建立了混凝土细观单元等效非均质力学模型，开展了立方体抗拉、抗压强度尺寸效应细观数值模拟研究。研究结果表明：混凝土强度尺寸效应根源于材料细观非均质性，随着模型尺寸的增加，混凝土材料细观单元弹性模量变异系数增大，材料细观非均质性增强，大尺寸模型内部存在更多的低强度单元或缺陷，导致混凝土立方体抗拉、抗压强度降低，极限应变减小，脆性增大；混凝土损伤破坏由少量集中区域，发散扩展形成多条非贯通的裂纹带；数值模拟结果与尺寸效应实验数据相吻合。
Abstract
In order to reveal the size effect meso-heterogeneity mechanism of concrete strength,the meso-element equivalent heterogeneity model was established.Tension and compression tests were simulated for different size meso-heterogeneity models.The results showed that the size effect of concrete is rooted in the meso-heterogeneity mechanism of materials.With the increase of model size,the variation coefficient of meso-element elastic modulus increases and meso-heterogeneity of concrete heightened.Also,more low-strength units or defects were discovered in the large-size model.As a result,the tension and compression strength of concrete and the ultimate strain decreased and the brittleness of concrete strengthened. Concrete damage region extended from the concentrated area to multiple non-penetrating crack zones.
关键词
混凝土/细观非均质/细观单元等效化模型/强度尺寸效应/破坏模式Key words
concrete/meso-heterogeneity/meso-element equivalent model/strength size effect/failure mode引用本文复制引用
基金项目
国家自然科学基金(51408127)
中国地震局教师科研基金(20120104)
出版年
2015
NETL
NSTL
维普
万方数据