摘要
利用损伤力学的观点,用弹性模量损伤和能量损伤相结合的方法定义损伤变量,分析了基体强度为40MPa、钢纤维含量为0和2.0%的混凝土在4种应变速率(10-5、10-4、10-3、5×10-3s-1)下的单轴压缩试验数据,比较了普通混凝土和钢纤维混凝土在4种应变速率下的损伤特性,并对混凝土材料的损伤机理进行了分析。试验分析表明:①混凝土材料在加载初始阶段普通混凝土的损伤比钢纤维混凝土的损伤小,混凝土内部为微观裂纹的发育发展;当加载到一定程度时,普通混凝土的损伤则比钢纤维混凝土的损伤大,混凝土内部为宏观裂纹的发展和贯穿;②混凝土在加载的初始阶段,普通混凝土的损伤比钢纤维混凝土的损伤小,但应变速率越大,两种混凝土之间的损伤差异越小;③试验加载速率越高,普通混凝土损伤大于钢纤维混凝土损伤时材料的应变越小,对应的损伤值也相应越小;④普通混凝土加载速率越高,损伤程度会随应变加载速率的提高而增加;⑤钢纤维混凝土在加载初始阶段,混凝土中仅有微观裂纹,不同加载速率下,损伤发展趋势一致;在峰值应变后应变速率越高,裂纹扩展和贯穿的速度越快,损伤程度也越大。
The uniaxial compression test data of concrete that the matrix strength is 40MPa and the steel fiber content are 0 and 2.0% under four kinds of strain rate（10^-5,10^-4,10^-3,5×10^-3 s^-1） are analyzed by view of damage mechanics for the method of combining elastic modulus damage with energy damage,then the damage characteristics is compared and the damage mechanism is analyzed for the two kinds of concrete.The results suggest that ① The damage degree of ordinary concrete is less comparison with the Steel Fiber Reinforced Concrete（SFRC） and the micro-cracks initiation and development in the initially loading stage,then the damage degree of ordinary concrete will be more comparison with SFRC and macro-crack evolution and propagation when loading to some extent;② The damage degree of ordinary concrete is less comparison with the SFRC in the initially loading stage,however the damage degree difference between two kinds of concrete is less when the strain rate is higer;③ The loading rate is higher,the concrete material strain is smaller when the damage degree of ordinary concrete is more comparison with the SFRC,and corresponding to the value of the damage is smaller;④ The loading rate of ordinary concrete is higher and the damage degree is higher;⑤ In the initially loading stage,the SFRC has only the micro-cracks and the damage degree is similar under the different loading rate,the strain rate is higher,the development of cracks is faster and the damage degree of SFRC is more when the strain is bigger than value of peak-strain.
出处
《混凝土》
CAS
CSCD
北大核心
2010年第7期48-50,53,共4页
Concrete
基金
国家自然科学基金(50679039)
国家自然科学基金重大项目(90510017)
三峡大学青年科学基金(KJ2009A034)
关键词
混凝土
应变率效应
损伤
concrete
strain rate effect
damage
