高温后玄武岩纤维混凝土冲击破碎分形特征  

Fractal characteristics of fragments of basalt fiber reinforced concrete after elevated temperatures under impact loading

作　　者：任韦波[1] 许金余[1,2] 刘远飞[1] 苏灏扬[1] 

机构地区：[1]空军工程大学机场建筑工程系,西安710038 [2]西北工业大学力学与土木建筑学院,西安710072

出　　处：《振动与冲击》2014年第10期167-171,188,共6页Journal of Vibration and Shock

基　　金：国家自然科学基金资助项目(51078350);国家自然科学基金资助项目(51208507);陕西省自然科学基金资助项目(2011JM6014)

摘　　要：采用Ф100 mm分离式霍普金森压杆试验系统,对高温后素混凝土（Plain Concrete,PC）及玄武岩纤维混凝土（Basalt Fiber Reinforced Concrete,BFRC）在冲击荷载作用下破碎块度分布、破碎分维及能耗特性进行研究。结果表明,冲击破坏后试件破碎块度分布为统计意义的分形,温度及弹速的升高导致试件破碎程度及分维值总体增大;BFRC分维在常温及600℃~800℃时普遍小于PC,在200℃~400℃时随弹速提高较PC先减小后增大,纤维掺量为0.2%时BFRC分维相对较大;同一温度下试件能耗密度随分维的增大而增大,相同能耗密度下分维随温度的升高而增大;BFRC分维随弹速的变化有两个临界速度特征点：起裂临界及粉碎临界弹速,在此弹速范围内,试件破碎分形演化特征明显,分维随弹速提高显著增大,且临界弹速随温度的升高逐渐下降。The dynamic fragmental characteristics of plain concrete （PC）and basalt fiber reinforced concrete （BFRC）after different temperatures including fragments distribution,fractal dimension and energy dissipation capacities under impact loading were investigated by using a 100 mm diameter split Hopkinson pressure bar （SHPB）apparatus.The experimental results revealed that the fragment distribution of specimens statistically has a fractal property under impact loading.The higher the temperature and projectile velocity,the severer the fragmentation and the larger the fractal dimension;the fractal dimension of BFRC is smaller than that of PC at room temperature and the range of 600 ℃to 800℃;compared with the fractal dimension of PC,that of BFRC decreases firstly and then increases with increase in projectile velocity at the range of 200 ℃ to 400 ℃;the volume fraction of 0.2% basalt fiber leads to a relatively higher fractal dimension of BFRC;the energy dissipation density increases with increase in fractal dimension under the same temperature,the fractal dimension under the same energy dissipation density increases with increase in temperature;there are two critical velocity points in the relationship between the fractal dimension of BFRC and projectile velocity,i.e., initial fracture critical projectile velocity and crushing critical projectile velocity;in this velocity range,the fractal evolution characteristics of fragmentation are obvious,the fractal dimension increases with increase in projectile velocity markedly;when the temperature increases,the critical projectile velocity drops gradually.

关 键 词：玄武岩纤维混凝土 高温 SHPB 冲击破碎 分形维数 

分 类 号：O347[理学—固体力学] TU528.01[理学—力学]