高温后玄武岩纤维混凝土冲击破碎分形特征

任韦波;许金余;刘远飞;苏灏扬

振动与冲击 ›› 2014, Vol. 33 ›› Issue (10) : 167-171.

PDF(1478 KB)
PDF(1478 KB)
振动与冲击 ›› 2014, Vol. 33 ›› Issue (10) : 167-171.
论文

高温后玄武岩纤维混凝土冲击破碎分形特征

  • 任韦波1,许金余1,2,刘远飞1,苏灏扬1
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Fractal characteristics of fragments of basalt fiber reinforced concrete after elevated temperatures under impact loading

  • REN Wei-bo1,XU Jin-yu1,2,LIU Yuan-fei1,SU Hao-yang1

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摘要

采用100 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。

Abstract

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, were investigated by using a 100 mm diameter split Hopkinson pressure bar (SHPB) apparatus. The experimental results reveal that the fragments distribution of specimen statistically has fractal property under impact loading. The higher the temperature and projectile velocity, the severer the fragmentation and the larger the fractal dimension. Compared with PC, the fractal dimension of BFRC decreases at room temperature, 600 ℃ and 800 ℃, and decreases first and then increases with the increase of projectile velocity at 200 ℃ and 400 ℃. The addition of 0.2% (volume fraction) basalt fiber results in relatively higher fractal dimension. The energy dissipation density increases with the increase of fractal dimension under the same temperature, the fractal dimension corresponding to the same energy dissipation density increases with an increase in temperature. There are two critical points in the relationships between fractal dimension and projectile velocity, i.e., initiation projectile velocity and crushing projectile velocity. In this velocity range, the fractal evolution characteristics of fragmentation are obvious, the fractal dimension increases markedly. When the temperature increases, the critical projectile velocity decreases gradually.

关键词

玄武岩纤维混凝土 / 高温 / SHPB / 冲击破碎 / 分形维数

Key words

basalt fiber reinforced concrete / elevated temperature / SHPB / impact crushing / fractal dimension

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任韦波;许金余;刘远飞;苏灏扬. 高温后玄武岩纤维混凝土冲击破碎分形特征[J]. 振动与冲击, 2014, 33(10): 167-171
REN Wei-bo;XU Jin-yu;LIU Yuan-fei;SU Hao-yang. Fractal characteristics of fragments of basalt fiber reinforced concrete after elevated temperatures under impact loading[J]. Journal of Vibration and Shock, 2014, 33(10): 167-171

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