全珊瑚海水混凝土冲击压缩性能试验研究与数值模拟

Experimental Study and Simulation of Impact Compression of Coral Aggregate Seawater Concrete

采用直径为75 mm的霍普金森压杆对强度等级为C30和C50的全珊瑚海水混凝土(CASC)以及剑麻纤维增强全珊瑚海水混凝土(SFCASC)进行了冲击压缩试验,并使用LS-DYNA软件对CASC的冲击性能进行了模拟.结果表明:CASC与SFCASC的动态增强因子DIF与应变率ε·s、立方体抗压强度f cu有关,建立了DIF关于ε·s与f cu的二元函数模型;通过试件的破坏形态分析可知剑麻纤维能够有效增强CASC的抗冲击性能,当应变率为52.4 s^(-1)时,CASC-C50试件破坏较为严重,而SFCASC-C50试件在应变率为56.9 s^(-1)时仍能保持完整的形态,只在边缘处出现少量裂缝;采用LS-DYNA软件对CASC-50的冲击压缩过程进行数值模拟,通过试验数据确定了HJC模型参数,模拟的动态抗压强度与试验值的误差在1.0%~4.9%,模拟动态临界应变与试验值的误差在4.3%~18.3%.

Coral aggregate seawater concrete(CASC)with strength grade of C30 and C50 and sisal fiber reinforced coral aggregate seawater concrete(SFCASC)were tested using Hopkinson pressure bar of 75mm diameter.The finite element software LS-DYNA was used to simulate the mechanical response of CASC under impact loading.The results show that the dynamic increase factor(DIF)of CASC and SFCASC is related to strain rate(ε·s)and cubic compressive strength(f cu),and the binary function model of DIF withε·s and f cu is established.According to the failure morphology analysis of the specimens,sisal fiber can effectively enhance the impact resistance of CASC.When the strain rate is 52.4 s^(-1),the CASC-C50 specimens are more severely damaged,while the SFCASC-C50 specimens can maintain complete shape at strain rate of 56.9 s^(-1),with only a few cracks appearing at the edges.The impact process is simulated by LS-DYNA software,and the parameters of HJC model are determined by experimental data.The error between the simulated dynamic compressive strength and the test value is 1.0%4.9%,and the error of the dynamic critical strain is 4.3%18.3%.