摘要
为研究碳纤维高强混凝土工程在多次冲击荷载作用下的安全性,采用直径为74 mm的分离式霍普金森压杆装置及非金属超声波检测装置对不同碳纤维掺量(0%、0.15%、0.3%、0.45%、0.6%)试件在不同冲击次数(1、2、3、4)下纵波波速、损伤因子、峰值应力及能量耗散规律进行研究,并结合电镜扫描(SEM)观察不同冲击次数下试件内部微观结构,分析试件力学性能与碳纤维掺量及冲击次数间的关系。结果表明:碳纤维的掺入能增加试件整体性,减少试件内部裂隙,增大纵波波速,第1次冲击作用会对试件内部裂隙进行“压实”,试件波速随之增大,随着冲击次数的进一步增加,试件损伤度增大,波速降低;碳纤维的掺入能有效增加试件峰值应力,掺量在0.45%时效果最佳,冲击荷载会对试件造成压实和损伤,试件峰值应力先小幅度上升后大幅度下降;冲击荷载作用下试件能量时程变化主要分为三个阶段,纤维掺量在0.3%时试件能量耗散率最高,多次冲击作用会对试件造成损伤累加,其耗能密度显著降低;SEM试验结果表明碳纤维的存在能够有效减少冲击荷载作用下试件内部裂纹扩展度及裂纹数目,试件微观结构与宏观力学性能变化表现出一致性。
In order to study the safety of carbon fiber reinforced high strength concrete under multiple impact loads. The longitudinal wave velocity, damage factor, peak stress and energy dissipation of specimens with different carbon fiber contents(0%, 0.15%, 0.3%, 0.45% and 0.6%) under different impact times(1, 2, 3 and 4) were studied by using a separated Hopkinson pressure bar device with a diameter of 74 mm and a non-metallic ultrasonic testing device. Combined with scanning electron microscope scanning(SEM), the internal microstructure of the specimen under different impact times was observed, and the relationship between the mechanical properties of the specimen and the content of carbon fiber and impact times was analyzed. The results show that the addition of carbon fiber can increase the integrity of the specimen, reduce the internal cracks and increase the longitudinal wave velocity. The first impact will "compact" the internal cracks of the specimen, and the wave velocity of the specimen will increase. With the increase of impact times, the damage degree of the specimen increases and the wave velocity decreases. The addition of carbon fiber can effectively increase the peak stress of the specimen, and the effect is the best when the content is 0.45%. The impact load will cause compaction and damage to the specimen, and the peak stress of the specimen first increases slightly and then decreases greatly. The energy time history change of the specimen under impact load is mainly divided into three stages. The energy dissipation rate of the specimen is the highest when the fiber content is 0.3%. Multiple impact will cause damage accumulation to the specimen, and its energy consumption density will be significantly reduced. SEM test results show that the existence of carbon fiber can effectively reduce the internal crack propagation and the number of cracks under impact load, and the changes of microstructure and macro mechanical properties are consistent.
作者
马学思
许丽
张强
MA Xue-si;XU Li;ZHANG Qiang(Inner Mongolia Transportation Vocational and Technical College,Chifeng 024005,China;Yuncheng Vocational and Technical University,Yuncheng 044000,China;School of Civil Engineering,Taiyuan University of Technology,Taiyuan 030024,China)
出处
《复合材料科学与工程》
CAS
北大核心
2022年第12期24-30,共7页
Composites Science and Engineering
基金
国家自然科学基金项目(51808375)。
关键词
冲击荷载
碳纤维掺量
冲击次数
纵波波速
损伤因子
能量耗散
扫描电镜
impact load
carbon fiber content
impact times
longitudinal wave velocity
damage factor
energy dissipation
scanning electron microscope
