轴压与偏压状态下混凝土损伤全过程声发射特征参数分析

Analysis of Acoustic Emission Characteristic Parameters During Whole Damage Process of Concrete under Uniaxial and Eccentric Compressions

声发射技术可以评估混凝土的损伤演化过程。为合理描述混凝土的受压损伤演化过程,开展了轴压和偏压状态下混凝土损伤全过程的声发射试验,分析了轴压和偏压状态下混凝土损伤全过程声发射特征参数的演化规律,进而合理遴选了描述混凝土损伤演化过程的声发射特征参数,揭示了混凝土应力-应变曲线特征点与声发射特征参数特征点之间的对应关系。分析表明:振铃计数、持续时间、幅值、信号强度和平均频率可以较好地表征轴压与偏压状态下混凝土损伤的演化规律;混凝土试件受压破坏过程中声发射特征参数特征点与应力-应变曲线特征点之间具有高度的相关性,其中声发射特征参数特征点中的第一个分界点对应于应力-应变曲线弹性阶段的起点,第二个分界点对应于应力-应变曲线的峰值应力点,信号强度的最大突变点对应于应力-应变曲线的开裂点。

Damage evolution process(DEP)of concrete can be evaluated by acoustic emission(AE)technology.In order to resonably describe the DEP of concrete,AE test of the whole process of concrete damage under uniaxial and eccentric compressions were carried out and the evolution law of AE characteristic parameters(AECPs)in the whole process of concrete damge were analyzed.Moreover,the optimal AECPs were resonable selected,and the relationship between the characteristic points of stress-strain curve and AECPs was revealed.Results show that the AECPs including counts,duration,amplitude,signal strength and average frequency well describe DEP of concrete.Meanwhile,there is a high correlation between characteristic points of AECPs and stress-strain curve during the compression failure of the concrete specimen.The first demarcation point of AECPs corresponds to the starting point of elastic stage of stress-strain curve,the second demarcation point corresponds to the peak stress point of stress-strain curve,and the maximum mutation point of signal strength corresponds to the cracking point of stress-strain curve.