砂浆板冲击荷载下声发射定位试验研究

Test Study on Acoustic Emission Location of Cement Mortar Plate by Shock Load

在混凝土静载声发射研究基础上,提出基于声发射定位的混凝土冲击荷载研究方法,通过锤击、均匀冲击荷载试验,采用逐级递增循环冲击加载方式研究砂浆板的破裂失稳过程,及其内部裂纹萌生、扩展形成裂缝至最终贯穿的演化模式。结果表明,声发射事件产生主要由裂缝扩展引起,并随冲击力变化表现不同特征:在初始冲击荷载至初始裂缝出现之前,声发射活动不明显;随动载增大试件出现裂纹,声发射事件明显增多;裂纹稳定扩展成裂缝至贯穿前声发射活动异常活跃,声发射事件变化率最大;裂缝一旦贯穿继续冲击不再出现声发射活动。裂缝贯穿瞬间虽不产生声发射事件,但仍可根据声发射定位图走势推断。

On the basis of concrete static acoustic emission research,proposed the research method of the concrete impact loads based on acoustic emission location,through the shock loading test of hammering and uniform,Incremental cycle shock loading to study rupture instability process of cement mortar plate,and,internal crack initiation and propagation of cracks to form the final penetrate evolution model are used.The results show that the AE events generated mainly due to the propagation of crack which caused by shock force,and changes with the different characteristics： AE activity is not obvious,before the initial shock load to the initial crack; with the dynamic load increase specimen crack,AE event increased obviously; crack stable propagation fracture through AE prior to the activity of the very active,AE events rate maximum; There is no AE activity once through the cracks continue to shock.Nonetheless,still conclude it based on the map trend of AE location.