复杂结构体系中声发射传播与能量衰减特性试验研究

Experimental study on acoustic emission signal propagation property and energy attenuation characteristics in complicated structural system

为研究声发射信号在水电站厂房等复杂组合结构中的传播性能,在复杂梁柱结构中各代表位置布置了多组声发射探头并采集拟声发射信号,研究了声发射信号在混凝土结构、圆形空心钢管柱,圆形钢管混凝土柱中的传播性能,并对比了功率谱图及声发射参数。结果表明:(1)声发射信号传播经过柱体时有明显的能量衰减,且经过圆形钢管混凝土柱的能量衰减程度大于圆形空心钢管柱;(2)声发射信号从混凝土结构传至圆形钢管混凝土柱时,能量衰减率大于混凝土结构中的传播,能量衰减主要集中在10~50 kHz频率段;(3)声发射信号从混凝土结构传至圆形空心钢管柱中时,探头所接收表征能量值大于源信号处能量值。柱体影响范围内,传播经过圆形空心钢管柱的声发射信号等效传播速度大于混凝土中传播速度。对于圆形钢管混凝土柱,等效速度小于混凝土中传播速度。研究成果对复杂结构体系声发射检测具有重要参考价值。

In order to study the acoustic emission signal propagation property in complicated structural system such as hydropower house,several sets of acoustic emission probes are arranged at all the representative locations in complicated beam-column structure and the corresponding echoic emission signals are collected,and then the propagation properties of acoustic emission signals in concrete structure,circular hollow steel column and circular concrete-filled steel column are studied,while the power spectrogram and the acoustic emission parameter are compared as well. The result shows that：（ 1） obvious energy attenuation is there during the acoustic emission signal propagation through column,and the degree of the energy attenuation through the circular concrete-filled steel column is larger than that through the circular hollow steel column;（ 2） when acoustic emission signal propagates from concrete structure to circular concrete-filled steel column,the energy attenuation rate is larger than that of the propagation in concrete structure and mainly concentrates in the frequency band of 10 ~ 50 kHz;（ 3） when acoustic emission signal propagates from concrete structure to circular hollow steel column,the characterized energy values received by the probe are larger than those from the source signal. Consequently,the equivalent propagation speed of acoustic emission signal through circular hollow steel column is larger than that through concrete within the column impacting scope. For the circular concrete-filled steel column,the equivalent propagation speed of acoustic emission signal is less than that in concrete. The study result has an important reference value for the acoustic emission detection of complicated structural system.