中文摘要：

针对海洋平台水下钢结构无损检测的需要,研究在空气、淡水和海水作为耦合介质的情况下,声发射波在钢结构传播过程中幅值和能量的变化趋势,以及幅值和能量损失的原因。基于声发射波反射原理,分析声发射波在钢结构中传播的多径效应及波形转换特性,并解释了时域波形发生分离的原因。根据实验结果,分析了盐度对声发射波传播特性的影响。该项研究为提高海洋平台声发射检测中故障源的精确定位提供了实验依据。

英文摘要：

For the needs of nondestructive testing for underwater steel structures of offshore platforms,the trend and the cause for the amplitude and energy loss of acoustic emission wave propagating in steel structures under the conditions of air and fresh water and sea water as the coupling medium are studied respectively.Based on the reflection theory of acoustic emission wave,the multi-path effect and the wave conversion are analyzed and the cause for dispersion of time-domain waveform is explained.Based on experimental results,the effect of salinity for propagation characteristic of acoustic emission wave is analyzed.The contents of this paper offer an experimental basis for improving the location precision of acoustic emission sources in acoustic emission of offshore platforms.