【摘要】 目的为了克服常规无损检测方法不能动态监测吊杆损伤程度和类型,提出利用声发射技术监测吊杆损伤的活性.方法使用上升时间和持续时间关系图确定有效信号,设置浮动门槛值和增设警卫传感器去掉环境噪声;运用声发射参数法分析吊杆内水泥砂浆和钢绞线的损伤程度,并且还使用波形分析技术判断吊杆的损伤类型;在此基础上,对四川峨边大渡河拱桥的所有吊杆进行了全面的声发射在线监测.结果结果表明声发射信号幅值、能量、计数随时间实时变化图能直观显示吊杆的损伤程度关系;波形和频率范围上的差异能有效判断各种损伤类型,其监测结果与实际情况非常吻合.结论采用合理的降噪手段和识别方法,能够从强噪声环境中提取有效声发射信号,声发射特征参数相关图和波形分析技术能够动态监测拱桥吊杆的损伤程度和类型.更多还原

【Abstract】 Conventional non-destructive methods can’t be dynamically monitored the suspenders’damage levels and types,so acoustic emission(AE) technique is proposed to monitor its activity.The validity signals are determined by the relationship with AE rise time and duration time.The ambient noise is eliminated using float threshold value and placing a guard sensor.The cement mortar and steel strand damage level is analyzed by AE parameter method and damage types are judged by waveform analyzing technique.Based on these methods,all the suspenders of Sichuan Ebian Dadu river arch bridge have been monitored using AE techniques.The monitoring results show that AE signal amplitude,energy and counts can visually display the suspenders’damage levels,the difference of waveform and frequency range express different damage type.The testing results are well coincide with the practical situation.更多还原