【摘 要】
：
本文的主要目的是通过非线性Lamb波对板状材料在疲劳损伤中出现的微裂纹进行表征.近几年的研究表明非线性超声技术比传统线性超声技术对损伤更敏感,能够表征材料细微的性能退
【机 构】
：
华东理工大学机械与动力工程学院承压系统与安全教育部重点实验室,上海200237重庆后勤工程学院,重庆401331江苏省特种设备安全监督检验研究院,江苏南京210036
【出 处】
：
2017年西安-上海声学学会第五届声学学术会议
论文部分内容阅读
本文的主要目的是通过非线性Lamb波对板状材料在疲劳损伤中出现的微裂纹进行表征.近几年的研究表明非线性超声技术比传统线性超声技术对损伤更敏感,能够表征材料细微的性能退化.微裂纹萌生之后在一定阈值内以很慢的速率扩展,一旦超过这个阈值,微裂纹迅速扩展,在很短的时间内发生断裂,可能造成严重的安全事故.因此必须在早期对微裂纹进行检测,对于有效保证工程构件的安全运行具有要的理论价值和现实意义.已有的研究所涉及微裂纹尺寸大都是肉眼可见且超过lmm的.本文使用非线性Lamb波方法,对长度在0.5mm内的微裂纹进行了超声非线性测量,对比Lamb波基频幅值和非线性参量变化情况,非线性参量在材料寿命周期内呈现先上升后下降的趋势,而基频幅值基本保持不变,表明Lamb波非线性可望能为早期表征微裂纹的准确评价提供一条有效途径.
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