摘要
搭建了一套金属厚度测量系统,其中激光器用于激励产生超声波,激光干涉仪和压电换能器分别用于接收激励产生的超声纵波信号。根据激光超声产生的机理,建立了纵波声束指向性模型,确定了影响声束指向性的因素,并分别给出了激光垂直入射下干涉仪和压电换能器接收超声波幅值的公式;实验研究了离焦量对测厚信号的影响,发现等量激光脉冲激励下,随着离焦量的增加会出现先增大后减小最后消失的现象,与理论计算结果相吻合,证实了该研究结果的有效性。
A metal thickness measurement system was presented, in which laser was used for exciting the ultrasounds, while interferometer and piezoelectric transducer（PZT） were adopted for receiving longitudinal acoustic waves. In accordance with mechanism of laser ultrasonic generation, the directivity model for longitudinal acoustic beam and the influencing factors were established and determined respectively, and formulas of two receiving modes were given as well. The effect of defocusing amount on thickness measurement was investigated, discovering phenomena that it would first increase then decrease finally disappear varying with increase of defocusing amount under the same laser pulse energy, consistent with the theoretical results, confirming the effectiveness of the study results.
出处
《红外与激光工程》
EI
CSCD
北大核心
2017年第B12期7-12,共6页
Infrared and Laser Engineering
基金
山东省自然科学基金(ZR2016FB26)
山东省重点研发计划(科技攻关部分)(2016GGX101026)
山东省重点研发计划项目(创新型产业集群专项计划)(2016ZDJQ0401)
山东省重点研发计划(公益类专项)(2017GGX201005)
关键词
离焦量
激光超声
测厚
激光干涉仪
压电换能器
defocusing amount
laser ultrasound
thickness measurement
laser interferometer
piezoelectric transducer
