铝合金薄板疲劳裂纹的非线性声学特性.pdf

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第46卷第18期
机械工程学报
Vol.46o.18
2010年9月
JOURNAL OF MECHANICAL ENGINEERING
Sep
2010
DOI:10.3901/JME.2010.18.071
铝合金薄板疲劳裂纹的非线性声学特性
高桂丽李大勇董静薇2石德全石旭东3
(1.哈尔滨理工大学材料科学与工程学院哈尔滨150040;
2.哈尔滨理工大学测控技术与通信工程学院哈尔滨150040
3.中国民航大学航空自动化学院天津300300)
摘要:在没有任何损伤的铝合金薄板中,主要表现为原子间的非线性,以至于非线性声学特征不明显并很难测暈;然而当铝
合金薄板中出现疲劳损伤时,将产生明显的非线性声学特征,这对于识别铝合金薄板中的疲劳损伤十分有利。推导超声波在
含有疲劳裂纹的固体金属中传播时非线性声学特征方程。利用非接触激光测振仪、任意波形发生器、数字示波器和计算机等
组建铝合金簿板疲劳裂纹试验系统,并以含有疲劳裂纹的2024铝合金薄板为研究对象,利用该系统,在单频超声波即中心
频率为270kHz2激励下,对超声波在2024铝合金海板中传播的非线性声学特性进行试验研究。结果表明,高次谐波可作为
表征疲劳裂纹或缺陷的特征量。根据不同点的扣描结果,获得时域峰值幅度和频率幅度与打描位置之间的关系,由此可大致
确定疲劳裂纹的位置。
关键词:非线性声学特性疲劳裂纹铝合金薄板
中图分类号:TB31TB52
Nonlinear Acoustic Characteristics of Fatigue
Cracks in Aluminum Alloy Sheet
GAO Guili LI Dayong DONG Jingwei" SHI Dequan SHI Xudong
( 1. Department of Material Science &Engineering, Harbin University Science and Technology, Harbin 150040
2 Department of Measurement-control Technology &Communications Engineering,
Harbin University Science and Technology, Harbin 150040;
3. Aeronautical Automation College, Civil Aviation University of China, Tianjin 300300
Abstract: Intact aluminum alloy sheet mainly presents as interatomic nonlinearity, so the nonlinear acoustic characteristics are
unobvious and difficult to measure. However, when the same aluminum alloy sheet is damaged, its nonlinear acoustic characteristics
are obvious, which is favorable for identifying fatigue crack in aluminum alloy sheet. The equation of nonlinear acoustic
characteristics is derived when ultrasonic wave transmits in solid metal with fatigue cracks. A fatigue crack test system composed of
piezoelectric transducer, non-contact laser vibration meter, arbitrary wave generator, digital oscillograph and computer is constructed
When the sheet is excited by a sin e eque ultrasonic wave(enter frequency 70khz), the nonlinear acoustics characteristics of
ultrasonic wave transmitting in 2024 aluminum alloy sheet with fatigue crack is studied by using this system. The experimental results
show that the high harmonics can be taken as the characteristic parameters to characterize the fatigue cracks or defects. Based on the
scanning results at different points, the relationship between time domain peak magnitude, frequency magnitude and scanning
position is obtained, thereby the positions of fatigue cracks can be approximately determined
Key words: Nonlinearity Acoustic characteristics Fatigue crack Aluminum alloy sheet
国家自然科学基金(60772104)和黑龙江省留学归国人员基金(LCOC01)
资助项月。20090902收到初稿,20100415收到修改稿