使用弯曲共振法测量复合试件阻尼参数时，发现频响曲线有时会在共振频率附近产生“劈叉”现象，表现出两个峰值，与一般经验不符。建立了悬臂梁试件受到不同方向激励的耦合振动模型，通过信号合成复原了“劈叉”曲线，表明频响曲线在共振频率附近产生“劈叉”的原因是正交方向弯曲振动模态的干扰。提出了针对“劈叉”曲线的实验数据处理方法。利用阻尼层模量识别过程判断出“劈叉”曲线上两峰对应的振动方向，辨别主共振峰和干扰峰。进而分析了“劈叉”曲线干扰频率与幅度等对试件损耗因子识别精度的影响，结果表明：在主共振峰可辨条件下，使用弯曲共振法常规计算公式，即可得到相当准确的结果。本文研究可用于解决“劈叉”曲线数据处理的难题。
Abstract
On a frequency response curve,sometimes,there is a resonance peak splitting to two peaks when measuring damping coefficient of a composite specimen with the flexural resonance method,it is called the “Double-Peak” phenomenon.Here,the coupled vibration model of a cantilever beam specimen excited from different directions was established.The “Duble-Peak”curve was recovered through signals composition.It was shown that the “Double-Peak” phenomenon is caused due to interferences of the orthogonal flexural vibrating modes for the two peaks,one is the principal resonance peak,the other is the interfering peak.Based on this mechanism,the method to identify the principal resonance peak and the interfering peak by identifying the modulus of the damping layer was proposed.The effects of frequency,and amplitude,etc.of interference signals on the identification accuracy of the specimen′s loss factor were analyzed.The results showed that quite accurate results can be obtained with the flexural resonance method despite the existence of the interfering peak if the principal resonance peak can be identified.The study results provided a way to deal with the “Double-Peak” curve and data.
关键词
弯曲共振法；共振峰；&ldquo /
劈叉&rdquo /
；损耗因子
{{custom_keyword}} /
Key words
flexural resonance method /
resonance peak /
“Double-Peak” /
loss factor
{{custom_keyword}} /
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 戴德沛. 阻尼减振降噪技术[M]. 西安：西安交通大学出版社，1986.
Dai De-pei. Damping techniques in noise and vibration control[M]. Xi’an: Xi’an JiaoTong University Press, 1986.
[2] 侯宏，余虎，孙亮. 基于共振法的黏弹性细棒力学参数宽频测试[J]. 振动与冲击，2015，34(9)：107-110.
Hou Hong, Yu Hu, Sun Liang. Determination of dyanmic parameters of viscoelastic thin bar using resonance measurement method under pulse excitation[J]. Journal of vibration and shock, 2015, 34(9): 107-110.
[3] Oyadiji S O, Tomlinson G R. Characterization of the dynamic properties of viscoelastic elements by the direct stiffness and master curve methodologies, part 1: design of load frame and fixtures[J]. Journal of sound and vibration, 1995, 186(4): 623-647.
[4] 王超，吕振华. 粘弹性阻尼材料力学参数测试实验用双边附加自由结构阻尼试件设计方法研究[J]. 振动与冲击，2014，33(5)：101-108.
Wang Chao, LÜ Zhen-hua. Research on the design of specimens damped both sides used in the measurement of viscoelastic material’s mechanical parameters[J]. Journal of vibration and shock, 2014, 33(5): 101-108.
[5] ASTM 2010 E756-05. Standard Test Method for Measuring Vibration-Damping Properties of Materials[S]. American National Standards Institute, 2010.
[6] 谭祖根，陈守川. 电涡流传感器的基本原理分析与参数选择[J]. 仪器仪表学报，1980，1(1)：113-122.
Tan Zu-gen, Chen Shou-chuan. The analysis and Parameter selection on the fundamentals of eddy current transduces[J]. Chinese Journal of Scientific Instrument, 1980, 1(1): 113-122.
[7] Read B E, Dean G D 1978 The determination of dynamic properties of polymers and composites[M]. Bristol: Adam Hilger, 1978.
[8] 杜功焕，朱哲民，龚秀芬. 声学基础(第二版)[M]. 南京：南京大学出版社，2001.
Du Gong-huan, Zhu Zhe-min, Gong Xiu-fen. Fundamentals of Acoustics(2nd ed)[M]. Nanjing: Nanjing University Press, 2001.
[9] Liao Y, Wells V. Estimation of complex Young’s modulus of non-stiff materials using a modified Oberst beam technique[J]. Journal of sound and vibration, 2008, 316(1): 87-100.
[10] 苟文选. 材料力学(上卷)[M]. 西安：西北工业大学出版社，2000.
Gou Wen-xuan. Mechanics of Materials(Vol. 1)[M]. Xi’an: Northwestern Polytechnical University Press, 2000.
{{custom_fnGroup.title_cn}}
脚注
{{custom_fn.content}}
PDF(1214 KB)
