摘要
从模态识别基本原理出发,对脉冲激励下的时-频域响应、谐振激励下的时域响应的表达式进行推导,找到了其时-频域下的幅值关系,认为一定条件下谐振响应中伴随自由振动成分短时间内难以衰减,指出谐振激励力幅值与脉冲力幅值相等时,脉冲响应频谱对应频率下的幅频与谐振下的强迫振动幅值相等。在建立响应等价关系的基础上,推导了仅通过脉冲响应频谱上有限个谱线信息所确定的某阶模态阻尼比的计算公式。利用船体梁模型验证了响应预报及阻尼比估算的准确性。完成了2块不同材料典型船体板单元模型的前8阶模态阻尼比测试,通过数值计算结合试验响应频谱验证了方法的快速性、可靠性。
Starting from the basic principle of modal identification and the expressions were derived for time frequency response of the excitation force and time response of resonant excitation,and the relationships among the time-frequency domain amplitudes were found.It was concerned that the associated free vibration in the resonant response is diffeult to decay in a short time,and it was pointed out uhat the amplitude of the impulse frequency response spectrum at cresponding frequency is equal to the amplitude of forced vibration under resonant exitation.Based on establishing relationship of response equivalence,the formula of damping ratio was derived by a limited spectral information of impulse responses pectrum The acurmcy of response prediction and damping ratio estimation was venfied by ship girder model.In adtion,the first eight modal damping ralios tests of2 tpical ship plate element models of diferent materiala were also completed,and the rapidity and elabilily of the mehod were verified by the numeral caleulation binding experimental response frequency spetrum.
作者
唐宇航
陈志坚
梅志远
TANG Yuhan;CHEN Zhijia;MEI Zhiyuan(Department of Naval Architecture Engineering,Naval Universily of Engineering,Wuhan 430033 China;Naval Rescarch Institute,Beijing 100161,China)
出处
《国防科技大学学报》
EI
CAS
CSCD
北大核心
2017年第6期79-87,共9页
Journal of National University of Defense Technology
基金
国家自然科学基金资助项目(51479205)
关键词
脉冲激励
谐振激励
响应频谱
模态阻尼比
伴随自由振动
快速预报
impulse exciation
resonant exitation
response petrum modal damping ratio
asseiated free vibration
fast prediction
