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 difficult to decay in a short time,and it was pointed out that the amplitude of the impulse frequency response spectrum at corresponding frequency is equal to the amplitude of forced vibration under resonant excitation.Based on establishing relationship of response equivalence,the formula of damping ratio was derived by a limited spectral information of impulse response spectrum.The accuracy of response prediction and damping ratio estimation was verified by ship girder model.In addition,the first eight modal damping ratios' tests of 2 typical ship plate element models of different materials were also completed,and the rapidity and reliability of the method were verified by the numeral calculation binding experimental response frequency spectrum.
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