基于扭摆的中低频响应谱修正方法研究

冲击响应谱广泛应用于舰艇及其舰载设备抗冲击的设计工作中。由于趋势项误差的存在使得冲击谱中低频区出现失真现象，为此通过理论分析解释了趋势项误差对冲击谱中低频区域测量失真的作用机理，得到了零飘现象中放大倍率与系统频率和系统响应间的关系。从原理上分析阐述数学修正方法的优劣，结合现有修正仪器提出扭摆模型修正方法，建立该扭摆模型振动方程并应用Ritz-Galerkin方法推导近似周期解与主共振频率方程。进行了扭摆与传统弹簧振子在相同冲击环境下冲击响应试验，结果表明，在低频扭摆冲击响应摆角小于20.06°范围内，扭摆与弹簧振子具有良好的线性关系。对比数学修正方法、传统弹簧振子修正方法以及扭摆修正方法发现，扭摆修正方法对冲击谱中低频段的修正结果可信度较高。

Correction Method of Low and Medium Frequency Shock Response Spectra Based on New Measuring Device

The shock response spectrum is widely used in the design of ship and its shipborne equipment for impact resistance. Because of the existence of the trend term error, a distortion always occurs in the low frequency region of the shock spectrum. The effect mechanism of trend term error on measurement distortion in the low frequency region of shock spectrum was explained through theoretical analysis. The relationships between the magnification in the zero drift phenomenon with the natural frequency of system and the response of system were obtained. And the advantages and disadvantages of mathematical correction methods are analyzed. A new correction method of torsion pendulum correction model is proposed for the existing correction instrument, and a vibration equation of torsion pendulum model is established. And the approximate periodic solution and the main resonance frequency equation of torsion pendulum are derived by using the Ritz-Galerkin method. The maximum shock responses of the torsion pendulum and the traditional spring-mass-oscillator under the same impact environment was theoretically analyzed and test. The results show that the torsion pendulum has a good linear relationship with the spring-mass-oscillator within the swing angle of low frequency torsion pendulum less than 20.06°. By comparing the methematical correction method, traditional spring vibrator correction method and torsion pendulum correction method, it is found that the torsion pendulum has high reliability for correction results of low frequency region in the shock spectrum. Key