机械式超低频振动台设计与振动特性研究

为获得一种结构简单、运行稳定且成本低的超低频振动装置,采用机械运动机构中常见的曲柄连杆机构设计了一种机械式超低频振动台,对其结构设计和振动特性进行了详细的说明和理论分析。采用激光多普勒测振仪对实际振动台装置的振动特性进行了测试和验证。结果表明:振动台的实际振动特性符合理论计算结果,振动加速度幅值与振动频率的平方成线性关系且存在二倍频分量。但在工程应用中,本振动台装置可通过调节相关参数如连杆比来降低二倍频的影响程度,进而认为其能够提供3 Hz以内的振动激励源,最终通过典型应用实例验证了机械式超低频振动台的实用性。

Design of a Mechanical Ultra-low Shaking Table and its Vibration Characteristic Study

In order to obtain an ultra-low shaking device with simple structure, stable operation performance and low cost advantages, a kind of crank-connecting rodcommonly used in mechanical motion mechanisms was selected to design the above mechanical ultra-low shaking table. The design and shaking performances were thoroughly explained and analyzed, a laser Doppler vibrometer was selected to measure the vibration velocity signal of the practical shaking table for comparison and validation. The experimental results agreed well with the theoretical calculations: the amplitude of vibration acceleration was proportional to the squared vibration frequency and the second-harmonic ripple was existed in the acceleration signal. However, in the engineering applications, the designed shaking table could minimize the effect of second-harmonic ripple through adjusting the ratio of crank-connecting rod, which had the possibility to provide the standard ultra-low vibration sources within 3 Hz. Finally, the practicability of the mechanical ultra-low shaking table was validated by a classical application example.