连铸结晶器非正弦振动共振分析

根据谐波共振理论，连铸结晶器做非正弦振动且振频低于振动机构自然频率时，由于谐波频率是振频的整数倍，一部分幅值较大的谐波可引发共振.利用傅里叶变换对连铸结晶器非正弦振动加速度函数进行谐波分析，得该波形谐波幅值与振幅、振频、非正弦因子和谐波阶数的变化关系，从理论上给出一种削弱共振的方法.当结晶器振动机构的自然频率已知时，不同振频下可引起共振的谐波阶数是确定的.通过谐波幅值与各振动参数的变化关系，得到不同振动参数组合对应的谐波幅值.采用谐波幅值较小的振动参数组合，可削弱共振现象对连铸结晶器振动机构的不利影响，减小结晶器偏摆量，维持钢液液面稳定，改善连铸机工作状况.

Resonance Analysis of Non-sinusoidal Oscillations of Continuous Casting Mold

According to the harmonic resonance theory， when the continuous casting mold is non-sinusoidal oscillation and the vibration frequency is lower than the natural frequency of the oscillator in the mold， partial harmonics with a higher amplitude can lead to resonance because the harmonic frequencies is an integer multiple of the oscillation frequency， which can directly affect the quality of slab. Using Fourier transformation， the acceleration curve of non-sinusoidal oscillation of the mold is analyzed and the relationships between harmonic amplitude and other factors， such as initial amplitude， oscillation frequency， non-sinusoidal oscillation factor and harmonic order are obtained. Then， a theoretical method of restraining resonance can be given. When the natural frequency of the oscillator in the mold is known， the harmonic order of resonance under different oscillation frequencies is determined. The harmonic amplitude corresponding to the combination of different oscillation parameters can be given by the relationship between the harmonic amplitude and the variation of each oscillation parameter. Consequently， selecting an oscillation parameter combination with a smaller harmonic amplitude can reduce the adverse effect of resonance phenomenon on the oscillator in the mold， resulting to reduce the deflection of mold， maintain liquid level stabilizing and improve the working conditions of continuous casting machine.