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针对水轮发电机组竖向水力振动荷载的复杂性及其通过轴承机架等传递至下机架基础等部位的不明确性,提出了基于正交多项式分解的水力机组动荷载时域识别方法,该方法具有所需测点信息少,识别速度快,避免多次重复正分析试算等优点。同时针对该方法中由模态荷载通过杜哈梅积分得到模态位移的过程中,杜哈梅积分具有时间累积误差的问题,提出了利用正交多项式的正交性质及位移与速度、加速度的导数关系,建立各阶模态位移和模态荷载的关系式,避免了杜哈梅积分计算,提高了计算效率和精度。算例表明,该方法可以有效、方便地识别任意形式时变动荷载。
Aiming at the complexity of vertical hydro-mechanical vibration load of hydro-generator unit and the uncertainty of its transmission from the bearing frame to the base of the lower frame, a method of dynamic load time domain identification based on orthogonal polynomial decomposition is proposed. The method has the advantages of less required measuring point information, fast identification speed, avoiding repeated repeated positive analysis and trial calculation. In the meantime, aiming at the problem of the cumulative error of Duhamel integral in modal displacements obtained by modal loading through Duhamel integral in this method, the orthogonal properties of orthogonal polynomials, the displacement and velocity, the acceleration of Derivative relationship, the establishment of various modal displacement and modal load relationship, to avoid the Duhamel integral calculation, improve the computational efficiency and accuracy. The example shows that this method can effectively and easily identify the time varying loads in any form.