大型门机在自然风场中的脉动特性研究

Fluctuation Effects of Natural Wind on Large Gantry Crane

大型门式起重机结构轻柔,其固有频率处于低频段,风的脉动效应不容忽视。利用顺风向的Davenport谱与Shinozuka谐波叠加法来模拟脉动风的随机过程,利用FEA方法来分析门机在自然风场中的脉动特性,将其与静载处理结果对照研究:风的脉动效应对结构的最大应力值影响主要体现在非工作状态下,此时支反力大幅波动,整机稳定性受到威胁,而工作状态下由于主梁承受较大工作载荷,风的脉动效应会对主梁结构有较大的振动激励作用,主梁的位移幅值增大较多。

The natural frequency of flexible gantry-crane structure is in the low frequency section, so the pulsation effect of the wind should be valuated. The random process of fluctuating wind is simulated by the Davenport spectrum and Shinozuka harmonic superposition method, and then ANSYS was used to analyze the pulsation response of crane. Comparing the results with that of static loading method suggested that： the fluctuating wind effect on the maximum stress value of the structure is mainly reflected in the non working state. It leads to the counter-force substantial fluctuations so the stability of crane is threatened. But on working condition, because of the girders under heavy working-load, the fluctuating wind effect will vastly promote the vibration of the girders structure, and the displacement amplitude of the girders increases much.