松拉金成组叶片动应力分析

DYNAMICAL STRESS ANALYSIS FOR LOOSE LASHING WIRE GROUPED BLADES

提出了采用瞬态动力分析计算松拉金成组叶片动应力的方法。首先采用瞬态动力分析与最大熵谱分析相结合的方法计算松拉金成组叶片的动频,然后采用频率扫描法,在叶片上加上频率与成组叶片一阶动频相同,以及高于一阶动频1 Hz和低于一阶动频1 Hz的简谐载荷,进行松拉金成组叶片的瞬态动力分析,求得结构在共振载荷作用下的瞬态动力响应后,再在其位移峰值点进行子结构的扩展分析,求得叶片的动应力。这样通过频率扫描,求得叶片的动应力曲线。提出的方法未对松拉金与叶片的连接作任何简化和假定,直接建立松拉金与叶片间的摩擦接触模型,该模型真实地反映了松拉金成组叶片中拉金与叶片相互作用的特性,对此模型进行瞬态动力分析,计算其动应力,其计算结果更为真实、可靠,为松拉金成组叶片动应力计算提供了一种准确、可行的数值计算方法。

An algorithm to calculate the dynamical stress of loose lashing wire grouped blade with transient dynamical analysis method is proposed. First, the algorithm calculates the dynamical frequency of loose lashing wire grouped blade by means of the method of transient dynamical analysis combining with maximum entropy spectrum analysis. And then, three groups of harmonic loads, the frequency of them are equal to the first order dynamical frequency, 1 Hz more and 1 Hz less than the first order dynamical frequency, are applied to the blades. After that, the transient dynamical response of blades tothe three groups of resonance vibration loads are calculated respectively, and the dynamical stresses are obtained by using the expansion calculation at the peak points of displacement curves. No any simplification and assumption for the connection of loose lashing wire and blades are used in the proposed algorithm. A frictional contact model for loose lashing wire and blades is constructed directly, and the model reflects the actions of loose lashing wire and blades. The calculated result of dynamical stress is reasonable and reliable. The proposed algo-rithm provides a useful numerical calculating method for the calculation of dynamical stress of loose lashing wire grouped blades.