裂纹齿轮动力特性三维有限元模拟

建立了裂纹齿轮结构的三维有限元动力学模型,分析了齿轮轮齿发生裂纹后的齿轮动力特性(固有频率、振型、动态应力等),并对裂纹出现位置和裂纹尺寸等对齿轮动力特性的影响进行了深入探讨和计算机模拟。指出裂纹尺寸和位置对于齿轮的固有频率和振型都有影响,当出现裂纹后固有频率发生下降,振型也发生变化,而裂纹位置对固有频率和振型影响大于裂纹尺寸的影响,当裂纹位于齿根处时齿轮固有频率下降较大,当裂纹位于齿顶处时齿轮固有频率下降较小,当裂纹出现后齿轮体的振型明显不同于无裂纹时的振型,在裂纹附近振动的振幅增大,并且齿轮体的动态应力也发生变化,与无裂纹的齿轮结构动力特性完全不同。

3-Dimensional FEM Simulation of Dynamic Characteristics of Cracked Gear

The 3-dimensional FEM dynamic model of a cracked gear structure is established,the dynamic characteristics,i.e.,the natural frequency,the mode shape,the dynamic stress and so on,due to crack of gear tooth are analyzed in this paper.The influence of crack position and crack depth etc.on dynamic characteristics of gear is investigated by using computer simulation and the FEM.It shows that the influence of crack depth and crack position on both natural frequency and mode shape of gear is significant.The natural frequency drops and mode shape changes when a crack started.This natural frequency drops with the increase of crack depth,but the influence of crack position on both natural frequency and mode shape is greater than that of the crack depth.The natural frequency of gear drops more when crack locate at the tooth root in comparison with that of the gear when crack appears at the tooth tip.When a crack starts,the mode pattern of gear structure becomes very different from that of g gear uncracked.when a crack starts.The amplitude is augmented and the dynamic stress of gear changes in the crack neighborhood.The present study is important and usuful for damage detection and fault diagnosis.