带裂纹旋转柔性梁系统的刚柔耦合动力学研究

对具有刚柔耦合效应的带裂纹旋转柔性梁进行建模和动力学特性分析研究。采用晶格弹簧离散模型,利用无质量弹簧模拟梁上裂纹,通过考虑梁变形的二阶耦合项建立了带裂纹旋转柔性梁系统的一次近似耦合动力学控制方程。数值计算结果表明,裂纹的存在会使旋转柔性梁的固有频率降低,并且随着梁转速的增大,这种降低效应呈减弱趋势;值得注意的是,裂纹梁的固有频率与裂纹处的弯矩具有正相关关系。此外,裂纹的存在不仅会使转速变化阶段梁的末端位移响应增大,还会对转速稳定后梁的末端振荡产生显著的影响。

Rigid-flexible coupling dynamic analysis of a rotating flexible beam with cracks

The effect of a crack on the dynamic behaviors of a rotating flexible beam system with rigid-flexible coupling effect is investigated through the application of a lattice spring model (LSM).Based on the local flexibility theory of cracks,the flexural stiffness of the cracked section is represented by a massless rotational spring,and then the first-order approximate coupling model of the rotating flexible beam is established,which takes account of the nonlinear coupling between transverse and longitudinal deformations.Numerical results show that the presence of the crack lowers the natural frequencies of the rotating flexible beam,and as the rotation speed of beam increases,the impact of the crack on the natural frequencies becomes weakens.In particular,a positive correlation between the natural frequencies and the bending moment at the crack is discovered.In addition,the crack can not only increase the response at the beam tip during the stage of rotation speed increase,but also has a significant impact on its oscillation amplitude during stable rotation.