考虑滑移的螺栓连接动力学建模方法

Dynamics Modeling Method of Bolted Connection Considering Slip

螺栓连接结构受载时经常会出现滑移,这种滑移会影响结构的动力学性能,继而对结构的性能和寿命造成影响。本文以双螺栓连接结构为对象,通过实验和数值仿真手段研究滑移对结构模态特性的影响。实验结果表明,预紧力的增大会导致共振频率上升,而随着激励幅值增大,共振频率下降且每个周期能量耗散量对模态力的梯度增大。基于实验结果,结合考虑滑移的Iwan模型理论,建立非线性动力学模型,应用四阶龙格库塔法进行求解。根据计算结果对宏观滑移情况下的结构模态进行分析,发现此时二阶弹性模态中的共振频率下降量增大,能量耗散量对模态力的梯度降低。该数值计算模型可以很好地表征螺栓连接结构的模态特性,且计算效率高。

Slip often occurs when the bolted connection structure is loaded,and this slip will affect the dynamics performance of the structure,and then affect the performance and life of the structure.In this paper,taking the double⁃bolt connection structure as the object,the influence of slip on the structural modal characteristics is studied by experiments and numerical simulations.The experimental results show that the increase of the preload will lead to the increase of the resonant frequency,and with the increase of the excitation amplitude,the resonant frequency decreases and the gradient of the energy dissipation per cycle to the modal force increases.Based on the experimental results,combined with the Iwan model theory considering slip,a nonlinear dynamics model is established,and the fourth⁃order Runge⁃Kutta method is used to solve it.According to the calculation results,the structural mode under the condition of macro⁃slip is analyzed,and it is found that the resonance frequency drop in the second⁃order elastic mode increases,and the gradient of the energy dissipation to the modal force decreases.The numerical calculation model can well characterize the modal characteristics of the bolted connection structure,and the calculation efficiency is high.