考虑几何非线性和热效应的刚柔耦合系统的频域特性研究

研究温度场中旋转刚体-梁系统的刚-柔耦合动力学特性.考虑几何非线性和热效应,从精确的应变-位移关系式出发,用虚功原理和有限单元法建立了旋转刚体-梁系统的刚-柔耦合动力学方程.由于非线性刚度阵与变形的高次项有关,将非线性刚度阵的各元素表示为广义坐标阵和常值阵的乘积.数值计算表明,该方法可避免重复积分,提高计算效率.在此基础上研究了在温度递增的情况下几何非线性对系统的刚-柔耦合动力学特性的影响,用频谱分析方法研究了系统的固有频率随中心刚体转动惯量和温度的变化.

Study on frequency characteristics of rigid-flexible coupling system considering geometric nonlinearity and thermal effect

The rigid-flexible coupling dynamic characteristic of a rotating hub-beam system in a temperature field was investigated.Considering geometric nonlinearity and thermal effect,based on the exact nonlinear strain-displacement relationship,the rigid-flexible coupling dynamic equations of the hub-beam system were established using virtual work principle and finite element method.Since the nonlinear stiffness matrices are related to the high order terms of deformation,each element of the nonlinear stiffness matrices is expressed as the product of generalized coordinate vectors and constant matrices.Simulation results show that,by using such formulation,duplicated integration can be avoided and computational efficiency can be significantly improved.Furthermore,the effect of geometric nonlinearity on rigid-flexible coupling dynamics in case of temperature increase was investigated.Spectrum analysis method was used to investigate the change of natural frequencies with the moment of inertia of the hub and the temperature.