随机激励下新型牵引式悬架系统的P-分岔分析

The P-bifurcation analysis of new traction suspension system with random excitation

针对一种新型牵引式后悬架系统,本文建立了考虑刚度非线性和阻尼非线性的七自由度整车模型;通过分析车身振动位移与加速度的稳态概率密度曲线,研究了改进结构前后的悬架系统的随机P-分岔现象以及路面等级、车速、悬架刚度和悬架阻尼的变化对悬架系统发生随机P-分岔现象的影响。结果表明:改进后的结构发生了随机P-分岔现象;车速、悬架刚度、悬架阻尼的变化与引发悬架系统发生随机P-分岔有关,路面不平度的改变与引发随机P-分岔无关。通过分析车身加速度的概率密度曲线可以看出:改进结构后,汽车平顺性变好;随着悬架刚度、悬架阻尼、车速和路面等级的增加,汽车的平顺性变差。

For a traction type rear suspension system,in this paper,a seven-degree-of-freedom vehicle model considering stiffness and damping nonlinearities is established.By analyzing the steady-state probability density curve of the vibration displacement and acceleration of the vehicle body,the stochastic P-bifurcation phenomenon of the suspension system before and after the improved structure,and the influence of road grade,the velocity,suspension stiffness and suspension damping on the stochastic P-bifurcation of suspension system are studied.The results show that the modified structure has a stochastic P-bifurcation phenomenon;velocity,suspension stiffness and suspension damping can also trigger stochastic P-bifurcation of suspension system,the change of road grade does not trigger a stochastic P-bifurcation.And by analyzing the probability density curve of the body acceleration,it can be seen that the car’s ride comfort improved after the improvement of the structure;with the increase of suspension stiffness,suspension damping,speed and pavement grade,the car’s ride comfort deteriorates.