飞机起落架双腔式油气缓冲器非线性动力学特性研究

Study on Nonlinear Dynamic Characteristics of Double Chamber Oil Pneumatic Shock Absorber of Aircraft Landing Gear

为揭示双腔式油气缓冲器在动态激励下的复杂动力学特性,考虑其气液两相流动,分别建立某起落架双腔式油气缓冲器的动力学数学模型与流固耦合有限元模型,对比分析冲击、正弦激励、随机激励工况下缓冲器的动力学特性。结果表明:双腔式油气缓冲器有限元模型计算结果与数学模型基本一致;在大位移冲击下,等效动刚度呈非线性;在正弦激励下,等效动刚度随激励幅值与频率的变化而变化,并且幅值的改变对缓冲器等效动刚度影响较大。采用流固耦合的方法能够分析油液高速流动下内部复杂流场的问题,更接近实际情况。

In order to reveal the complicated dynamic characteristics of a double chamber oil pneumatic shock absorber under dy⁃namic excitation,the dynamic mathematical model and fluid-solid coupled finite element model of the double chamber oil pneumatic shock absorber were established respectively considered the gas-liquid two-phase flow,and the dynamic characteristics of the shock absorber under shock,sinusoidal and stochastic excitation conditions were compared and analyzed.The results show that the calculation results of the finite element model of double chamber oil pneumatic shock absorber are basically consistent with the mathematical mod⁃el;the equivalent dynamic stiffness is nonlinear under the impact of large displacement;the equivalent dynamic stiffness varies with the excitation amplitude and frequency under sinusoidal excitation,and the amplitude change has a great influence on the equivalent dynamic stiffness of the shock absorb.By using the fluid-solid couped method,the internal complex flow field under high speed oil flow can be analyzed,which is closer to actual situation.