滑橇式直升机地面共振机体动力学特性研究  

Fuselage dynamic features of skid helicopter ground resonance

作　　者：吴靖 胡国才 刘湘一 WU Jing;HU Guocai;LIU Xiangyi(Aeronautical Foundation College,Naval Aviation University,Yantai 264001,China)

机构地区：[1]海军航空大学航空基础学院

出　　处：《振动与冲击》2019年第21期216-220,264,共6页Journal of Vibration and Shock

摘　　要：为研究机体设置阻尼器后非比例阻尼对滑橇式直升机机体动力学特性的影响,建立了支持在滑橇式起落架上的直升机机体有限元模型。给出了结合有限元法的直升机机体固有频率和当量至桨毂中心的质量、刚度及阻尼的计算方法,当量后的比例阻尼系统与实际非比例阻尼系统的复特征值相同。分析了非比例阻尼对机体模态频率及阻尼的影响:由于非比例阻尼的影响,使得模态频率随阻尼器阻尼的增加而增加,而在阻尼器阻尼较大时,模态阻尼可能减小,不利于直升机地面共振动稳定性;计入阻尼器阻尼关于速度的非线性后,机体模态频率随阻尼器速度的增加先增加后减小,模态阻尼不是按照阻尼器阻尼随其速度的变化趋势而变化,而可能出现两次增加再减小的过程,在阻尼器定压活门开启前后各形成一个峰值。A finite element(FE) model of helicopter fuselage supported by skid landing gear was established to study effects of non-proportional damping on fuselage dynamic features of a skid helicopter with damper. The FE calculation methods for helicopter fuselage natural frequencies and equivalent mass, stiffness, and damping from fuselage to rotor center were derived. Complex eigenvalues of the equivalent proportional damping system and the actual non-proportional damping system were the same. The effects of non-proportional damping on fuselage modal frequency and damping were analyzed. It was shown that due to non-proportional damping, modal frequencies increase with increase in damper’s damping;when damper’s damping is larger, modal damping may be decreased to be unfavorable to stability of helicopter ground resonance;after considering the nonlinear relation between damper’s damping and its velocity, fuselage modal frequencies increase firstly and then decrease with increase in damper velocity;modal damping doesn’t change according to variation trend of damper’s damping with variation of damper velocity, it may have a process with 2 increases and one decrease;modal damping has 2 peak values, one appears before damper constant pressure valve opening and one does after.

关 键 词：直升机 滑橇起落架 液压阻尼器 地面共振 固有频率 模态阻尼 非比例阻尼 

分 类 号：V275.1[航空宇航科学与技术—飞行器设计]