基于国际平整度指数IRI的飞机动载系数分析

Aircraft Dynamic Load Coefficient Based on International Roughness Index

为分析道面不平整引起的动载作用,研究了国际平整度指数(International roughness index,IRI)与道面功率谱密度(Power spectral density,PSD)的关系,并通过建立四分之一飞机振动模型,分析了飞机作用于道面上的动载特性,建立了基于概率的经空气动力修正后的动载系数分析模型,最后以某机型为例对动载系数影响因素进行讨论。结果表明:动载系数随速度增加呈先增大后减小的趋势;道面平整度等级是影响飞机对道面动力作用的最关键因素;飞机重量与升力影响因子(Lift impact factor,LIF)呈非线性关系,因此动载系数随飞机重量的增加呈非线性变化;飞机高速滑行时动载系数随飞机重量变化的离散程度较大,此时随飞机重量增加,飞机对道面的动力作用增大;动载系数随机轮轮胎刚度、机身缓冲系统阻尼及刚度的增加近似呈线性变化,机身缓冲系统阻尼增大,动载系数则减小;机轮轮胎刚度及机身缓冲系统刚度增大,动载系数则增大。

In order to analyze the dynamic load caused by uneven airport pavement,the relationship between international roughness index（IRI）and power spectral density（PSD）of airport pavement is studied.The dynamic load characteristic based on aircraft-pavement interaction is analyzed by building a quarter aircraft model,and a probability-based analysis model of dynamic load coefficient under aerodynamic correction is established.Finally,taking a certain aircraft type for example,the influence factors of dynamic load coefficient are discussed.The results indicate that the dynamic load coefficient increases at first and then decreases with the increase of velocity.The grade of airport pavement roughness is the most critical factor influencing the dynamic effect of aircraft on pavement.The relationship between aircraft weight and lift impact factor（LIF）is nonlinear,so the change of dynamic load coefficient with the increase of the aircraft weight is nonlinear.When the aircraft is taxiing at a high-speed,the discrete de-gree of dynamic load coefficient changing with aircraft weight is greater,and as the aircraft weight increases,the dynamic effect of aircraft on pavement increases.Dynamic load coefficient approximatively linearly changes with the increase of the stiffness of aircraft wheel tire,damping and stiffness of fuselage buffer system.The damping of fuselage buffer system increases,then the dynamic load coefficient decreases.The stiffness of aircraft wheel tire and fuselage buffer system increases,then the dynamic load coefficient increases.