大型固定翼民用飞机系留载荷非线性计算分析

Non-linear analysis of mooring load for large fixed-wing civil aircraft

采用有限元法,充分考虑了固定翼民用飞机机体结构刚度分布对超静定问题求解的影响、起落架缓冲支柱"行程-载荷"之间的非线性关系、系留绳索单向承力特性以及起落架与地面之间的接触非线性,建立了大型固定翼民用飞机系留载荷计算模型并给出了相应计算流程;计算分析了风载作用方向、飞机重量、起落架机轮与地面摩擦系数、系留绳索刚度对飞机系留载荷的影响规律。分析发现:风载方向与航向平行(不平行)时,系留载荷较小(较大);由摩擦系数和飞机重量变化所引起最大系留载荷的差异分别为9%和35%,摩擦系数对最大系留载荷存在一定影响,而飞机重量对其影响显著;飞机重量越小,则最大系留载荷越大,在计算系留载荷时需要考虑可能的最小飞机重量;系留绳索刚度越大,则系留载荷越大,但飞机最大位移越小,在选取系留绳索材料时应同时考虑系留载荷和系留作用下飞机最大位移。

Based on finite element method, effect of the airframe stiffness distribution on the statically indeterminate problem, the nonlinear relationship between load and displacement of the landing gear damper strut, one-way load-carrying characteristics of mooring rope as well as the contact between the landing gear and the ground are taken into account, the calculation model of mooring load and the corresponding procedure are established. Effects of wind direction, aircraft weight, friction coefficient and the modulus of mooring rope on the mooring load are investigated. It is found that, the differences of the maximum mooring loads due to the variations of friction coefficient and aircraft weight are 9% and 35%, respectively. Small aircraft weight leads to large maximum mooring load, and therefore the load condition of the possible minimum aircraft weight needs to be taken into account. Both mooring load and maximum aircraft displacement need to be considered when selecting the material of mooring rope.