水锤波下简支管路的振动应力及疲劳寿命分析

Vibration stress and fatigue life of simply supported hydraulic line under pulse of water hammer

针对飞机液压管路系统存在的故障失效问题,将水锤波模型应用到液压管路疲劳寿命试验中去,根据地面试验常用的简支支承结构,分析了液压管路在水锤波下的应力变化。首先,开展了无油液管路情况的应力分析,确定出了简支管路中应力最大处的位置;然后由浅入深,建立了管路应力的数学模型,并进行了仿真分析,得出在共振状态下管路将很快被破坏的结果;最后,运用损伤力学对管路的理论疲劳寿命进行了估计。研究结果表明,液压管路理论疲劳寿命随着最大应力及其周期数值的增加而快速下降,与实际液压管路故障失效状况基本吻合。

Aiming at failure problems of aircraft hydraulic pipeline,the model of water hammer pulse was applied to fatigue life test,the variation of stresses of the hydraulic line with the simply supported structure,which was used usually for the ground test of the aircraft hydraulic line,was analyzed under the pulse of water hammer.At first,the stress was analyzed without oil in the line,the place of maximal stress was determined.Further,the mathematical model was built and the stress was analyzed with the simulation,the result of line will soon be destroyed in resonance condition was concluded.At last,the theoretical fatigue life was predicted by applying damage-mechanics.The results indicate that the theoretical fatigue life should be falling fast with the increase of the maximum stress and the period of the maximum stress,and it is consistent with condition of actual hydraulic line failure.