基于疲劳寿命的民用飞机舱门止动块允许间隙

止动块是民用飞机舱门重要的结构零件,它通过面-面接触将舱门受到的增压载荷传递至机身门框,止动块结构的可靠性对飞行安全至关重要。 对于面-面接触问题,接触间隙影响载荷分配,同时零件寿命对载荷变化非常敏感,已有研究中缺少间隙对止动块载荷以及疲劳寿命的影响。 以某型飞机的舱门止动块为研究对象,建立舱门-门框的精细网格有限元模型,模型中使用线性间隙法模拟止动块间隙以及超单元法优化计算时长;提出止动块间隙的数学描述方法,采用蒙特卡洛模拟分析间隙对止动块载荷的影响;利用细节疲劳额定值( detail fatigue rating,简称 DFR)法分析疲劳寿命随止动块间隙的变化规律,给出目标寿命下允许间隙的设计方法,可以为舱门止动块间隙设计提供参考。

Allowable clearance of door stops for civil aircraft based on fatigue life

Door stops are important structure parts in civil aircraft, which transfer the pressurized load from door to frame through face-to-face contact. The reliability of door stops is quite crucial for flight safety. For the face-to-face contact problem, contact clearance affects the load distribution, meanwhile the life is very sensitive to the load variation. The influence of clearance to the load and fatigue life of door stop is lacking in previous studies. In this paper, the door stop of some aircraft was studied. The detailed finite element model was established, in which the linear gap and the superelement method were introduced; the mathematical approach describing the clearance randomness was proposed, and the Monte Carlo simulation was carried out to analyze the influence to the stop load; the fatigue life varying with clearance was computed using DFR method, the design approach of allowable clearance under target life was proposed. The work of this paper can provide a reference for the clearance design of door stop.