舰载机机身加筋壁板屈曲疲劳试验

Buckling fatigue test of fuselage stiffened panel for carrier-based aircraft

舰载机弹射起飞和拦阻着舰的张力场屈曲波在机身壁板上产生附加的拉伸或弯曲应力,从而显著降低结构疲劳强度、改变疲劳破坏部位。以张力场梁形式的三点弯曲试验开展了反复屈曲下的疲劳特性研究。通过疲劳试验测得的临界屈曲载荷与按工程张力场理论得到的临界屈曲载荷对比,吻合较好。根据3级不同载荷水平下的疲劳试验结果,给出了张力场梁屈曲疲劳试件的无量纲载荷比-寿命曲线及载荷比-张力场系数曲线。根据张力场系数与载荷关系、载荷寿命曲线及飞机寿命指标可控制张力场的严酷程度来开展机身壁板轻量化设计。本项工作为舰载机机身壁板在弹射起飞和拦阻着舰过程中的反复屈曲疲劳问题评定积累了数据。

During the catapult launch and the arrested landing processes for carrier-based aircraft,buckling waves of the tension field at fuselage panel will induce additional tension or bending stress,which significantly decreases the structural fatigue strength and changes the fatigue failure position.The fatigue behavior under repeated buckling is studied through three-point bending test of tension-field spar.The critical buckling load measured from the test matches well with that obtained by adopting the engineering tension field theory.Then,the curves of normalized load ratio vs fatigue life and the curves of normalized load ratio vs tensile field factor are derived from the buckling fatigue test under three different load levels.Finally,the lightweight design of stiffened panel can be realized by controlling the severe level of tensile field based on the relationship between tensile field factor and load and curve of load vs life as well as design service goal of the aircraft.This paper accumulates beneficial data for repeated buckling fatigue evaluation of carrier-based aircraft during the catapult launch and arrested landing.