Fatigue Testing and Analysis of Aircraft Structure Subjected to Aerodynamic and Buffet Loads
The aircraft structures,especially some unique ones like canards,vertical fins and stabilizer fins,are always in dynamic environment during the service life.The structures sustain not only aerodynamic loads but always the buffet loads,the combined effect will make structures accelerated damage and the new damage modes also appear.So studying the combined loading mode and its feasibility is necessary.Aimed for this,the design and implementation of the test rig developed to verify the feasibility of the testing would be detailed in this paper.A cantilever beam utilizing a rectangular tube section was chosen as the article,a steel plate was attached to the free end of the cantilever to support the airbags.A new airbag loading system other than the more conventional hydraulic loading system was used to apply the distributed aerodynamic loads.The buffet loads were applied by high powered,high displacement electromagnetic shakers,and the Hydrostatic Spherical Coupling(HSC)was used to connect the shaker and the cantilever beam.The airbags loading would lead to the bending deformation of the cantilever beam,and the Hydrostatic Spherical Coupling was used to transmit dynamic loads while allowing angular misalignment to ensure the test proceed normally and protect the shaker from damage due to misalignment or angular motion.The energy also could be delivered completely by using the Hydrostatic Spherical Coupling.The new test methodology would be also explored through the dynamic response testing of the cantilever beam while the static loads or the conventional fatigue loads were loaded on it.And the conclusions can be drawn that: 1)The first three frequencies of the cantilever beam with airbag pairs loading static loads or conventional fatigue loads were compared with its inherent frequencies.It can be seen that the frequency change rates during 5 different loading conditions changed within 4%,that means the loading airbags would not change the structure inherent dynamic characteristics largely and the loading environment simulated here is close to the reality; 2)Compared with the first two frequencies,the third frequency changed more when loading the same static loads or conventional fatigue loads,almost 3 times of them.3)The number and the configuration of the loading airbags influenced the dynamic response(the natural frequency and the acceleration magnification)of the structure,the pressure reservoir should be added and the reasonable load position should be selected to decrease the influence of the airbags to the structural dynamic characteristics.This new coupling method of aerodynamic loads and the buffet loads would supply the basic technology for the large-scale test and the complicated test of this kind.
aerodynamic loads buffet loads coupling loading dynamic response testing
Li Yixuan Zhang Zhijun Shao Chuang
Laboratory of Aeronautical Acoustics and Dynamics,Aircraft Strength Research Institute,Xian 710065,China
国际会议
2014 Asia-Pacific International Symposium on Aerospace Technology(2014亚太航空航天技术学术会议)
上海
英文
1-8
2014-09-24（万方平台首次上网日期，不代表论文的发表时间）