Test Research and Finite Element Analysis on Extension Performance of Civil Aircraft Flaps Subjected to Extreme Temperature

Aircraft climate test was conducted to investigate the effect of extreme temperature on extension performance of civil aircraft flaps in aircraft climate laboratory. Test results show extending the flaps to 10° requires 9.5 s, 7.8 s, 7.6 s when the standard equipped aircraft was kept at −40 ℃, 20 ℃ and 40 ℃ for the stipulated time, respectively. The lower the temperature is, the more difficult it is to extend the flaps. Furthermore, a finite element analysis (FEA) mode of the flap motion mechanism was proposed to reveal the influence of extreme temperature on deformation and drive torque of the flaps. Actual motion law of flap motion mechanism was adopted to describe behavior of flap motion mechanism under extreme temperature. The numerical research shows the drive torque decreases from −0.51 × 10⁴ to −4.52 × 10⁴ N mm when temperature rises from 20 to 74 ℃; conversely the drive torque increases from −0.51 × 10⁴ to 27.5 × 10⁴ N mm when temperature drops from 2 to −55 ℃. In addition, the lower the temperature is, the more obvious the deformation mismatch of the flap mechanism is, which may cause the friction to increase. The increasing friction due to the temperature drop results in the higher drive torque required to extend the flaps, which is also the reason that the time for extending the flaps to 10° increases with the decrease of temperature. The numerical results are observed to mutually agree with the test results mentioned above that the low temperature makes it difficult to extend the flaps.