School of Aeronautics, Northwestern Polytechnical University
The deflecting to airflow flap of civil aircraft are generally driven by complex multi-hinge mechanisms in space. According to the requirements of airworthiness clause CCAR25.671, it is necessary to carry out research on mechanism characteristics under typical faults.Firstly, a digital prototype of complex multi-hinge space mechanism is constructed. The multi-point constraint RBE3 element is used to associate the intersection point of the rigid multi-hinge mechanism to the flexible flap body, and the rigid-flexible coupling dynamic model of the flap mechanism is established.Under the three aerodynamic load conditions of cruise, take-off and landing, two typical faults, hinge jamming and single-point failure of the control system, were simulated by adjusting the friction coefficient of the hinge kinematic pair and setting the single-side drive failure.Finally, the variation law of flap driving moment and hinge point load under fault conditions is analyzed. The results show that: when the hinge is jamming,the torque of the inner mechanism will reach 1.57×108 N·mm in 0.8s, and the inner driving link ear piece will be stretched and damaged. When the inner mechanism fails, the driving torque of the outer mechanism increases by 7.5 times, and the maximum radial load of the rocker arm hinge point increases by a maximum of 13.5 times.In practice, we should focus on the radial bearing capacity of the joint bearing in the outer rocker arm of this type of flap to avoid the situation of independent manipulation of the outer mechanism, and at the same time, it is necessary to add torque protection to the entire drive system.