DESIGN OF VIBRATION DAMPING DEVICES FOR AIRCRAFT AERODYNAMIC SURFACES

VIBRATIONS ARE AN INHERENT PROBLEM FOR AIRCRAFT STRUCTURES, ESPECIALLY MILITARY AIRCRAFT THAT PERFORM HIGH-SPEED MANEUVERS CAUSING EXTREME ACCELERATION LEVELS. A FORM OF UNWANTED VIBRATION REFERRED TO AS BUFFET OFTEN OCCURS WHEN A SURFACE OF AN AIRCRAFT IS DIRECTLY EXPOSED TO AN UNSTEADY, VORTEX FLOW GENERATED UPSTREAM DURING HIGH-ANGLE-OF-ATTACK MANEUVERS. IN THE CASE OF CERTAIN FIGHTER AIRCRAFT, FOR EXAMPLE, BUFFETING OF THE TWIN VERTICAL STABILIZERS EXCITES THE BENDING AND TORSIONAL MODES OF THESE STRUCTURES, AND, OVER TIME, FATIGUE FAILURES OCCUR. AIRCRAFT DESIGN IS CONTROLLED BY MANY FACTORS, AND USUALLY VIBRATION PROBLEMS HAVE TO BE SOLVED WITHOUT MAJOR DESIGN MODIFICATIONS; VIBRATION DAMPING IS OFTEN A PREFERRED SOLUTION ESPECIALLY WHEN THE SOURCE OF THE EXCITATION CANNOT BE ELIMINATED. DESIGN CONSIDERATIONS FOR THE DEVELOPMENT OF DAMPING TREATMENTS INDICATE THAT TUNED-MASS DAMPERS ARE MORE FEASIBLE FOR AIRCRAFT AERODYNAMIC SURFACE VIBRATION PROBLEMS THAN OTHER TYPES OF DAMPERS. THIS IS ESPECIALLY TRUE FOR MODIFICATIONS TO EXISTING AIRCRAFT. DAMPING TECHNOLOGY HAS ADVANCED DRAMATICALLY IN RECENT YEARS, AND THE APPLICATION OF PASSIVE DAMPING TECHNOLOGY HAS PRODUCED IMPRESSIVE RESULTS FOR A WIDE RANGE OF STRUCTURES. INCORPORATING DAMPING INTO AIRFOIL STRUCTURES IS A NATURAL PROGRESSION THAT COULD SOLVE CURRENT PROBLEMS AND LEAD TO IMPROVED DESIGNS IN THE FUTURE.