Assessment of nonlinear structural response in A400M GVT

Abstract

As part of the flutter clearance and aircraft certification process, a Ground Vibration Test (GVT) was performed on the first Airbus A400M out of production line. The A400M is a military transport aircraft with a maximum take-off weight of 141 Tm and capable of take off and landing on unprepared runways. Its powerplant is formed by four TP400 turboprop engines with a combined power of 44,000 SHP. With the A400M being a relatively large four-engine aircraft, its structural dynamic response is characterized by a considerably rich modal density in the frequency range of interest of the test, up to 30 Hz. The pylon-mounted turboprop engines are more flexible that alternative motorizations, contributing to an even denser modal base. Following usual practice, most relevant modes, including those of powerplant and control surfaces, were appropriated (tuned) at different excitation levels. This allowed assessing the magnitude and character of structural nonlinearities inherent to real structures. Selected results are presented in this document together with some of the lessons learned. (Figure Presented) ©2010 Society for Experimental Mechanics Inc.