Non-linear vibration method for detection of fatigue cracks in aircraft wings

Some results of mathematical simulations of bending vibrations encountered in a cracked aircraft wing under external harmonic excitation are presented. It is shown that due to the influence of the elastic non-linearity of typical cracks, superharmonic vibration regimes appear in the system response. By utilizing specific features of these regimes a new vibration method for the detection of cracks is developed, and an original procedure for transformation of the non-linear elastic properties of the damaged cross-section is proposed. Unlike traditional procedures the vibration method proposed herein shows capability of high detection sensitivity and testing reliability. (C) 2000 Academic Press.