This paper considers new damage detection methods, based on utilization of specific vibration effects caused by the distortions of system’s initial symmetry due to appearance of faults. Dynamic behavior of damaged structure under the test harmonic excitation is analyzed using two methods: analogue-digital simulation on specialized computer system and numerical solution with program ANSYS. It is shown that specific distortions of flexural modes and vibration spectrum can be used as diagnostic signs of defects. The main advantage of this approach lies in the more high detection sensitivity in comparison with traditional resonant frequency methods. Further rise of detection sensitivity can be achieved by insertion of additional nonlinear element into the structure of testing object.