Student Name: Hajira Aftab
Research Topic: Damage identification of nonlinear breathing cracks under different excitations
Supervisor: Dr. Ummul Baneen
Current Progress: Completed-2021
Description
The research area aims to identify breathing cracks in 2D (plate-like) structures using different excitations like impulse, harmonic and random. The breathing cracks are small cracks that open and close under vibration, hence exhibiting nonlinear phenomenon. In this study, an analytical model of nonlinear breathing cracks has been developed by employing the Kirchhoff-Love plate theory and the Method of Multiple Scales. The opening and closing of the part-through central crack is modeled by using piecewise equations with positive half of the response signal to the opening of crack and negative half to the crack closing. For identification and severity estimation a percentage frequency change is proposed. The proposed method is tested in simulation as well as through experiments on an aluminum plate under different excitations which proved the robustness of the method. The proposed method is base-free and effective regardless of the type of excitation.
The study on breathing cracks in a plate has a huge scope as it is just an initial stage in identifying the crack. The localization of crack can be done in the future both mathematically and by simulations. The breathing crack at different angles and positions can also be investigated.
Publications
- Aftab, H., Baneen, U., & Israr, A. Experimental investigation of a breathing crack in a plate under different excitations. Structural Control and Health Monitoring, e2922.
- Aftab, H., Baneen, U., & Israr, A. (2021). Identification and severity estimation of a breathing crack in a plate via nonlinear dynamics. Nonlinear Dynamics, 104(3), 1973-1989.