Fathi A. Alshamma,Munaf Hadi Salman,



dynamic crack propagation,stress intensity factor,laser energy,thermal energy,


In this research, for studying dynamic crack propagation behavior in thin plate, a modified method has adopted, when solidification with laser shot peening with cycling thermal effect have done. Since anew a technique is based on an accumulating two types of energies and employments, these together or alone by [Griffith] approach are used to emulate what happen in fuselage with specific conditions in order to study crack velocity and stress intensity factor. The two energies are coming from laser ray and cycling thermal. Analytical model has built with two scenarios for comparing between them. The first one (oven state) when cycling temperatures range for one cycle is from 30 to 150°C and the second (plane path state) when temperature range decreases from 30 to -30 °C  . In addition, the functions (cycling thermal) are functions of duration. Therefore, Fourier series method for periodic functions has built for cycling during path of flight. Oven state for a specific function has assumed with specific shape. Accordingly, simply support condition is adopted for all plates' edges. Laser ray influence has applied according to (P. Peyer & R. Fabbro) equations. For plane path state (cooling), it has been observed that the dynamic crack propagation clearly decreases when the energy of laser was influenced and cycling thermal has increased retardation of crack extension. While for oven state (heating), cycling thermal leads to reducing retardation of crack extension. Also, when comparing between two energies, a high benefit energy is produced from laser (positive effect), and thermal effect depends on state of system if heating or cooling and type of boundary conditions. The values are as well depended on thickness, crack ratio and properties of material


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