The first millisecond of the vibration of the stiffened shell, which corresponds to the fuselage of a small passenger airplane; the strike falls on the intersection of the stiffeners
The Movie show numerical simulation of the vibrations of the stiffened and unstiffened closed shells. Parameters of the shell and stiffeners correspond to the light-airplane fuselage with a radius R = 1.3 m, a thickness of aluminum skin of 1.2 mm, a distance between the frames of 0.45 m, and a distance between stringers of 0.145 m. The number of trigonometric vibration forms in the calculation is limited to 224 × 448 in the circumferential and longitudinal directions. All the vibration eigenfunctions with a frequency up to 5 000 Hz are taken into consideration. The tangential inertial terms are taken into account; all the eigenfunctions of longitudinal vibrations are truncated.