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5.3 LASE SHOCK MICROFORMING EXPERIMENTS
5.3.1 Experimental Setup.
The laser pulse (Nd:YAG laser, wavelength = 1064 nm, pulse length (FWHM) = 9.4 ns) is conducted to the interaction area by means of a reflecting mirror and a focussing lens (biconvex with a focal length of 203.5 mm). In order to obtain a smaller spot size and to reduce the applied pulse energy, a protective mask is placed before the focussing lens. Each specimen was fixed on a holder by means of a computer controlled stage.
The practical irradiation system used for the experiments is photographically shown in figure 5.9. Table I shows the working conditions of the experiments.
The practical irradiation system used for the experiments is photographically shown in figure 5.9. Table I shows the working conditions of the experiments.
Figure 5.9. Laser shock microforming experimental setup used at Centro Laser UPM.
Tabla 5.1. Irradiation Parameters
5.3.2. Experimental results.
In order to study the influence of laser spot position on the net bending angle several experiments were systematically treated at the available experimental facility changing distance d. In figure 10 a SEM photograph of the geometry of the treated specimens is shown together with the representative areas of laser interaction at each particular case.
The deformation of the thin metal strips, see figure 5.11, is measured using confocal microscopy, see figure 5.12.
The observed experimental deformation profiles are in good agreement with the numerical model predictions, as shown in figure 5.13.
In order to study the influence of laser spot position on the net bending angle several experiments were systematically treated at the available experimental facility changing distance d. In figure 10 a SEM photograph of the geometry of the treated specimens is shown together with the representative areas of laser interaction at each particular case.
Figure 5.10. Photograph of processed thin metal Strips with indication of the laser incidence points in three different tests.
The deformation of the thin metal strips, see figure 5.11, is measured using confocal microscopy, see figure 5.12.
The observed experimental deformation profiles are in good agreement with the numerical model predictions, as shown in figure 5.13.
Figure 5.11. Scanning electron microscope (SEM) photographs of the thin metal strips after irradiation.
Figure 5.12. Confocal microscopy image of the thin metal strips alter irradiation.
Figure 5.13. Comparison of numerical vs. experimental deformation geometry for three different experimental conditions (distance from clamping base).
Net bending angle increases as pulse position is closer to d = L/3, and it decreases as it is closer to the free end of the strip.
