13th International Conference on Fracture June 16–21, 2013, Beijing, China -2- 2. Experimental Procedure 2.1 Laser shock peening Two experimental set-ups to evaluate the effects of water temperature and water thickness layer are shown in Fig. 1(a) and 1(b), respectively. A target sample was A7075 aluminum alloy with demensions of 50 × 50 × 10 mm.A Q-switched Nd:YAG laser with a wavelength of 532 nm and a pulse width of 3 – 5 ns was used for both experiments. A laser beam was focused to the center of sample using lens. The laser was irradiated at least two times for each test. In set-up of Fig. 1(a), experiment was conducted with varying laser energy and water temperature. In set-up of Fig. 1(b), experiment was conducted with varying the thickness of water layer on a target sample. The detail of experomental conditions are shown in Table 1. 5 mm Water Lens AE sensor Sample Rubber board (a) Acrylic tank 150 mm×150 mm×155 Nd:YAG laser CWM Nd:YAG laser Mirror Lens Sample Sensor Rubber board Acrylic tank 110 mm×110 mm×115 Acrylic board Figure 1. Schematic of experimental set-ups for studying effects of (a) water temperature and (b) water layer thickness CWM Water layer (b)
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