Fracture of carbon fiber composite strip under preloading and CW laser irradiation

Carbon fiber composite has been widely used in structural engineering applications, and research on the mechanical properties under various conditions is attractive. The study experimentally investigated the damage effect of CW laser ( λ=1064nm ) on carbon fiber composite strip under preloading. The effects of laser power and preloading on fracture morphology, temperature of the center of the irradiation area and fracture time were investigated. The experimental results show that when the preloading was lower than the fracture threshold, the laser irradiating could cause matrix damaging, fracturing with fluffy wire drawing and burning through for laser power density of 236.17W/cm2, 407.39W/cm2, 634.39W/cm2, respectively. The maximum temperature of the spot center increased with the increase of laser power, with rising and falling edges varying in a stepwise way. Under the laser irradiation with the same power density, the higher value of preloading corresponded to the less fracture time. However, when the preloading was 20% over the fracture threshold, the influence of the laser power density was significantly reduced. Similarly, when the laser power density was 634.39W/cm2, the fracture time was less influenced by the value of