Laser experiments under combined mechanical tensile stress have been carried out to evaluate the operational vulnerability of fiberglass composite structures to a laser irradiation. It follows that the optical propagation of the laser beam inside the semi-transparent reinforced laminate is one of the key issues of this study as it rules every phenomenon occurring at a later stage. The Radiative Transfer Equation (RTE) has been used together with spectrometric measurements to assess the initial coupling of the monochromatic laser beam with the optically diffusing material. However, the partial absorption of the high-energy laser beam quickly leads to very-high temperatures on the irradiated area that can induce several phase transitions of the polymer. These changeovers and their influence on the optical and thermal properties of the system have been investigated with conventional methods (TGA and DSC) and reproduced with a time- and temperature-dependent kinetic scheme based on the Arrhenius equation. Finally, a 1D multiphysics model has been developed to reproduce the temperature evolution recorded during laser trials. Based on a time-explicit scheme, this computational approach shows a fairly good agreement and allows for a further understanding of the multiple phenomena occurring under a laser irradiation.
From their prior emergence in the military domain but also nowadays in the civilian area, unmanned air vehicles constitute a growing threat to the todays civilization. In this respect, novel laser weapons are considered to eradicate this menace and the vulnerability of typical aeronautic materials under 1.07μm-wavelength irradiations is also investigated. In this paper, Kubelka-Munk optical parameters of laminated glass fiber-reinforced plastic composites are first assessed to build up a basic analytical interaction model involving internal refraction and reflection as well as the scattering effect due to the presence of glass fibers. Moreover, a thermo-gravimetric analysis is carried out and the kinetic parameters of the decomposition reaction extracted from this test with the Friedman method are verified trough a comparison with experimental measurements.