LASER EFFECTS ON THE DYNAMIC-RESPONSE OF LAMINATED COMPOSITES

Transient response of a moving composite laminate suddenly subjected to combined mechanical load and high intensity laser irradiation was investigated. The three thermal effects, which are caused by rapid laser heating and influence the structure's dynamic behavior, are material property degradation, burn-out and induced thermal loading. To determine temperature distribution and material burn-out due to the high laser energy deposition, a modified Crank-Nicholson finite difference scheme, which includes the effects of surface ablation, degradation of thermophysical properties at elevated temperatures and heat losses from radiation and convection, was employed. The predicted thermal results were then used for thermal loading calculation and, subsequently, forced vibration analysis. Both small and large deflection composite plate theories were adopted. The inclusion of temperature-dependent mechanical properties in the analysis was also of particular importance. It was shown that the escalation or reduction of vibration response of a laminated composite subjected to transverse loads by laser irradiation depends not only upon the laser intensity, but also, which plate surface is irradiated. It was also found that a higher power laser irradiation ensures neither greater escalation nor reduction of the vibration.