The effect of material degradation on the bending of laminated plates

In the present study, the effect of material degradation in hygrothermal environment on the bending of laminated composite plates is investigated. Heat and humidity are environmental factors that affect the mechanical properties of polymers and therefore, behavior of laminated composites changes. For investigating these changes, a laminated composite is modeled through the Kirchhoff hypothesis and classical plate theory for thin plates, and the bending governing equations are derived. The resulted equation is solved for a simply supported laminated plate and exact solution is obtained for numerical analysis. The environmental effects on the mechanical properties are modeled using the available experimental results in the literature. Finally, the effects of laminate dimensions, temperature, relative humidity, fiber volume fraction, void volume fraction, lay-up on the maximum deflection of laminate is investigated in details. Results show that variation of temperature and relative humidity severely reduce the mechanical properties and affect the behavior of laminated plates.