Evaluation of Thermal Properties of E-Glass/ Epoxy Composites Filled By Different Filler Materials
This paper compares the values of the thermal and fire resistance properties of composites made using the hand layup technique. E-Glass fiber reinforced epoxy composites was fabricated by filling varying concentration of aluminum oxide (Al2O3), magnesium hydroxide(Mg(OH)2), silicon carbide (SiC), and hematite powder. The main aim of this work was to determine the thermal conductivity, thermal expansion coefficient, time to ignition and flame propagation rate of composites. Experimental results show that Al2O3 and Mg (OH)2 filled composites exhibited low thermal conductivities. Composites filled by SiC particles exhibited low thermal expansion coefficient when compared with other filled composites. Fire test results indicated that increase the loading of Al2O3, Mg (OH)2, and hematite powder increase the time to ignition and reduces the flame propagation rate of composites.
Post-fire mechanical properties of glass-reinforced polyester composites
An investigation into changes in the mechanical properties of glass-reinforced polyester composites after exposure to intense radiant heat is presented. The tension, compression, flexure and interlaminar shear properties fell rapidly with increasing heat flux and heat-exposure time owing, mainly, to charring and delamination cracking caused by burning of the composite. Substantially higher post-fire mechanical properties were attained when the composite was protected from the radiant heat with a thermal barrier coating that delayed the onset of combustion. Analytical models for determining the post-fire tension, compression and flexure properties are presented. The potential use of the models for making preliminary predictions of reductions to the failure loads of glass-reinforced polyester composite structures on marine craft and naval ships, such as decks and bulkheads, caused by fire is discussed.
Global attractivity in time-delayed predator-prey systems
Abstract For a predator-prey model with time-delay due to gestation, criteria are obtained for persistence and global attractivity. The global attractivity criteria apply only to models with a decreasing prey isocline.