Time dependence of material properties of FRP composites in fire

Temperature dependence of physical and mechanical properties is considered in most thermal and mechanical response models for composite materials. Based on thermogravimetry analysis, differential scanning calorimetry, and dynamic mechanical analysis conducted at different heating rates, it is demonstrated that thermophysical and thermomechanical properties are not univariate functions of temperature, but also functions of time. Temperature- and time-dependent models for physical and mechanical properties at elevated and high temperatures are proposed, which show good accordance with experimental results. Based on a finite difference method, complex realistic thermal loading programs such as the ISO fire curve can be taken into account. © 2009 SAGE Publications