Measurement and modelling of the thermochemical expansion of polymer composites

Numerical Study of the Thermal Response of High-Temperature Ablative Materials

“…First, the material properties are calculated according to the following sequence: (l) to calculate the length of each grid element explicitly by using Eq. (10), (2) to calculate the densities of the solid and gas phases in each element explicitly according to Eq. (4) and the ideal gas law, respectively, (3) to avoid too many iterations, the heat transfer coefficient between the two phases is only computed at the first iteration of each time step, and (4) to estimate all the material properties in each grid element and at the interface of the grid element.…”

“…The material behavior of ablative materials has been described in detail by Schmidt [I], Tant and Henderson [2], and Kenny et aI. [3].…”

“…Most ablative materials are carbon and silica fabric polymeric composites [I]. Among them, the reinforced glass-filled polymeric composites, such as H41N and MXBE-350 [2], have been frequently utilized as the thermal barrier in military and aerospace applications because of their excellent ablative performance. The main focus of this study is on the thermal behavior of this type of improved ablative materials.…”

Modelling the Thermal Response of Composites in Fire

“…Numerous studies -most notably by Kung [7], Kansa et al [8] and Fredlund [9] -have developed thermal-chemical models that consider the processes of transient heat conduction, endothermic decomposition reactions of wood, convection flow of volatile gases, and combustion of volatiles at or near the solid surface. The current state-of-the-art for modelling the fire response of composites is defined by work published between the mid-1980s and mid-1990s by research groups lead by Henderson (from the University of Rhode Island) [10][11][12][13][14][15][16], Sullivan (Marshall Space Flight Center) [17][18][19][20], Springer (Stanford University) [21][22][23], Dimitrienko (NPO Mashinostroeniya) [2,24,25] and Gibson (University of Newcastle-upon-Tyne) [26][27][28].…”

“…The composite begins to contract when the temperature rises above ~500 o C due to formation of char, and the rate of contraction increases rapidly above 1600 o C as a result of glass fibre-carbon (char) reactions. This complex relationship between expansion and temperature is observed in many types of composite materials [11][12][13]38,39]. Florio et al [15] developed a thermal-physical model to predict the expansion of composites when exposed to fire.…”