A nonlinear finite element model is provided for the thermal post buckling and linear flutter behavior of composite panels. Panel subjects to combined aerodynamic and thermal loads. The governing equations are derived using the classical plate theory and the principle of virtual work. The effect of large deflection is included in the formulation through the von Kármán nonlinear strain-displacement relations. To account for the temperature dependence on material properties, the thermal strain is stated as an integral quantity of the thermal expansion coefficient with respect to temperature. The aerodynamic pressure is modeled using the quasi-steady first order piston theory. The Newton-Raphson iteration method is employed to obtain the nonlinear aero-thermal post-buckling deflections, and a frequency-domain solution is presented to predict the critical dynamic pressure at different elevated temperatures. Finally, numerical results are provided to depict the optimum lamination scheme in order to maximize the aero-thermal stability of such panels. The optimum solution is obtained by Genetic Algorithms.

Thermal properties of chopped composites are important parameters for determining application and use of this category of materials. An experimental identification for thermal properties of different composite materials was conducted. In order to investigate the effect of fiber, three different chopped fibers with a phenol resin as a matrix; Carbon fiber, Basalt, and Fiberglass, were selected to determine their thermal properties. Also, the matrix is changed for carbon fiber; phenol resin and epoxy resin, to show the influence of matrix material. Two important parameters were investigated which are the thermal conductivity (TC) and the thermal expansion coefficient (CTE). For the four materials, the thermal conductivity obtained is very low with a range of K = 0.159 w/m °c for the Carbon / Phenol to K = 0.1942 w/m °c for the Carbon / Epoxy, so those materials are used as thermal insulators. On the other side, thermal expansion coefficient has also very low negative values for the Phenol based composites with a range of -146.6 µm/m°c for fiber glass / phenol to -273.7 µm/m°c for carbon fiber / phenol, and for the Epoxy based composites the CTE has a low positive value which is 1049 µm/m°c for carbon fiber / epoxy .

This work deals with the characterization of chopped fiber glass composite. The resin matrix was a phenol base. Sheets of this composite have been cured and cut to make sample specimens for testing. Four mechanical testing have been conducted for these material including tensile test at different temperatures, bending test, compression test and hardness test. Three thermal tests including thermal conductivity determination, thermal expansion coefficient determination and ablation test have been conducted. The results show that this material has very good thermal properties capable of resisting high temperatures.A nozzle for rocket motor has been made from this material as insulators, and static firing test has been conducted and the temperatures inside this composite material have been measured. Investigation of the thermal loads response of composite nozzle has been done using FE using ANSYS package software and the calculated temperatures have been recorded from the same places that chosen in the real firing test. By comparing the measured and obtained temperature for the fiber glass, there is a great agreement between them. The selected composite material resists the high temperatures so this used as thermal protective material.