A MULTILAYER COMPOSITE TRIANGULAR ELEMENT FOR STEADY-STATE CONDUCTIONCONVECTION RADIATION HEAT-TRANSFER IN COMPLEX SHELLS

Our latest study presents the theoretical formulation and computer imp lementation of a three-node six degrees of freedom multilayer flat tri angular element intended for the study of the temperature fields in co mplex multilayer composite shells. Inherent in the formulation, in thi s first introductory and self-consistent systematic study, are the thr ee modes of heat transfer, namely conduction, convection and radiation , the latter introducing in our theoretical model strong nonlinear eff ects. In the present discourse, all nonlinear terms are strictly due t o radiation; the material properties are assumed independent of temper ature but this in no way restricts the generality of the basic theory. The formulation is based on a first-order thermal lamination theory w hich assumes a linear through-the-thickness temperature variation. The following features are uniquely implemented in the computer model: (1 ) Exact integration of all matrices including the highly nonlinear rad iation matrix (2) Exact integration of all derivative (Jacobian) matri ces for efficient nonlinear analysis (3) Geometrical generality achiev ed by an arbitrarily oriented inexpensive flat shell element (4) Compa tibility with structural elements (5) Computational efficiency and sim plicity A predictor-corrector scheme in the form of the Newton-Raphson method is adopted for the solution of the steady-state nonlinear prob lem. Numerical examples, ranging from simple panels to complex anisotr opic shells substantiate the theoretical formulation and show the pote ntial of the present laminated triangular element in the computer simu lation of temperature effects in complex geometries.