NUMERICAL SOLUTION OF THERMAL STRESSES IN A COMPOSITE HOLLOW DISK UNDER STEEP TEMPERATURE

Resumo

This work studies the effects of thermal stresses in composite disk during heating by imposing
high heat fluxes at the inner face. The medium is formed by layers of steel, cement and rock. Thermal
stresses are caused by distinct displacements in different layers. It is important to analyze the movements
of contraction and expansion of these layers in addiction to verify the tensions caused by temperature
difference. This configuration, or say, composite layers, is found in completed oil wells. These stresses
can induce fissures and failures that can let a movement of fluids from oil reservoir through them and
cause environmental problems in oceans and seas where oil is extracted. The numerical solution is based
on finite element method (FEM) applied by the commercial code ANSYS

R which was employed in the
simulations. Materials of layers were assumed isotropic and no thermal resistance between them was
considered. Transient heat transfer was analyzed. The idea of this work is to investigate the interaction
between steel and cement because it configures a point of concern due to the fact that coefficients of
thermal expansion from these materials are different and there is a large probability of unwanted fissures.
Another point is to establish an optimal heat flux that does not allow a formation of fissures and empty
spaces between the layers that allow a flow of fluids from the oil field through them, especially at the
steel-cement interface.