Analysis Of Steady Thermal Stress In A Functionally Graded Hollow Cylinder

Functionally graded materials(FGMs)are a class of new advanced composites formed of two or more constituent phases with continuously varying material properties in one or multi spatial directions.This new advanced material can provide some excellent thermo-mechanical properties,such as high strength,superb heat resistance,which the common materials do not possess.Thus,cylindrical structures consisted of functionally graded materials have been frequently used in various engineering applications,particularly in high-temperature environment.The thermal stress of functionally graded cylindrical structures is a hot topic of research in recent years.The thermoelastic problem of an infinite long functionally graded hollow cylinder subjected to both axisymmetric mechanical and thermal loads was studied in this paper.The material properties,except Poisson's ratio,were assumed to vary as linear and rational fraction functions of the radius.The heat conduction equation was solved firstly,and then the Navier equation in terms of the displacement was derived and solved.Furthermore,the effects on the radial displacement and the thermal stresses under different circumstances were discussed graphically.Assisted by numerical results and some discussions,the fruits of the study in this thesis were obtained as follows:(1)The theoretical solutions of radial displacement and thermal stresses for the functionally graded hollow cylinder of one-dimensional steady-state are obtained and validated by the results carried out by the ANSYS finite element software.(2)The ratios of the elastic modulus and the thermal expansion coefficient result remarkable influences on the radial displacement and the thermal stresses for each model.It is also seen that the ratio of the thermal conductivity does have significant influence on the radial displacement,hoop stress and axial stress for both models,but does not on the radial stress.(3)The thickness of the cylinder greatly affects the radial displacement for each model,but it has little influence on the thermal stresses.It is also observed that the temperature field plays a significant role in the radial displacement and the thermal stresses for both models.