Investigation For Mechanical Behaviors On Functionally Graded Symmetric Hollow Structures Under The Coupling Of Multi-fields

In this thesis, the mechanical model which based on the engineering background of functionally graded materials and functionally graded piezoelectric materials under the coupling of multi-fields is established to reflect for the stresses, electric displacement, electric potential and perturbation of magnetic field intensity vector of the main physical nature of functionally graded symmetric hollow structures and it is convenient to serve for the engineering application. By means of the power-law model of functional graded function, based on the elasticity theory, the coupling theory of multi-fields and the principles of heat conduction, the motion control equation, heat conduction equation and charge equation are established for functionally graded symmetric hollow structures. Utilizing the special function, integral transforms and mathematical tools, the static and dynamic problems of functionally graded symmetric hollow structures under the coupling of multi-fields are investigated.Through investigation on the static and dynamic problems for the stresses, electric displacement, electric potential and perturbation of magnetic intensity vector of functionally graded symmetric hollow structures under the coupling of multi-fields, the affection on the physical parameters, temperature, field strength, geometric parameters of materials and different boundary conditions are discussed. Therefore, it is possible to control the response and distribution of various physical quantities by imposing appropriate thermal loads, mechanical loads and electric loads on the functionally graded symmetric hollow structures, and it is possible to evaluate the response of the electromagnetothermoelastic stress through measuring the electrical signals.According to the above research, we can provide effective theoretical basis to dynamic strength design, dynamic invalidation analysis, structural safety assessment and reliability assessment for functionally graded symmetric hollow structures under the coupled of multi-fields.