Three-dimensional Contact Of Transversely Isotropic Coated Structure And Piezoelectric Ceramic Coating Device

Coated structures are widely used in engineering for improving the reliability and durability of structures.The main reason for the failure of this type of structure is the stress concentration in the coating,substrate,and their interface,which is caused by various contact loads.Piezoelectric ceramic coated devices are widely used as important functional devices including the sensors,actuators and energy-harvester.The fine calculation of the mechanical-electric field of the coated structure and piezoelectric ceramic coated devices under the force and electrical contact loads is a necessary condition for their safety and functional analysis and design.Under this engineering requirement,The three-dimensional mechanical-electrical fields of the transversely isotropic coated structures and piezoelectric ceramic coated devices under the most common spherical,conical,and cylindrical contact load are studied in this dissertation,and a series of exact solutions are presented.The main work includes the following three aspects.(1)For transversely isotropic coated structure,based on the general solution of the three-dimensional governing equation of mechanical field for transversely isotropic materials,the three-dimensional exact solutions of mechanical full-field in the coating and substrate under three kinds of mechanical contact loads including spherical,conical,and cylindrical contact load are derived in two cases of smooth and frictional contact.Based on the exact solutions,the contact radius is calculated,the coating thickness is optimized,the delamination area is discussed,and the coating material is optimized.Based on this work,the safety analysis and design of coated structure are carried out.(2)For piezoelectric ceramic coated devices,based on the general solution of the three-dimensional governing equation of coupled electro-mechanical field in piezoelectric ceramic materials and the general solution of the three-dimensional governing equation of uncoupled electro-mechanical field in the transversely isotropic materials,the three-dimensional electro-mechanical full-field exact solutions of the piezoelectric ceramic coating and substrate under three kinds of electro-mechanical contact loads incuding spherical,conical,and cylindrical electro-mechanical contact loads are derived respectively.Based on the presented exact solution,the safety and function analysis and design of piezoelectric ceramic coated devices are carried out.(3)Based on above research results and mathematical platform,a special software platform for contact mechanics of coated structures is presented.Because the calculation method is not the traditional numerical calculation method(such as the finite element method),and the three-dimensional full-field exact solutions are given directly by explicit functions,the software platform has high calculation precision and efficiency.There is no need for special calculation skills in the process of using this software platform.It is convenient for the engineers to find the relationship between each influencing factor quickly and accurately.And then one can easily grasp the main question and finally get the coated structure with low cost and superior performance.