Defective Evolution And Mechanical Characteristic Of Dielectric Solid Under Force And Electric Field

As an important material with the function of force, heat, electricityand light, dielectric solid material has the properties of high intensity,stiffness and excellent piezoelectric characteristic, and it has been widelyapplied into the microelectronic industry. However, defects, includingvoid and inclusion, will inevitably appear in the process of dielectric solidmaterial manufacturing. Also new piezoelectric composite doped withinclusion and fibre is gradually generalized into Microelectro MechanicalSystems (MEMS), which need further study on its properties. Thus it ismeaningful to have a good research towards these questions. Based onphase filed method, this thesis studied the morphological evolution andmigration of different defect’s configuration in the piezoelectric matrixunder different loads and material properties. Then with creep theory, thispaper analyzed the creep effect and stress relaxation effect ofelectrostrictic matrix doped with oval inclusion under infinite electricfield. The results could provide theoretic foundation for designing andmanufacturing of microelectronic component.According to the Finite Element Method theory, numerical solution of stress field, displacement field, electric field and electric displacementfield of defects in piezoelectric matrix was calculated under differentloads, configuration and matrix materials in this thesis. Substituting thesesolutions into the parameter governing equation, the morphologicalevolution and migration of defect’s configuration can be simulated bycontrolling time step. Then this paper has a detailed discussion on thecreep effect and stress relaxation effect of electrostrictic matrix. Bycomparing configuration, shear ration and volume ration of inclusion andelectrostrictic matrix, this thesis illustrated the creep and stress relaxationeffect of two kinds of electrostrictic matrix. For a good understanding ofdynamic response of piezoelectric composites, we talked about the stressfiled and magnetic field response of carbon nanotubes withinhomogeneous piezoelectric coating under a sudden impact load andmagnetic field strength.