This review presents the progress and current status of the investigation on electromechanical deformation and fracture of piezo electric/ferroelectric materials. An attempt is made to summarize a few fundamental aspe...This review presents the progress and current status of the investigation on electromechanical deformation and fracture of piezo electric/ferroelectric materials. An attempt is made to summarize a few fundamental aspects, which include electromechanical constitutive relations, piezoelectric micromechanics and electric fracture and fatigue, instead of describing all technological backgrounds, basic physics, experimental findings, and theoretical developments. A number of open questions and future prospective are presented. It is hoped that this review will encourage people to join the exploration of this important and interesting field.展开更多
In this paper, a magnetomechanical coupling constitutive relation of the giant magnetostrictive material was investigated experimentally and theoretically. A grain-oriented magnetostrictive rod of iron and rare earth ...In this paper, a magnetomechanical coupling constitutive relation of the giant magnetostrictive material was investigated experimentally and theoretically. A grain-oriented magnetostrictive rod of iron and rare earth was tested under a combined magnetomechanical loading. Two types of experimental curves were obtained, i.e., the magnetostrictive curve of the extensional strain vs the magnetic field, and the curve of the magnetic polarization intensity vs the pre-stress. A new theoretical constitutive model, based on the density of domain switching, is developed. Comparison of the theoretical predictions with the experimental results indicates that this model can capture the main characteristics of the magnetoelastic coupling deformation of a giant magnetostrictive rod.展开更多
Molecular dynamics simulations are carried out to investigate the influences of various defects on mechanical properties of wurtzite GaN nanowires by adopting the empirical Stillinger-Weber potential.Different types o...Molecular dynamics simulations are carried out to investigate the influences of various defects on mechanical properties of wurtzite GaN nanowires by adopting the empirical Stillinger-Weber potential.Different types of vacancies and grain boundaries are considered and the uniaxial loading condition is implemented along the[001]direction.It is found that surface defects have less impact on Young's moduli and critical stresses of GaN nanowires compared with random defects.The grain boundary normal to the axial direction of a nanowire would not significantly affect Young's moduli of nanowires.However,the inversion domain grain boundaries with and without wrong bonds would significantly lower Young's moduli of GaN nanowires.In addition,the inversion domain grain boundary affects the critical stress of GaN nanowires more than the grain boundary with interface normal to the axial direction of the nanowire.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10025209, 10121202, and 10572069, and the Key Project of the Ministry of Education of China under Grant No 0306.
基金The project supported by the National Natural Science Foundation of China (10025209)
文摘This review presents the progress and current status of the investigation on electromechanical deformation and fracture of piezo electric/ferroelectric materials. An attempt is made to summarize a few fundamental aspects, which include electromechanical constitutive relations, piezoelectric micromechanics and electric fracture and fatigue, instead of describing all technological backgrounds, basic physics, experimental findings, and theoretical developments. A number of open questions and future prospective are presented. It is hoped that this review will encourage people to join the exploration of this important and interesting field.
文摘In this paper, a magnetomechanical coupling constitutive relation of the giant magnetostrictive material was investigated experimentally and theoretically. A grain-oriented magnetostrictive rod of iron and rare earth was tested under a combined magnetomechanical loading. Two types of experimental curves were obtained, i.e., the magnetostrictive curve of the extensional strain vs the magnetic field, and the curve of the magnetic polarization intensity vs the pre-stress. A new theoretical constitutive model, based on the density of domain switching, is developed. Comparison of the theoretical predictions with the experimental results indicates that this model can capture the main characteristics of the magnetoelastic coupling deformation of a giant magnetostrictive rod.
基金by the National Natural Science Foundation of China under Grant No 10702058the China Postdoctoral Science Foundation under Grant No 20090451100.
文摘Molecular dynamics simulations are carried out to investigate the influences of various defects on mechanical properties of wurtzite GaN nanowires by adopting the empirical Stillinger-Weber potential.Different types of vacancies and grain boundaries are considered and the uniaxial loading condition is implemented along the[001]direction.It is found that surface defects have less impact on Young's moduli and critical stresses of GaN nanowires compared with random defects.The grain boundary normal to the axial direction of a nanowire would not significantly affect Young's moduli of nanowires.However,the inversion domain grain boundaries with and without wrong bonds would significantly lower Young's moduli of GaN nanowires.In addition,the inversion domain grain boundary affects the critical stress of GaN nanowires more than the grain boundary with interface normal to the axial direction of the nanowire.
