The behavior of two parallel symmetric cracks in piezoelectric materials under anti-plane shear loading was studied by the Schmidt method for the permeable crack face conditions. By using the Fourier transform, the pr...The behavior of two parallel symmetric cracks in piezoelectric materials under anti-plane shear loading was studied by the Schmidt method for the permeable crack face conditions. By using the Fourier transform, the problem can be solved with two pairs of dual integral equations in which the unknown variable is the jump of the diplacement across the crack surfaces. These equations were solved using the Schmidt method. The results show that the stress and the electric displacement intensity factors of cracks depend on the geometry of the crack. Contrary to the impermeable crack surface condition solution, it is found that the electric displacement intensity factors for the permeable crack surface conditions are much smaller than the results for the impermeable crack surface conditions.展开更多
Using a method of potential functions introduced successively to integrate the field equations of three-dimensional problems for transversely isotropic piezoelectric materials, we obtain the so-called general solution...Using a method of potential functions introduced successively to integrate the field equations of three-dimensional problems for transversely isotropic piezoelectric materials, we obtain the so-called general solution in which the dis- placement components and electric potential functions are represented by a singular function satisfying some special partial differential equations of 6th order. In order to analyse the mechanical-electric coupling behaviour of penny-shaped crack for above materials, another form of the general solution is obtained under cylindrical coordi- nate system by introducing three quasi-harmonic functions into the general equations obtained above. It is shown that both the two forms of the general solutions are complete. Furthermore, the mechanical-electric coupling behaviour of penny-shaped crack in transversely isotropic piezoelectric media is analysed under axisymmetric tensile loading case, and the crack-tip stress field and electric displacement field are obtained. The results show that the stress and the electric displacement components near the crack tip have (r^(-1/2)) singularity.展开更多
Within the framework of nonlinear eleetroelasticity, the stress field near to the crack tip in an infinite piezoelectric media subject to a far field uniform loading is studied by using an electrical strip saturation ...Within the framework of nonlinear eleetroelasticity, the stress field near to the crack tip in an infinite piezoelectric media subject to a far field uniform loading is studied by using an electrical strip saturation model and the complex variable method. And the emphasis is placed on the stress field near to the crack tip. The obtained solutions show that the normalized stress components at an arbitrary point near to the crack tip are determined by the angle of the point. Moreover, the stress components are independent of the distance from the point to the ori- gin of the coordinate. The distributions of in-plane stress components near to the crack tip are analyzed based on numerical results for PZT-SH. Compared with some related solutions, results show that the solutions are valid.展开更多
By using the well-developed integral transform methodology, the dynamic response of stress and electric displacement around a finite crack in an infinite piezoelectric strip are investigated under arbitrary dynamic an...By using the well-developed integral transform methodology, the dynamic response of stress and electric displacement around a finite crack in an infinite piezoelectric strip are investigated under arbitrary dynamic anti-plane loads. The dynamic stress intensity factors and electric displacement are obtained analytically. It is shown that the dynamic crack-tip stress and electric field still have a square-root singularity. Numerical computations for the dynamic stress intensity factor show that the electric load has a significant influence on the dynamic response of stress field. The higher the ratio of the crack length to the width of the strip, the higher the peak value of the dynamic stress intensity factor is. On the other hand, the dynamic response of the electric field is determined solely by the applied electric load. The electric field will promote or retard the propagation of the crack depending on the time elapse since the application of the external electro-mechanical loads. (Author abstract) 9 Refs.展开更多
Composite-type piezoelectric nanogenerator(PENG)can potentially provide power to the flexible electronics devices by harvesting the mechanical energy.The electricity output of the PENG is not entirely excavated until ...Composite-type piezoelectric nanogenerator(PENG)can potentially provide power to the flexible electronics devices by harvesting the mechanical energy.The electricity output of the PENG is not entirely excavated until now because the polarization dipoles are not sufficiently aligned during the high-voltage poling process.In this study,some Ag particles are attached on the(K_(0.4425)Na_(0.52)Li_(0.0375))(Nb_(0.86)Ta_(0.06)Sb_(0.08))O_(3)(KNN)piezoelectric particles and then they are mixed with multi-walled carbon nanotubes and polydimethylsiloxane to fabricate the PENG device.The Ag particles can reduce the optimal poling electric field from 10 kV/mm down to 5 kV/mm.The PENG device with Ag particles poled at 5 kV/mm can generate the highest open-circuit voltage of 282 V,short-circuit voltage of 32.2 mA,and maximum instantaneous power of 3.5mW under the external mechanical stress of 10 kPa without timedependent degradation(only 27.9 V and 2.6 mA for the pure KNN-based PENG poled at 10 kV/mm).These are much better than previously reported composite-type PENG.The electrical energy generated from the PENG(20mm×40 mm)can light up 40 white light emitting diodes instantaneously without any storage unit during the stomping stage.展开更多
文摘The behavior of two parallel symmetric cracks in piezoelectric materials under anti-plane shear loading was studied by the Schmidt method for the permeable crack face conditions. By using the Fourier transform, the problem can be solved with two pairs of dual integral equations in which the unknown variable is the jump of the diplacement across the crack surfaces. These equations were solved using the Schmidt method. The results show that the stress and the electric displacement intensity factors of cracks depend on the geometry of the crack. Contrary to the impermeable crack surface condition solution, it is found that the electric displacement intensity factors for the permeable crack surface conditions are much smaller than the results for the impermeable crack surface conditions.
基金The project supported by the Natural Science Foundation of Shaanxi Province, China
文摘Using a method of potential functions introduced successively to integrate the field equations of three-dimensional problems for transversely isotropic piezoelectric materials, we obtain the so-called general solution in which the dis- placement components and electric potential functions are represented by a singular function satisfying some special partial differential equations of 6th order. In order to analyse the mechanical-electric coupling behaviour of penny-shaped crack for above materials, another form of the general solution is obtained under cylindrical coordi- nate system by introducing three quasi-harmonic functions into the general equations obtained above. It is shown that both the two forms of the general solutions are complete. Furthermore, the mechanical-electric coupling behaviour of penny-shaped crack in transversely isotropic piezoelectric media is analysed under axisymmetric tensile loading case, and the crack-tip stress field and electric displacement field are obtained. The results show that the stress and the electric displacement components near the crack tip have (r^(-1/2)) singularity.
基金the Innovation Project for Graduates in Jiangsu Province~~
文摘Within the framework of nonlinear eleetroelasticity, the stress field near to the crack tip in an infinite piezoelectric media subject to a far field uniform loading is studied by using an electrical strip saturation model and the complex variable method. And the emphasis is placed on the stress field near to the crack tip. The obtained solutions show that the normalized stress components at an arbitrary point near to the crack tip are determined by the angle of the point. Moreover, the stress components are independent of the distance from the point to the ori- gin of the coordinate. The distributions of in-plane stress components near to the crack tip are analyzed based on numerical results for PZT-SH. Compared with some related solutions, results show that the solutions are valid.
基金The project supported by the National Natural Science Foundation of Chinathe Post-Doctor Science Foundation of China
文摘By using the well-developed integral transform methodology, the dynamic response of stress and electric displacement around a finite crack in an infinite piezoelectric strip are investigated under arbitrary dynamic anti-plane loads. The dynamic stress intensity factors and electric displacement are obtained analytically. It is shown that the dynamic crack-tip stress and electric field still have a square-root singularity. Numerical computations for the dynamic stress intensity factor show that the electric load has a significant influence on the dynamic response of stress field. The higher the ratio of the crack length to the width of the strip, the higher the peak value of the dynamic stress intensity factor is. On the other hand, the dynamic response of the electric field is determined solely by the applied electric load. The electric field will promote or retard the propagation of the crack depending on the time elapse since the application of the external electro-mechanical loads. (Author abstract) 9 Refs.
基金supported by the China Postdoctoral Science Foundation(Grant No.2017M612177)National Natural Science Foundation of China(Grant Nos.51702119,51702122)Postdoctoral Science Foundation from University of Jinan.
文摘Composite-type piezoelectric nanogenerator(PENG)can potentially provide power to the flexible electronics devices by harvesting the mechanical energy.The electricity output of the PENG is not entirely excavated until now because the polarization dipoles are not sufficiently aligned during the high-voltage poling process.In this study,some Ag particles are attached on the(K_(0.4425)Na_(0.52)Li_(0.0375))(Nb_(0.86)Ta_(0.06)Sb_(0.08))O_(3)(KNN)piezoelectric particles and then they are mixed with multi-walled carbon nanotubes and polydimethylsiloxane to fabricate the PENG device.The Ag particles can reduce the optimal poling electric field from 10 kV/mm down to 5 kV/mm.The PENG device with Ag particles poled at 5 kV/mm can generate the highest open-circuit voltage of 282 V,short-circuit voltage of 32.2 mA,and maximum instantaneous power of 3.5mW under the external mechanical stress of 10 kPa without timedependent degradation(only 27.9 V and 2.6 mA for the pure KNN-based PENG poled at 10 kV/mm).These are much better than previously reported composite-type PENG.The electrical energy generated from the PENG(20mm×40 mm)can light up 40 white light emitting diodes instantaneously without any storage unit during the stomping stage.
