This paper concerns the homogenization problems for porous piezocomposites with infinitely thin metalized pore surfaces.To determine the effective properties,we used the effective moduli method and the finite element ...This paper concerns the homogenization problems for porous piezocomposites with infinitely thin metalized pore surfaces.To determine the effective properties,we used the effective moduli method and the finite element approaches,realized in the ANSYS package.As a simple model of the representative volume,we applied a unit cell of porous piezoceramic material in the form of a cube with one spherical pore.We modeled metallization by introducing an additional layer of material with very large permittivity coefficients along the pore boundary.Then we simulated the nonuniform polarization field around the pore.For taking this effect into account,we previously solved the electrostatic problem for a porous dielectric material with the same geometric structure.From this problem,we obtained the polarization field in the porous piezomaterial;after that,we modified the material properties of the finite elements from dielectric to piezoelectric with element coordinate systems whose corresponding axes rotated along the polarization vectors.As a result,we obtained the porous unit cell of an inhomogeneously polarized piezoceramic matrix.From the solutions of these homogenization problems,we observed that the examined porous piezoceramics composite with metalized pore boundaries has more extensive effective transverse and shear piezomoduli,and effective dielectric constants compared to the conventional porous piezoceramics.The analysis also showed that the effect of the polarization field inhomogeneity is insignificant on the ordinary porous piezoceramics;however,it is more significant on the porous piezoceramics with metalized pore surfaces.展开更多
This paper presents a numerical homogenization analysis of a porous piezoelectric composite with a partially metalized pore surface.The metal layers can be added to the pore surfaces to improve the mechanical and elec...This paper presents a numerical homogenization analysis of a porous piezoelectric composite with a partially metalized pore surface.The metal layers can be added to the pore surfaces to improve the mechanical and electromechanical properties of ordinary porous piezocomposites.Physically,constructing that composite with completely metalized pore surfaces is a challenging process,and imperfect metallization is more expected.Here,we investigate the effects of possible incomplete metallization of pore surfaces on the composite’s equivalent properties.We applied the effective moduli theory,which was developed for the piezoelectric medium based on the Hill-Mandel principle,and the finite element method to compute the effective moduli of the considered composites.Using specific algorithms and programs in the ANSYS APDL programming language,we constructed the representative unit cell element models and performed various computational experiments.Due to the presence of metal inclusion,we found that the dielectric and piezoelectric properties of the considered composites differ dramatically from the corresponding properties of the ordinary porous piezocomposites.The results of this work showed that piezocomposites with partially metallized pore surfaces can have a higher anisotropy,compared to the pure piezoceramic matrix,due to the defects in metal coatings.展开更多
基金the framework of the RFBR project 16-58-48009 IND omi and DST.
文摘This paper concerns the homogenization problems for porous piezocomposites with infinitely thin metalized pore surfaces.To determine the effective properties,we used the effective moduli method and the finite element approaches,realized in the ANSYS package.As a simple model of the representative volume,we applied a unit cell of porous piezoceramic material in the form of a cube with one spherical pore.We modeled metallization by introducing an additional layer of material with very large permittivity coefficients along the pore boundary.Then we simulated the nonuniform polarization field around the pore.For taking this effect into account,we previously solved the electrostatic problem for a porous dielectric material with the same geometric structure.From this problem,we obtained the polarization field in the porous piezomaterial;after that,we modified the material properties of the finite elements from dielectric to piezoelectric with element coordinate systems whose corresponding axes rotated along the polarization vectors.As a result,we obtained the porous unit cell of an inhomogeneously polarized piezoceramic matrix.From the solutions of these homogenization problems,we observed that the examined porous piezoceramics composite with metalized pore boundaries has more extensive effective transverse and shear piezomoduli,and effective dielectric constants compared to the conventional porous piezoceramics.The analysis also showed that the effect of the polarization field inhomogeneity is insignificant on the ordinary porous piezoceramics;however,it is more significant on the porous piezoceramics with metalized pore surfaces.
基金This research was done in the framework of the RFBR project 20-31-90102.
文摘This paper presents a numerical homogenization analysis of a porous piezoelectric composite with a partially metalized pore surface.The metal layers can be added to the pore surfaces to improve the mechanical and electromechanical properties of ordinary porous piezocomposites.Physically,constructing that composite with completely metalized pore surfaces is a challenging process,and imperfect metallization is more expected.Here,we investigate the effects of possible incomplete metallization of pore surfaces on the composite’s equivalent properties.We applied the effective moduli theory,which was developed for the piezoelectric medium based on the Hill-Mandel principle,and the finite element method to compute the effective moduli of the considered composites.Using specific algorithms and programs in the ANSYS APDL programming language,we constructed the representative unit cell element models and performed various computational experiments.Due to the presence of metal inclusion,we found that the dielectric and piezoelectric properties of the considered composites differ dramatically from the corresponding properties of the ordinary porous piezocomposites.The results of this work showed that piezocomposites with partially metallized pore surfaces can have a higher anisotropy,compared to the pure piezoceramic matrix,due to the defects in metal coatings.
