Performance Optimization And Finite Element Calculation Of Ba-based Enhanced Flexoelectricity Ceramics

1.BTS ceramics were synthesized by the solid-phase method in this paper.The study shows that the optimum sintering temperature is 1300? to 1350??The ceramic density is 78.75% when the sintering temperature is 1250?;when the sintering temperature is higher than 1400?,high temperature causes the crystal lattice deformation which XRD patterns don't behave as standard perovskite structure2.The effect of doping Al₂O₃ on the BTS13/87 ceramics was investigated.when sintering temperature was controlled at 1300?.The results indicate that Al₂O₃ behaves as a grain-refining helper and at the same time lowers the dielectric constant and loss tangent.The BTS13/87+x wt% Al₂O₃ ceramics curie temperature are above 40?,loss tangent are greater than 0.1,the maximum dielectric constants is only about 3300.3.The effect of doping Al₂O₃ on the BTS13/87 ceramics was investigated.when sintering temperature was controlled at 1300?.When doping concentration of Al₂O₃ below 2 wt%,the BTS are perovskite structure,and doping concentration of Al₂O₃ reach 5 wt%,impurity peaks can be found in XRD patterns.The grain sizes,dielectric constants,dielectric loss and remanent polarization decreased with the increase of Al₂O₃ doping concentration.At the doping level of 0.5 wt% Al₂O₃,the maximum density of BTS15/85 is 96.52% and the maximum transverse flexoelectric coefficient of BTS15/85 is 40 ?C/m.4.This paper systematically designed a flexure composite consisting of barium strontium titanate?BST?ceramic bar and the supporting material based on a parametric sweep finite element method?FEM?simulation.Under the same strain,the composite structure has the best flexoelectric when the tungsten wire cross-section is circular,support material is tungsten carbide with 450 GPa Young's modulus,the distance of the tungsten wire center were 2.1 mm and 2.5 mm,BST in the ratio of length to width is 1/150.With proper design,the optimized flexoelectricity of this structure is expected to be approximately 50 times larger than the previous flexure device which is comprised of BST bar and tungsten wire.5.The equations of flexoelectric mechanical coupling are derived.Based on Rosen type piezoelectric transformers and characteristics of flexoelectric effect induced by strain gradient or electric field gradient,four kinds of flexoelectric transformers?trapezoidal,rectangular with hole,hourglass and spiral?had been design which can induced flexoelectric effect by strain gradient or electric field gradient.The four kinds of transformers show considerable performance on flexoelectric effect.The step-up ratio of rectangular with hole type transformer is highest which can up to 3.53�104 times.