该文研究了1-3-2压电复合材料的厚度振动谐振频率与尺寸的关系。应用压电学和弹性动力学理论建立了机电等效图, 对1-3-2压电复合材料的厚度振动模态进行了机电理论分析, 并对其谐振频率进行了计算。利用有限元仿真软件分析了在厚度振动模态下, 1-3-2压电复合材料谐振频率、反谐振频率与尺寸变化的关系。结果表明, 纵向尺寸比变大时, 频率曲线呈下降趋势; 横向尺寸比变大时, 频率曲线呈上升趋势; 横纵尺寸比变大时, 频率曲线呈缓慢下降趋势; 基底厚度变大时, 频率曲线呈先减小后增大趋势。4种情况中, 纵向尺寸比对于整体的谐振和反谐振频率影响最显著。

为提高柔性可穿戴传感器的电信号输出能力, 设计并制备了以聚二甲基硅氧烷(PDMS)为基体, 锆钛酸铅(PZT)为压电相的0-3型压电复合材料。探究了不同固相含量对浆料流变性能的影响。结果表明, 浆料的粘度与剪切模量随银修饰PZT质量分数(w(PZT))的增加而增加, w(PZT)=38%时浆料屈服点为398.1 Pa, 具有最优的可打印性。在电信号测试中, 经银修饰样品最大电压峰-峰可达20.54 V, 约为未经银修饰样品最大电压峰-峰值的5倍。弯曲测试中, 在长度之差ΔL=7 cm时, 样品电压峰-峰值为55 mV, 证明样品具备柔性传感性能。

1-3型压电复合材料具备优异的机电耦合性能, 这对于高性能压电换能器的开发具有重要意义。该文采用低成本的切割填充法制备了不同结构参数的1-3型PZT/环氧树脂复合材料, 并结合有限元模拟法对其压电性能、机电响应特性和温度稳定性进行了系统地研究。1-3阵列结构对平面方向应变产生了很大的衰减, 使能量更集中于厚度共振模式。复合材料的高径比是影响机电耦合性能的主要因素, 更精细的阵列结构有利于高性能压电换能器的制造。在-20~60 ℃内, 1-3型压电复合材料的厚度机电耦合系数约为0.61, 变化率小于1%,表现出良好的温度稳定性。

3-3型压电复合材料在超声波传感器、水下声学检测等领域有着广泛的应用。锆钛酸铅(PZT)陶瓷通过复合有望制备具有低介电常数、低脆性等优点的复合材料。采用直写成型技术制备了PZT三维木堆结构支架, 结合浸渍法填充环氧树脂制备了3-3型PZT/环氧树脂压电复合材料。研究了陶瓷相体积分数对3-3型PZT/环氧树脂压电复合材料的介电、压电、铁电性能的影响, 并对比了PZT陶瓷支架与PZT/环氧树脂复合材料的介电与压电性能。研究结果表明, 随着陶瓷相体积分数的增加, 复合材料的介电常数、压电常数及剩余极化强度都会增大, PZT支架具有更大的介电常数、压电常数、压电电压常数; 当陶瓷相体积分数为36%时, PZT支架与PZT/环氧树脂的压电电压常数分别达到151.0 mV·m/N与104.0 mV ·m/N。PZT/环氧树脂复合材料同时具备了压电陶瓷的硬度、电性能, 以及聚合物的柔韧性、低密度等优势, 其应用前景良好。

该文设计了一种基于1-1-3型压电复合材料的直线型换能器阵列, 并采用有限元法分析了阵元的导纳特性。应用有限元法对比分析了基于1-1-3型和1-3型压电复合材料直线型换能器阵列的电导, 以及阵元位置对电导的影响。为进一步验证仿真结果, 该文设计了一种“一体成型”的换能器阵列制备工艺, 并制备了实验样品。实验结果表明, 1-1-3型直线型换能器阵列比1-3型直线型换能器接收灵敏度一致性稳定提高4 dB, 发射电压响应的一致性稳定在0.6 dB内, 有效地提高了高频换能器阵的阵元一致性。

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.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.