Piezoelectric materials are capable of actuation and sensing and have been used in a wide variety of smart devices and structures.Active fiber composite and macro fiber composite are newly developed types of piezoelectric composites,and show superior properties to monolithic piezoelectric wafer due to their distinctive structures.Numerous work has focused on the performance prediction of the composites by evaluation of structural parameters and properties of the constituent materials with analytical and numerical methods.Various applications have been explored for the piezoelectric fiber composites,including vibration and noise control,health monitoring,morphing of structures and energy harvesting,in which the composites play key role and demonstrate the necessity for further development.
The porous alumina ceramics with lamellar structure were fabricated successfully by freeze casting. The viscosities of alumina slurries, pore structures, porosities and mechanical properties of the sintered ceramics were investigated by introducing both types of alcohols as water solidification modifier into the initial slurries, such as ethanol and 1-propanol. With the addition of ethanol or 1-propanol, the viscosities of slurries increased and porosities of sintered ceramics decreased. The compressive strengths of the sintered porous alumina ceramics were improved due to a good connectivity between lamellae with the addition of both types of alcohols. The lowest porosities of 68.52% and 73.72% and highest compressive strengths of 18.2 MPa and 15.0 MPa were obtained by the addition of 30% ethanol in mass fraction and 1-propanol, respectively.
The porous HA/BaTiO_(3)ceramics have the potential to exhibit superior capabilities to promote bone in-growth.However,there are few reports on in vivo studies.Here,we fabricated bio-inspired porous HA/BaTiO_(3)composites for bone repair via freeze-casting.These composites had a unique microstructure composed of the central canal and radically distributed lamellae,similar to the structure of nature cortical bone unite,the Haversian system.Polarized and non-polarized bio-inspired porous HA/BaTiO_(3)samples were implanted into the femoral condyle of the New Zealand rabbits.It was demonstrated that the polarization of the porous HA/BaTiO_(3)played a favorable part in bone regeneration.Moreover,the combination between the osteoconductivity of the microstructure and augmented osteogenic cell behavior induced by charges on surfaces of polarized porous HA/BaTiO_(3)facilitated bone penetration through the implants.The bio-inspired porous HA/BaTiO_(3)composites are demonstrated to be promising scaffolds for bone repair.
Chun-Sheng ShaoLiang-Jian ChenRui-Min TangBo ZhangJiang-Jie TangWei-Na Ma
压电纤维复合物在驱动、传感、结构健康检测等领域具有广泛应用,研究压电纤维复合物的驱动性能对于压电纤维复合物实际应用具有重要意义。通过实验研究不同驱动电压条件(峰值、频率及偏置)对压电纤维复合物悬臂梁结构顶端位移的影响,探讨悬臂梁基板材料与压电纤维复合物驱动性能的关系,基于欧拉-伯努利梁理论利用悬臂梁顶端位移计算压电纤维复合物的驱动力。结果表明:压电纤维复合物的驱动性能具有明显的迟滞性。悬臂梁顶端位移的大小与驱动电压峰的峰值呈线性关系,且其不仅与驱动电压的峰值有关,还与驱动电压的偏置、频率有关。压电纤维复合物的驱动性能随基板不同而不同,其对刚性铝板的驱动力为5.2 m N,对柔性麦拉膜的驱动力为0.2 m N。
