In recent years, it is necessary to monitor every civil and mechanical structure for the safety of human life and property. By using PZT, monitoring of structures is possible with some limitations such as direct attac...In recent years, it is necessary to monitor every civil and mechanical structure for the safety of human life and property. By using PZT, monitoring of structures is possible with some limitations such as direct attachment to the host structure, structure subjected to impact from external forces, inaccessible structure, high temperature locations, and structures with complex geometry and curved surfaces. To overcome these limitations, a new technique is employed for structural health monitoring. Using the advanced technique, transducer is prepared by attaching PZT with metal connectors which is in turn attached to the monitored structure. This paper demonstrates experimental study on mild steel pipes. Different aspects of SHM are studied. The proposed technique effectively detects locations of damages and severity of damages of pipe specimen. The technique is also employed to study effect of temperature variation along with detecting progressive damage of pipe specimen when it is subjected to steady constant high temperature. This technique is applicable to high temperature locations as the temperature of PZT maintained below its Curie temperature by introducing metal connector between structure and PZT patch. For the quantification of damages, the RMSD index formula is used.展开更多
Piezoelectric microelectromechanical systems(MEMS)mirrors enable precise and rapid beam steering with low power consumption,making them essential components in light detection and ranging(LiDAR)and advanced optical im...Piezoelectric microelectromechanical systems(MEMS)mirrors enable precise and rapid beam steering with low power consumption,making them essential components in light detection and ranging(LiDAR)and advanced optical imaging systems.Lead zirconate titanate(PZT)offers a high piezoelectric coefficient suitable for such applications.However,its elevated processing temperatures(typically 500°C–700°C),lead content that raises contamination concerns during complementary metal-oxide-semiconductor(CMOS)integration,and hysteresis-induced nonlinearity limit its broader integration into MEMS mirrors.In contrast,aluminum nitride(AlN),with low deposition temperatures(below 400°C)and contamination-free composition,offers CMOS compatibility,environmental stability,and low hysteresis,making it a promising lead-free alternative.However,its intrinsically low piezoelectric coefficient limits actuation efficiency for large scan angles.To overcome this limitation,scandium(Sc)doping has emerged as an effective strategy to enhance the piezoelectric response of AlN.Sc-doped AlN(AlScN)enables relatively large scan angles in MEMS mirror applications due to its significantly enhanced piezoelectric coefficients and reduced mechanical stiffness,while retaining essential advantages,such as CMOS compatibility and environmental robustness.This review comprehensively examines the recent progress in AlN and AlScN for MEMS mirror applications.We focus on its impact on piezoelectric properties,fabrication techniques,and mirror performance.Furthermore,we provide a comparative assessment of AlN-and AlScN-based MEMS mirrors,highlighting their respective advantages,limitations,and application potentials.Finally,this review summarizes recent developments and research trends,providing insights into their performance benefits and directions for future research.展开更多
文摘In recent years, it is necessary to monitor every civil and mechanical structure for the safety of human life and property. By using PZT, monitoring of structures is possible with some limitations such as direct attachment to the host structure, structure subjected to impact from external forces, inaccessible structure, high temperature locations, and structures with complex geometry and curved surfaces. To overcome these limitations, a new technique is employed for structural health monitoring. Using the advanced technique, transducer is prepared by attaching PZT with metal connectors which is in turn attached to the monitored structure. This paper demonstrates experimental study on mild steel pipes. Different aspects of SHM are studied. The proposed technique effectively detects locations of damages and severity of damages of pipe specimen. The technique is also employed to study effect of temperature variation along with detecting progressive damage of pipe specimen when it is subjected to steady constant high temperature. This technique is applicable to high temperature locations as the temperature of PZT maintained below its Curie temperature by introducing metal connector between structure and PZT patch. For the quantification of damages, the RMSD index formula is used.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(Nos.RS-2023-00222166 and RS-2024-00457040).
文摘Piezoelectric microelectromechanical systems(MEMS)mirrors enable precise and rapid beam steering with low power consumption,making them essential components in light detection and ranging(LiDAR)and advanced optical imaging systems.Lead zirconate titanate(PZT)offers a high piezoelectric coefficient suitable for such applications.However,its elevated processing temperatures(typically 500°C–700°C),lead content that raises contamination concerns during complementary metal-oxide-semiconductor(CMOS)integration,and hysteresis-induced nonlinearity limit its broader integration into MEMS mirrors.In contrast,aluminum nitride(AlN),with low deposition temperatures(below 400°C)and contamination-free composition,offers CMOS compatibility,environmental stability,and low hysteresis,making it a promising lead-free alternative.However,its intrinsically low piezoelectric coefficient limits actuation efficiency for large scan angles.To overcome this limitation,scandium(Sc)doping has emerged as an effective strategy to enhance the piezoelectric response of AlN.Sc-doped AlN(AlScN)enables relatively large scan angles in MEMS mirror applications due to its significantly enhanced piezoelectric coefficients and reduced mechanical stiffness,while retaining essential advantages,such as CMOS compatibility and environmental robustness.This review comprehensively examines the recent progress in AlN and AlScN for MEMS mirror applications.We focus on its impact on piezoelectric properties,fabrication techniques,and mirror performance.Furthermore,we provide a comparative assessment of AlN-and AlScN-based MEMS mirrors,highlighting their respective advantages,limitations,and application potentials.Finally,this review summarizes recent developments and research trends,providing insights into their performance benefits and directions for future research.
