多频简谐激励调制是一种无损检测方法,采用低频振动信号和高频超声波信号在裂纹损伤处的非线性调制来检测损伤。以1 k W风力机叶片为实验对象,研究了多频简谐激励调制下,叶片裂纹位置和长度对结构非线性动力学响应特性的影响规律。研究...多频简谐激励调制是一种无损检测方法,采用低频振动信号和高频超声波信号在裂纹损伤处的非线性调制来检测损伤。以1 k W风力机叶片为实验对象,研究了多频简谐激励调制下,叶片裂纹位置和长度对结构非线性动力学响应特性的影响规律。研究结果发现,含裂纹损伤的风机叶片会出现明显的非线性调制现象,且随着裂纹长度的增加、以及裂纹位置距叶根越远,非线性调制现象明显增强。实验验证了该方法用于风机叶片早期裂纹损伤检测的可行性。展开更多
Triboelectric nanogenerators(TENGs)are highly promising energy-harvesting devices that exhibit considerable potential for use in self-powered wearable electronics.Nano/microfillers and surface microstructure modificat...Triboelectric nanogenerators(TENGs)are highly promising energy-harvesting devices that exhibit considerable potential for use in self-powered wearable electronics.Nano/microfillers and surface microstructure modification have been proposed to improve the triboelectric performance of TENGs.In this work,performance-enhanced flexible polydimethylsiloxane(PDMS)was developed through bi-material(reduced graphene oxide/fluorinated ethylene propylene,rGO/FEP)modification and filtrationmembrane-patterned surface microstructure.The rGO/FEP with high charge-inducing and-trapping capabilities can be used as the dielectric-enhanced filler for improving triboelectricity.Ordered micro-dents of 5–50μm are created on the modified PDMS surface with an increased contact area of TENG.Compared with the pure PDMS,the modified PDMS film-based TENG could deliver a substantial enhancement in power density(0.87 mW cm^(-2))by 28 times.Further,the versatility of this device is demonstrated in human activity monitoring and capacitor charging.This work provided a simple,high-tunability,and scalable approach for improving the output performance of TENGs for biomechanical energy-harvesting devices that can be integrated into self-powering wearable electronics.展开更多
Vibration energy harvesting is a promising approach for sustainable energy generation from ambience to meet the development of self-powered systems.Here,we propose a novel compact non-resonant magnetically modulated r...Vibration energy harvesting is a promising approach for sustainable energy generation from ambience to meet the development of self-powered systems.Here,we propose a novel compact non-resonant magnetically modulated rotational energy harvester(MMR-EH)for low frequency and irregular vibration.Through the rational arrangement of multiple magnetic fields in space,a ring route with low potential energy is established.A movable magnet can be non-contact modulated by the magnetic force to move along the ring route under irregular vibration,which is instrumental in electromechanical energy conversion.A dynamic model of the MMR-EH is developed based on the energy method and verified experimentally.The effects of key parameters on the magnetically modulated route are analysed.The simulation and experimental results demonstrate that the MMR-EH can effectively harvest the energy from ultra-low frequency(3 Hz)and irregular vibration.At a reciprocating vibration frequency of 10 Hz and an amplitude of 20 mm,the harvester can produce an average power of 0.29 mW.展开更多
文摘多频简谐激励调制是一种无损检测方法,采用低频振动信号和高频超声波信号在裂纹损伤处的非线性调制来检测损伤。以1 k W风力机叶片为实验对象,研究了多频简谐激励调制下,叶片裂纹位置和长度对结构非线性动力学响应特性的影响规律。研究结果发现,含裂纹损伤的风机叶片会出现明显的非线性调制现象,且随着裂纹长度的增加、以及裂纹位置距叶根越远,非线性调制现象明显增强。实验验证了该方法用于风机叶片早期裂纹损伤检测的可行性。
基金the National Natural Science Foundation of China(Grant Nos.51902104 and 12172127)the Key Project of Scientific Research Project of Hunan Provincial Department of Education(Grant Nos.22A0515 and 21A0463)。
文摘Triboelectric nanogenerators(TENGs)are highly promising energy-harvesting devices that exhibit considerable potential for use in self-powered wearable electronics.Nano/microfillers and surface microstructure modification have been proposed to improve the triboelectric performance of TENGs.In this work,performance-enhanced flexible polydimethylsiloxane(PDMS)was developed through bi-material(reduced graphene oxide/fluorinated ethylene propylene,rGO/FEP)modification and filtrationmembrane-patterned surface microstructure.The rGO/FEP with high charge-inducing and-trapping capabilities can be used as the dielectric-enhanced filler for improving triboelectricity.Ordered micro-dents of 5–50μm are created on the modified PDMS surface with an increased contact area of TENG.Compared with the pure PDMS,the modified PDMS film-based TENG could deliver a substantial enhancement in power density(0.87 mW cm^(-2))by 28 times.Further,the versatility of this device is demonstrated in human activity monitoring and capacitor charging.This work provided a simple,high-tunability,and scalable approach for improving the output performance of TENGs for biomechanical energy-harvesting devices that can be integrated into self-powering wearable electronics.
基金the National Science Fund for Distinguished Young Scholars(Grant No.11625208)the National Natural Science Foundation of China(Grant No.11802091)+2 种基金the China Postdoctoral Science Foundation(Grant No.2018M640386)the Hunan Province Science and Technology Innovation Program(Grant Nos.2019RS2044,2019JJ50099and 2018RS3104)the State Key Laboratory of Mechanical System and Vibration(Grant No.MSV202005)。
文摘Vibration energy harvesting is a promising approach for sustainable energy generation from ambience to meet the development of self-powered systems.Here,we propose a novel compact non-resonant magnetically modulated rotational energy harvester(MMR-EH)for low frequency and irregular vibration.Through the rational arrangement of multiple magnetic fields in space,a ring route with low potential energy is established.A movable magnet can be non-contact modulated by the magnetic force to move along the ring route under irregular vibration,which is instrumental in electromechanical energy conversion.A dynamic model of the MMR-EH is developed based on the energy method and verified experimentally.The effects of key parameters on the magnetically modulated route are analysed.The simulation and experimental results demonstrate that the MMR-EH can effectively harvest the energy from ultra-low frequency(3 Hz)and irregular vibration.At a reciprocating vibration frequency of 10 Hz and an amplitude of 20 mm,the harvester can produce an average power of 0.29 mW.
