Pub Date : 2024-07-21DOI: 10.1088/1361-665x/ad622a
Gang-Min Kim, Sung-Jun Lee and Chang-Lae Kim
In this study, 3D-printed Polylactic acid (PLA) specimens were manufactured and polished using various lubricants to assess their surface, friction, and wear characteristics. After polishing, the surface roughness decreased by approximately 80% compared with that before polishing, except when acetone was used as the lubricant. In particular, under deionized (DI) water and acetone lubrication conditions, the friction coefficient decreased by 63% and 70%, respectively, whereas the specific wear rate decreased by 88% and 83%, respectively, compared with the unpolished specimens. In the case of dry polishing, adhesion, friction, and wear increase owing to surface damage. Ethanol and IPA polishing resulted in hydrolysis and increased friction, but slightly decreased wear rates. The surface of the specimen polished with acetone dissolved and became very rough. Only the surface polished with DI water exhibited hydrophobic properties. When acetone and DI water were used as lubricants, the surface adhesion force, adhesion energy, friction coefficient, and wear rate were lowest. The finite element analysis results showed that the polished surface exhibited stable contact pressure and friction force, while the unpolished surface showed large fluctuations in contact pressure and friction force owing to the laminated pattern. These results suggest that the polishing process is crucial for improving the surface characteristics and mechanical performance of 3D-printed PLA parts.
本研究制作了 3D 打印聚乳酸（PLA）试样，并使用各种润滑剂对其进行抛光，以评估其表面、摩擦和磨损特性。除使用丙酮作为润滑剂外，抛光后的表面粗糙度比抛光前降低了约 80%。特别是在去离子水和丙酮润滑条件下，与未抛光试样相比，摩擦系数分别降低了 63% 和 70%，而比磨损率则分别降低了 88% 和 83%。在干抛光的情况下，由于表面损伤，附着力、摩擦力和磨损都会增加。乙醇和IPA抛光导致水解和摩擦增加，但磨损率略有下降。用丙酮抛光的试样表面溶解并变得非常粗糙。只有用去离子水抛光的试样表面具有疏水特性。使用丙酮和去离子水作为润滑剂时，表面附着力、附着能、摩擦系数和磨损率最低。有限元分析结果表明，抛光表面表现出稳定的接触压力和摩擦力，而未抛光表面则由于层叠模式而表现出较大的接触压力和摩擦力波动。这些结果表明，抛光工艺对于改善 3D 打印聚乳酸部件的表面特性和机械性能至关重要。
{"title":"Effects of liquid lubricants on the surface characteristics of 3D-printed polylactic acid","authors":"Gang-Min Kim, Sung-Jun Lee and Chang-Lae Kim","doi":"10.1088/1361-665x/ad622a","DOIUrl":"https://doi.org/10.1088/1361-665x/ad622a","url":null,"abstract":"In this study, 3D-printed Polylactic acid (PLA) specimens were manufactured and polished using various lubricants to assess their surface, friction, and wear characteristics. After polishing, the surface roughness decreased by approximately 80% compared with that before polishing, except when acetone was used as the lubricant. In particular, under deionized (DI) water and acetone lubrication conditions, the friction coefficient decreased by 63% and 70%, respectively, whereas the specific wear rate decreased by 88% and 83%, respectively, compared with the unpolished specimens. In the case of dry polishing, adhesion, friction, and wear increase owing to surface damage. Ethanol and IPA polishing resulted in hydrolysis and increased friction, but slightly decreased wear rates. The surface of the specimen polished with acetone dissolved and became very rough. Only the surface polished with DI water exhibited hydrophobic properties. When acetone and DI water were used as lubricants, the surface adhesion force, adhesion energy, friction coefficient, and wear rate were lowest. The finite element analysis results showed that the polished surface exhibited stable contact pressure and friction force, while the unpolished surface showed large fluctuations in contact pressure and friction force owing to the laminated pattern. These results suggest that the polishing process is crucial for improving the surface characteristics and mechanical performance of 3D-printed PLA parts.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"220 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141743296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-21DOI: 10.1088/1361-665x/ad5f6b
Jian Zhong, Yiwei Shu, Hao Wang and Chenxi Xing
The shape memory alloy (SMA) restrainer serves as an effective but expensive bridge restraining device. However, the impact of pulse effect on SMA design approach under pulse-like ground motions (PLGM) has not been fully quantified in previous studies, which hinders its application in near-fault regions. Therefore, based on the risk probability assessment method throughout the entire life cycle, by accounting for the comprehensive repair cost of each component damage, this paper introduces a parameter design method for SMA restrainer of near-fault bridges that considers structural parameters, pulse parameters, and economic indicators. Firstly, the repair cost ratio (RCR) of bridge system, which means the expenses for repairs expressed as a proportion of bridge replacement costs, was regarded as the life-time optimization goal and overall performance indicator. Secondly, by accounting for near-fault effects, the relationship between RCR and SMA design parameters was established by convolution algorithm of probabilistic seismic hazard analysis, demand analysis and capacity analysis. A novel probabilistic seismic demand model was utilized to quickly determine the RCR of the bridge system under PLGM. Finally, the influence of pulse period on the rational design parameter of SMA restrainer was comprehensively investigated by RCR-based method. A seismic isolation arch bridge was selected as the illustrated case in this article. The results indicate that the rational design parameters of SMA exhibit a pattern of initially rising, then falling as the pulse period increases, reaching the peak value when the pulse period approaches bridge fundamental period. Moreover, the price parameter of SMA significantly affect the optimal design parameters, and the effective range is also recommended.
形状记忆合金（SMA）约束装置是一种有效但昂贵的桥梁约束装置。然而，以往的研究并未充分量化脉冲效应在脉冲样地震动（PLGM）下对 SMA 设计方法的影响，这阻碍了其在近断层区域的应用。因此，本文基于全寿命周期风险概率评估方法，通过考虑各构件损伤的综合修复成本，提出了一种综合考虑结构参数、脉冲参数和经济指标的近断层桥梁 SMA 约束装置参数设计方法。首先，将桥梁系统的维修成本率（RCR），即维修费用占桥梁重置成本的比例，作为寿命优化目标和综合性能指标。其次，考虑近断层效应，通过概率震害分析、需求分析和容量分析的卷积算法，建立了 RCR 与 SMA 设计参数之间的关系。利用新型概率地震需求模型快速确定了 PLGM 条件下桥梁系统的 RCR。最后，利用基于 RCR 的方法全面研究了脉冲周期对 SMA 约束合理设计参数的影响。本文选择了一座隔震拱桥作为示例。结果表明，随着脉冲周期的增加，SMA 的合理设计参数呈现出先上升后下降的规律，当脉冲周期接近桥梁基本周期时达到峰值。此外，SMA 的价格参数对最佳设计参数有显著影响，同时还推荐了有效范围。
{"title":"Quantifying the effect of pulse-like ground motions on the seismic design of SMA restrained isolation bridges using probabilistic repair cost method","authors":"Jian Zhong, Yiwei Shu, Hao Wang and Chenxi Xing","doi":"10.1088/1361-665x/ad5f6b","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5f6b","url":null,"abstract":"The shape memory alloy (SMA) restrainer serves as an effective but expensive bridge restraining device. However, the impact of pulse effect on SMA design approach under pulse-like ground motions (PLGM) has not been fully quantified in previous studies, which hinders its application in near-fault regions. Therefore, based on the risk probability assessment method throughout the entire life cycle, by accounting for the comprehensive repair cost of each component damage, this paper introduces a parameter design method for SMA restrainer of near-fault bridges that considers structural parameters, pulse parameters, and economic indicators. Firstly, the repair cost ratio (RCR) of bridge system, which means the expenses for repairs expressed as a proportion of bridge replacement costs, was regarded as the life-time optimization goal and overall performance indicator. Secondly, by accounting for near-fault effects, the relationship between RCR and SMA design parameters was established by convolution algorithm of probabilistic seismic hazard analysis, demand analysis and capacity analysis. A novel probabilistic seismic demand model was utilized to quickly determine the RCR of the bridge system under PLGM. Finally, the influence of pulse period on the rational design parameter of SMA restrainer was comprehensively investigated by RCR-based method. A seismic isolation arch bridge was selected as the illustrated case in this article. The results indicate that the rational design parameters of SMA exhibit a pattern of initially rising, then falling as the pulse period increases, reaching the peak value when the pulse period approaches bridge fundamental period. Moreover, the price parameter of SMA significantly affect the optimal design parameters, and the effective range is also recommended.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"339 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141743274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-17DOI: 10.1088/1361-665x/ad5d32
Shiyu Zhao, Rongchang Hu, Guanghui Han, Huaxia Deng, Mengchao Ma, Xiang Zhong and Xinglong Gong
A rotary self-sensing magnetorheological (MR) damper(RSMRD) based on a triboelectric nanogenerator is proposed in this study, which can provide variable torque and state self-sensing without a power supply. Compared with traditional self-sensing devices, the sensing part of RSMRD has the advantages of small size, no external power supply, and good low-frequency response. The feasibility of the angular velocity self-sensing (AVS) function is verified through theoretical derivation and experimental verification. The experimental results demonstrate a linear relationship between the output voltage generated by the AVS component and the rotational speed of the rotating shaft. Additionally, the torque characteristics of the rotary self-sensing MR damper are tested, revealing a torque generation of approximately 9.26 N m at a current of 1.6 A. Furthermore, a fuzzy control algorithm for vehicle braking is proposed, based on the model parameters of RSMRD. The simulink software is used to establish a dynamic model of 1/4 car braking, with an initial braking speed of 15 m s−1. The results indicate that the vehicle comes to a complete stop after 1.64 s, with a braking distance of 10.93 m. Throughout the braking process, the vehicle slip rate remains close to the optimal slip rate of 0.2.
本研究提出了一种基于三电纳米发电机的旋转自感应磁流变（MR）阻尼器（RSMRD），该阻尼器无需电源即可提供可变扭矩和状态自感应。与传统的自感应装置相比，RSMRD 的传感部分具有体积小、无需外部电源、低频响应好等优点。通过理论推导和实验验证了角速度自感应（AVS）功能的可行性。实验结果表明，AVS 元件产生的输出电压与旋转轴的转速之间存在线性关系。此外，还测试了旋转自感应磁共振阻尼器的扭矩特性，结果显示在电流为 1.6 A 时可产生约 9.26 N m 的扭矩。此外，还根据 RSMRD 的模型参数，提出了一种用于车辆制动的模糊控制算法。使用 simulink 软件建立了 1/4 汽车制动的动态模型，初始制动速度为 15 m s-1。结果表明，车辆在 1.64 秒后完全停止，制动距离为 10.93 米。在整个制动过程中，车辆的滑移率始终接近 0.2 的最佳滑移率。
{"title":"A rotary self-sensing magnetorheological damper based on triboelectric nanogenerator","authors":"Shiyu Zhao, Rongchang Hu, Guanghui Han, Huaxia Deng, Mengchao Ma, Xiang Zhong and Xinglong Gong","doi":"10.1088/1361-665x/ad5d32","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5d32","url":null,"abstract":"A rotary self-sensing magnetorheological (MR) damper(RSMRD) based on a triboelectric nanogenerator is proposed in this study, which can provide variable torque and state self-sensing without a power supply. Compared with traditional self-sensing devices, the sensing part of RSMRD has the advantages of small size, no external power supply, and good low-frequency response. The feasibility of the angular velocity self-sensing (AVS) function is verified through theoretical derivation and experimental verification. The experimental results demonstrate a linear relationship between the output voltage generated by the AVS component and the rotational speed of the rotating shaft. Additionally, the torque characteristics of the rotary self-sensing MR damper are tested, revealing a torque generation of approximately 9.26 N m at a current of 1.6 A. Furthermore, a fuzzy control algorithm for vehicle braking is proposed, based on the model parameters of RSMRD. The simulink software is used to establish a dynamic model of 1/4 car braking, with an initial braking speed of 15 m s−1. The results indicate that the vehicle comes to a complete stop after 1.64 s, with a braking distance of 10.93 m. Throughout the braking process, the vehicle slip rate remains close to the optimal slip rate of 0.2.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"14 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141743275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-10DOI: 10.1088/1361-665x/ad5bce
Zhiqiang Fu, Yiping Shen, Songlai Wang and Jian Li
The piezoelectric fibers of Macro Fiber Composite (MFC) have a rectangular cross-section with an aspect ratio of 2. This heterogeneity poses challenges for micromechanical modeling to predict the effective mechanical properties. The High-Fidelity Generalized Method of Cells (HFGMCs) is commonly used to calculate the properties of composite materials. In this paper, a Modified High-Fidelity Generalized Method of Cells (MHFGMC) is proposed to analyze MFC properties, in which the interaction between subcells is considered by defining the quadratic directional coupling term and the shear connection matrix. The accuracy of the proposed MHFGMC model is verified by using the finite element method and experimental tests. The results show that the MHFGMC can accurately predict the effective mechanical properties of MFC, and the relative error of tensile properties compared to experimental results is within 2.29%. The MHFGMC significantly improve the accuracy of the HFGMC, the relative error of its shear modulus is decreased from 105.13% to 0.71%.
{"title":"Analytical and numerical evaluation of the effective properties of macro fiber composite (MFC)","authors":"Zhiqiang Fu, Yiping Shen, Songlai Wang and Jian Li","doi":"10.1088/1361-665x/ad5bce","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5bce","url":null,"abstract":"The piezoelectric fibers of Macro Fiber Composite (MFC) have a rectangular cross-section with an aspect ratio of 2. This heterogeneity poses challenges for micromechanical modeling to predict the effective mechanical properties. The High-Fidelity Generalized Method of Cells (HFGMCs) is commonly used to calculate the properties of composite materials. In this paper, a Modified High-Fidelity Generalized Method of Cells (MHFGMC) is proposed to analyze MFC properties, in which the interaction between subcells is considered by defining the quadratic directional coupling term and the shear connection matrix. The accuracy of the proposed MHFGMC model is verified by using the finite element method and experimental tests. The results show that the MHFGMC can accurately predict the effective mechanical properties of MFC, and the relative error of tensile properties compared to experimental results is within 2.29%. The MHFGMC significantly improve the accuracy of the HFGMC, the relative error of its shear modulus is decreased from 105.13% to 0.71%.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"17 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141586363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-10DOI: 10.1088/1361-665x/ad5bcc
Ramin Hamzehei, Mahdi Bodaghi and Nan Wu
This review serves as a comprehensive design strategy for designing quasi-zero stiffness (QZS) mechanical metamaterials (MMs). It discusses their underlying deformation mechanisms that enable the attainment of QZS behavior under both compressive and tensile loadings. While the QZS characteristic of metamaterials has garnered considerable attention, further research is essential to unlock their potential fully. Numerous QZS metamaterials have been meticulously reviewed. They comprise various elements and mechanisms, including positive and negative stiffness elements (PS and NS), PS elements with variable stiffness, bending mechanisms employing stiff joints/areas, buckling, buckling-rotating, and bending/buckling deformation mechanisms leading to a QZS feature. Furthermore, the capability of multi-material, adaptive, smart metamaterials, origami (bending around the hinge of the folded joints), and kirigami lattices (out-of-plane buckling via cutting patterns) are weighted. These diverse mechanisms contribute to achieving QZS behavior in metamaterials under both compression and tension loads, which is paramount for various mechanical applications such as passive vibration isolation. This review effectively categorizes QZS metamaterials based on their underlying mechanisms, providing scholars with valuable insights to identify suitable mechanisms for the desired QZS feature.
{"title":"Mastering the art of designing mechanical metamaterials with quasi-zero stiffness for passive vibration isolation: a review","authors":"Ramin Hamzehei, Mahdi Bodaghi and Nan Wu","doi":"10.1088/1361-665x/ad5bcc","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5bcc","url":null,"abstract":"This review serves as a comprehensive design strategy for designing quasi-zero stiffness (QZS) mechanical metamaterials (MMs). It discusses their underlying deformation mechanisms that enable the attainment of QZS behavior under both compressive and tensile loadings. While the QZS characteristic of metamaterials has garnered considerable attention, further research is essential to unlock their potential fully. Numerous QZS metamaterials have been meticulously reviewed. They comprise various elements and mechanisms, including positive and negative stiffness elements (PS and NS), PS elements with variable stiffness, bending mechanisms employing stiff joints/areas, buckling, buckling-rotating, and bending/buckling deformation mechanisms leading to a QZS feature. Furthermore, the capability of multi-material, adaptive, smart metamaterials, origami (bending around the hinge of the folded joints), and kirigami lattices (out-of-plane buckling via cutting patterns) are weighted. These diverse mechanisms contribute to achieving QZS behavior in metamaterials under both compression and tension loads, which is paramount for various mechanical applications such as passive vibration isolation. This review effectively categorizes QZS metamaterials based on their underlying mechanisms, providing scholars with valuable insights to identify suitable mechanisms for the desired QZS feature.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"6 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141588268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-10DOI: 10.1088/1361-665x/ad5e4f
Weiguang Li, Zhichun Yang, Ximing Zhu and Ke Liu
Due to flow separation and turbulence, the slender cantilever aircraft model support system is prone to low-frequency and large-amplitude resonance in the wind tunnel tests, resulting in a decrease in test data quality, a limited test envelope, and even threatening the safe operation of the wind tunnel. A piezoelectric active damping system based on the filtered-x least mean square algorithm is proposed to effectively suppress the vibration of the wind-tunnel model support sting. Firstly, a modified variable step least mean square algorithm is proposed to address the issue that the fixed-step algorithms limit each other in terms of convergence speed and steady-state error. Following that, a variable step filtered-x least mean square algorithm based on reference signal reconstruction is developed, and the corresponding feedback controller is designed to perform the ground tests of the piezoelectric active damping system for the wind-tunnel model support sting. The experimental results show that the proposed algorithm has a faster convergence speed and lower steady-state error than the traditional algorithms, as well as strong anti-noise and adaptive control abilities that significantly improve the active vibration suppression effect of the wind-tunnel model support sting.
{"title":"Piezoelectric adaptive active vibration suppression for wind-tunnel model support sting","authors":"Weiguang Li, Zhichun Yang, Ximing Zhu and Ke Liu","doi":"10.1088/1361-665x/ad5e4f","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5e4f","url":null,"abstract":"Due to flow separation and turbulence, the slender cantilever aircraft model support system is prone to low-frequency and large-amplitude resonance in the wind tunnel tests, resulting in a decrease in test data quality, a limited test envelope, and even threatening the safe operation of the wind tunnel. A piezoelectric active damping system based on the filtered-x least mean square algorithm is proposed to effectively suppress the vibration of the wind-tunnel model support sting. Firstly, a modified variable step least mean square algorithm is proposed to address the issue that the fixed-step algorithms limit each other in terms of convergence speed and steady-state error. Following that, a variable step filtered-x least mean square algorithm based on reference signal reconstruction is developed, and the corresponding feedback controller is designed to perform the ground tests of the piezoelectric active damping system for the wind-tunnel model support sting. The experimental results show that the proposed algorithm has a faster convergence speed and lower steady-state error than the traditional algorithms, as well as strong anti-noise and adaptive control abilities that significantly improve the active vibration suppression effect of the wind-tunnel model support sting.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"21 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141586364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.1088/1361-665x/ad5caf
Lei Wang, Dukang Huang, Ke Huang, Marco Civera
The accurate and timely diagnosis of sensor faults plays a critical role in ensuring the reliability and performance of structural health monitoring (SHM) systems. However, the challenge is detecting, locating, and estimating sensor faults in an online manner using limited training data. To resolve this problem, a novel approach for online sensor fault diagnosis is proposed for SHM. The proposed approach is based on meta-learning, which enables superior model generalization capabilities using limited data. The detection, localization, and estimation of typical sensor faults in an online manner can be achieved efficiently by the proposed approach. First, a one-dimensional convolutional neural network (1D CNN) is designed to detect and locate faulty sensors. The initial model parameters of the 1D CNN are optimized using a model-agnostic meta-learning training strategy. This strategy allows the acquisition of transferable prior knowledge, which can speed up the learning process on new sensor fault detection and localization tasks. The meta-learning strategy also enables efficient and accurate detection and localization of potential faulty sensors with limited data. After detecting and locating the faulty sensors, an online updating algorithm based on a dual Kalman filter is used to estimate the severity of sensor faults and structural states simultaneously. The proposed approach is demonstrated with simulated sensor faults that cover a numerical example and field measurements from the Canton Tower. The results show that the proposed approach is applicable for online sensor fault diagnosis in SHM.
{"title":"Online meta-learning approach for sensor fault diagnosis using limited data","authors":"Lei Wang, Dukang Huang, Ke Huang, Marco Civera","doi":"10.1088/1361-665x/ad5caf","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5caf","url":null,"abstract":"The accurate and timely diagnosis of sensor faults plays a critical role in ensuring the reliability and performance of structural health monitoring (SHM) systems. However, the challenge is detecting, locating, and estimating sensor faults in an online manner using limited training data. To resolve this problem, a novel approach for online sensor fault diagnosis is proposed for SHM. The proposed approach is based on meta-learning, which enables superior model generalization capabilities using limited data. The detection, localization, and estimation of typical sensor faults in an online manner can be achieved efficiently by the proposed approach. First, a one-dimensional convolutional neural network (1D CNN) is designed to detect and locate faulty sensors. The initial model parameters of the 1D CNN are optimized using a model-agnostic meta-learning training strategy. This strategy allows the acquisition of transferable prior knowledge, which can speed up the learning process on new sensor fault detection and localization tasks. The meta-learning strategy also enables efficient and accurate detection and localization of potential faulty sensors with limited data. After detecting and locating the faulty sensors, an online updating algorithm based on a dual Kalman filter is used to estimate the severity of sensor faults and structural states simultaneously. The proposed approach is demonstrated with simulated sensor faults that cover a numerical example and field measurements from the Canton Tower. The results show that the proposed approach is applicable for online sensor fault diagnosis in SHM.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"40 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.1088/1361-665x/ad5bcd
Soyeon Kwon, Jihun Kim, Yoobin Do, Hyeokbae Kwon, Soungmin Kwon and Hyun-Taek Lee
This research provides a comprehensive exploration of the development and characterization of magnetically responsive microwall arrays (MRMAs), presenting a novel approach to precise droplet manipulation. The proposed fabrication process involves microscale wall arrays created using carbonyl iron particles embedded in polydimethylsiloxane through a replica molding process. The MRMAs demonstrate a unique response to magnetic fields, enabling precise control over droplet movement. Through superhydrophobic coatings and meticulously adjusted magnetic fields, the system facilitates the efficient movement of droplets along predefined routes, achieving outstanding accuracy in droplet directionality and positioning. The experiments highlight the capability of MRMAs to merge differently colored droplets, underscoring their potential in long-distance droplet transportation. The results suggest applications in microfluidic systems, lab-on-a-chip devices, and targeted drug delivery, marking a significant advancement in microfluidic research.
{"title":"Magnetically-responsive microwall arrays with path-guide for directional transportation of droplets","authors":"Soyeon Kwon, Jihun Kim, Yoobin Do, Hyeokbae Kwon, Soungmin Kwon and Hyun-Taek Lee","doi":"10.1088/1361-665x/ad5bcd","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5bcd","url":null,"abstract":"This research provides a comprehensive exploration of the development and characterization of magnetically responsive microwall arrays (MRMAs), presenting a novel approach to precise droplet manipulation. The proposed fabrication process involves microscale wall arrays created using carbonyl iron particles embedded in polydimethylsiloxane through a replica molding process. The MRMAs demonstrate a unique response to magnetic fields, enabling precise control over droplet movement. Through superhydrophobic coatings and meticulously adjusted magnetic fields, the system facilitates the efficient movement of droplets along predefined routes, achieving outstanding accuracy in droplet directionality and positioning. The experiments highlight the capability of MRMAs to merge differently colored droplets, underscoring their potential in long-distance droplet transportation. The results suggest applications in microfluidic systems, lab-on-a-chip devices, and targeted drug delivery, marking a significant advancement in microfluidic research.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"1 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-09DOI: 10.1088/1361-665x/ad5b31
Lei Zhang, Hu Jin, Yiming Ouyang, Wenlong Cheng, Weihua Li and Shiwu Zhang
Owing to the large strain output and high power-to-weight ratio, using temperature-induced shape memory alloy (SMA) springs in the form of antagonistic actuators offers the opportunity to develop simple, lightweight, and multi-mode robotic systems. Currently, the capabilities and deep application of these robotic systems are hindered by the relatively large resistance consumption and limited driving frequency of the antagonistic SMA actuators, primarily attributed to the cooling rate of SMA. In this paper, a spray-cooling based antagonistic SMA actuator (SCASA) was proposed, aiming to address the existing challenges in antagonistic SMA actuators. Theoretical modeling of the SCASA was comprehensively investigated. Experimental findings highlight the superior cooling efficacy of the spray-cooling method, attaining a cooling rate surpassing 100 °C per second for a single SMA spring. Using the spray-cooling based method, the driving frequency of a single SMA spring is approximately twice that of the forced-air cooling method. Experimental results also demonstrate the superior performance of the SCASA using the spray-cooling method, resulting in a reduction of approximately 50% in resistance consumption and an increase of approximately 40% in driving frequency compared to the forced-air method. This work elucidates the promising application prospects of the spray-cooling method in SMA actuators.
由于应变输出大、功率重量比高，以拮抗致动器形式使用温度诱导形状记忆合金（SMA）弹簧为开发简单、轻便和多模式机器人系统提供了机会。目前，这些机器人系统的能力和深入应用受到拮抗型 SMA 执行器相对较大的阻力消耗和有限的驱动频率的阻碍，这主要归因于 SMA 的冷却速度。本文提出了一种基于喷雾冷却的拮抗式 SMA 执行器（SCASA），旨在解决目前拮抗式 SMA 执行器所面临的挑战。本文全面研究了 SCASA 的理论建模。实验结果凸显了喷雾冷却方法的卓越冷却效果，单根 SMA 弹簧的冷却速度超过了每秒 100 °C。使用基于喷雾冷却的方法，单根 SMA 弹簧的驱动频率约为强制空气冷却方法的两倍。实验结果还表明，采用喷雾冷却方法的 SCASA 性能优越，与强制空气冷却方法相比，电阻消耗减少了约 50%，驱动频率提高了约 40%。这项工作阐明了喷雾冷却法在 SMA 执行器中的广阔应用前景。
{"title":"A spray-cooling based antagonistic SMA actuator (SCASA) with low resistance consumption and high driving frequency","authors":"Lei Zhang, Hu Jin, Yiming Ouyang, Wenlong Cheng, Weihua Li and Shiwu Zhang","doi":"10.1088/1361-665x/ad5b31","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5b31","url":null,"abstract":"Owing to the large strain output and high power-to-weight ratio, using temperature-induced shape memory alloy (SMA) springs in the form of antagonistic actuators offers the opportunity to develop simple, lightweight, and multi-mode robotic systems. Currently, the capabilities and deep application of these robotic systems are hindered by the relatively large resistance consumption and limited driving frequency of the antagonistic SMA actuators, primarily attributed to the cooling rate of SMA. In this paper, a spray-cooling based antagonistic SMA actuator (SCASA) was proposed, aiming to address the existing challenges in antagonistic SMA actuators. Theoretical modeling of the SCASA was comprehensively investigated. Experimental findings highlight the superior cooling efficacy of the spray-cooling method, attaining a cooling rate surpassing 100 °C per second for a single SMA spring. Using the spray-cooling based method, the driving frequency of a single SMA spring is approximately twice that of the forced-air cooling method. Experimental results also demonstrate the superior performance of the SCASA using the spray-cooling method, resulting in a reduction of approximately 50% in resistance consumption and an increase of approximately 40% in driving frequency compared to the forced-air method. This work elucidates the promising application prospects of the spray-cooling method in SMA actuators.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"15 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-08DOI: 10.1088/1361-665x/ad5920
Yan Wang, Lina Zhou, Lichun Cheng
This study presents a comparative analysis of Sr2Si5N8:Eu2+ nanoparticles synthesized using Spray Pyrolysis (SP) and Solid-State Synthesis (SSS). Through meticulous characterization, we found that the SP method significantly enhanced the morphological and optical properties of the nanoparticles. SP-produced nanoparticles demonstrated a 30% higher crystallinity and a 25% increase in luminescence intensity compared to their SSS counterparts. Additionally, the mesoporous structure characteristic of SP-synthesized particles exhibited a 15% greater surface area, measured at 124.7 m2 g−1, which contributed to improved light absorption capabilities. These attributes are crucial for the intended application of enhancing photosynthesis in greenhouse environments. The UV–Visible spectra confirmed that SP nanoparticles possess superior light conversion capabilities, with notable implications for optimizing light distribution to facilitate plant growth. This research highlighted the advantages of SP, including ease of scalability and enhanced optical performance, which are pivotal for agricultural applications. The study emphasized that the choice of synthesis method played a critical role in tailoring the properties of Sr2Si5N8:Eu2+ nanoparticles for specific functional requirements in optical and agricultural technologies.
{"title":"Spray pyrolysis synthesis of Sr2Si5N8:Eu2+ nanoparticles for light conversion film enhancing photosynthesis in greenhouses","authors":"Yan Wang, Lina Zhou, Lichun Cheng","doi":"10.1088/1361-665x/ad5920","DOIUrl":"https://doi.org/10.1088/1361-665x/ad5920","url":null,"abstract":"This study presents a comparative analysis of Sr<sub>2</sub>Si<sub>5</sub>N<sub>8</sub>:Eu<sup>2+</sup> nanoparticles synthesized using Spray Pyrolysis (SP) and Solid-State Synthesis (SSS). Through meticulous characterization, we found that the SP method significantly enhanced the morphological and optical properties of the nanoparticles. SP-produced nanoparticles demonstrated a 30% higher crystallinity and a 25% increase in luminescence intensity compared to their SSS counterparts. Additionally, the mesoporous structure characteristic of SP-synthesized particles exhibited a 15% greater surface area, measured at 124.7 m<sup>2</sup> g<sup>−1</sup>, which contributed to improved light absorption capabilities. These attributes are crucial for the intended application of enhancing photosynthesis in greenhouse environments. The UV–Visible spectra confirmed that SP nanoparticles possess superior light conversion capabilities, with notable implications for optimizing light distribution to facilitate plant growth. This research highlighted the advantages of SP, including ease of scalability and enhanced optical performance, which are pivotal for agricultural applications. The study emphasized that the choice of synthesis method played a critical role in tailoring the properties of Sr<sub>2</sub>Si<sub>5</sub>N<sub>8</sub>:Eu<sup>2+</sup> nanoparticles for specific functional requirements in optical and agricultural technologies.","PeriodicalId":21656,"journal":{"name":"Smart Materials and Structures","volume":"28 1","pages":""},"PeriodicalIF":4.1,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141571267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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