Pub Date : 2024-10-01DOI: 10.1016/j.ymssp.2024.111999
Wenang Jia , Wuhao Song , Hongchang Chen , Sheng Li
This study addresses the challenge in electro-hydraulic fatigue testing machines where increasing excitation frequency leads to reduced output load amplitude, making it difficult to optimize both frequency and amplitude simultaneously. A new approach is introduced with the variable resonance fatigue testing machine controlled with 2D excitation valves. This technique involves adjusting the system’s intrinsic frequency by altering its mass, aligning the excitation frequency with the intrinsic frequency, and leveraging resonance energy to enhance excitation amplitude for broad-range resonance near the resonance point. The relationship between the system’s intrinsic frequency, the equivalent mass of the upper connector, and the upper fixture is explored, yielding analytical solutions. Experimental research validates these simulations, in the resonance condition, the fatigue testing machine energy efficiency can reach 94 %, to further verify the fatigue testing machine in the resonance condition to realize the High energy efficiency. Demonstrating that the system’s intrinsic frequency decreases with increasing mass, allowing for a broad frequency resonance between 200 and 300 Hz. Operating in a broadband resonance region, the output load force is increased by 60 %–95 % and the system flow is reduced by 20 %–30 %. This mass-adjustment technique effectively alters the system’s intrinsic frequency, expanding the electro-hydraulic fatigue testing machine’s application scope.
{"title":"Advancements in electrohydraulic fatigue testing: Innovations in variable resonance frequency control and comprehensive characterization","authors":"Wenang Jia , Wuhao Song , Hongchang Chen , Sheng Li","doi":"10.1016/j.ymssp.2024.111999","DOIUrl":"10.1016/j.ymssp.2024.111999","url":null,"abstract":"<div><div>This study addresses the challenge in electro-hydraulic fatigue testing machines where increasing excitation frequency leads to reduced output load amplitude, making it difficult to optimize both frequency and amplitude simultaneously. A new approach is introduced with the variable resonance fatigue testing machine controlled with 2D excitation valves. This technique involves adjusting the system’s intrinsic frequency by altering its mass, aligning the excitation frequency with the intrinsic frequency, and leveraging resonance energy to enhance excitation amplitude for broad-range resonance near the resonance point. The relationship between the system’s intrinsic frequency, the equivalent mass of the upper connector, and the upper fixture is explored, yielding analytical solutions. Experimental research validates these simulations, in the resonance condition, the fatigue testing machine energy efficiency can reach 94 %, to further verify the fatigue testing machine in the resonance condition to realize the High energy efficiency. Demonstrating that the system’s intrinsic frequency decreases with increasing mass, allowing for a broad frequency resonance between 200 and 300 Hz. Operating in a broadband resonance region, the output load force is increased by 60 %–95 % and the system flow is reduced by 20 %–30 %. This mass-adjustment technique effectively alters the system’s intrinsic frequency, expanding the electro-hydraulic fatigue testing machine’s application scope.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"224 ","pages":"Article 111999"},"PeriodicalIF":7.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ymssp.2024.111976
Bo Zhao , Qiqiang Wu , Ke Zhao , Jipu Li , Zijun Zhang , Haidong Shao
Manipulators, particularly planar parallel manipulators, are widely employed in high-end precision equipment to conduct precise positioning and operation tasks due to their advantages of high stiffness, high precision, and high load. Moreover, they are also frequently exposed to changeable working circumstances, which significantly cause inconsistent health state data distribution. Although transfer learning can successfully offset the above distribution discrepancies, it remains unclear how to identify and quantify the source domain knowledge’s contribution to the transfer process. To overcome these challenges, a novel transfer health state diagnosis framework, named cross-receptive field fusion cascade network with adaptive mask update (CFFCN-AMU), is developed and employed for manipulators. Specifically, a unique cross-receptive field fusion cascade module (CFFCM), in which the receptive field self-evaluator and channel attention mechanism are jointly designed, is constructed initially to achieve adaptive extraction and fusion of cascaded features. Subsequently, in the target domain fine-tuning stage, an adaptive mask update (AMU) strategy is implemented to evaluate the contribution of source domain knowledge and selectively guide the parameter updating process. Finally, some mechanistic model-driven cross-working condition transfer scenarios are investigated. Multiple sets of excellent transfer diagnosis results fully illustrate the transferability and superiority of the constructed CFFCN-AMU model.
{"title":"A novel cross-receptive field fusion cascade network with adaptive mask update for transfer health state diagnosis of manipulators","authors":"Bo Zhao , Qiqiang Wu , Ke Zhao , Jipu Li , Zijun Zhang , Haidong Shao","doi":"10.1016/j.ymssp.2024.111976","DOIUrl":"10.1016/j.ymssp.2024.111976","url":null,"abstract":"<div><div>Manipulators, particularly planar parallel manipulators, are widely employed in high-end precision equipment to conduct precise positioning and operation tasks due to their advantages of high stiffness, high precision, and high load. Moreover, they are also frequently exposed to changeable working circumstances, which significantly cause inconsistent health state data distribution. Although transfer learning can successfully offset the above distribution discrepancies, it remains unclear how to identify and quantify the source domain knowledge’s contribution to the transfer process. To overcome these challenges, a novel transfer health state diagnosis framework, named cross-receptive field fusion cascade network with adaptive mask update (CFFCN-AMU), is developed and employed for manipulators. Specifically, a unique cross-receptive field fusion cascade module (CFFCM), in which the receptive field self-evaluator and channel attention mechanism are jointly designed, is constructed initially to achieve adaptive extraction and fusion of cascaded features. Subsequently, in the target domain fine-tuning stage, an adaptive mask update (AMU) strategy is implemented to evaluate the contribution of source domain knowledge and selectively guide the parameter updating process. Finally, some mechanistic model-driven cross-working condition transfer scenarios are investigated. Multiple sets of excellent transfer diagnosis results fully illustrate the transferability and superiority of the constructed CFFCN-AMU model.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"224 ","pages":"Article 111976"},"PeriodicalIF":7.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ymssp.2024.111951
Lei Zhang , Xuhui Zhang , Hua Xu
Adjustable/controllable bearings are the future direction of journal bearings and are used to correct design blind spots and handle changing operating conditions. This study investigates a clearance-adjustable bearing structure and its adjustment method to improve the operating stability of a rotor system under different working conditions. The theoretical model of this adjustable journal bearing was constructed and its lubricating characteristics under different clearances are analyzed. The Reynolds equation and the rotor dynamics equation were coupled to calculate the oil film force of the adjustable bearing introduced into the rotor system. The effect of the adjustable bearings on the dynamic response of the rigid rotor was investigated under different speeds and loads. Further, the adjustment methods required to improve the operation of the rigid rotor system were identified. Consequently, a finite element model of the adjustable bearing-rotor system was established to study the effect of the adjustable bearing on the dynamic behavior of the slender rotor system. In addition, the vibration response of the slender rotor within different speed regions was analyzed and the reasons for the change in amplitude owing to bearing clearance adjustment were explained. Furthermore, the corresponding test bench was constructed for experimental verification, and the essence of the adjustable bearing changing the dynamic response of the rotor system was described.
{"title":"Theoretical and experimental study on the effect of adjustable journal bearings on the vibration response of rigid and slender rotor systems","authors":"Lei Zhang , Xuhui Zhang , Hua Xu","doi":"10.1016/j.ymssp.2024.111951","DOIUrl":"10.1016/j.ymssp.2024.111951","url":null,"abstract":"<div><div>Adjustable/controllable bearings are the future direction of journal bearings and are used to correct design blind spots and handle changing operating conditions. This study investigates a clearance-adjustable bearing structure and its adjustment method to improve the operating stability of a rotor system under different working conditions. The theoretical model of this adjustable journal bearing was constructed and its lubricating characteristics under different clearances are analyzed. The Reynolds equation and the rotor dynamics equation were coupled to calculate the oil film force of the adjustable bearing introduced into the rotor system. The effect of the adjustable bearings on the dynamic response of the rigid rotor was investigated under different speeds and loads. Further, the adjustment methods required to improve the operation of the rigid rotor system were identified. Consequently, a finite element model of the adjustable bearing-rotor system was established to study the effect of the adjustable bearing on the dynamic behavior of the slender rotor system. In addition, the vibration response of the slender rotor within different speed regions was analyzed and the reasons for the change in amplitude owing to bearing clearance adjustment were explained. Furthermore, the corresponding test bench was constructed for experimental verification, and the essence of the adjustable bearing changing the dynamic response of the rotor system was described.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"224 ","pages":"Article 111951"},"PeriodicalIF":7.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-30DOI: 10.1016/j.ymssp.2024.111964
Jia-Yi Xi , Tian-Chen Yuan , Jian Yang , Ruigang Song , Yu Fang , Li-Qun Chen
A vibration energy harvester can collect vibration energy from the environment to supply low-power devices, such as wireless sensor nodes. Reducing the size and power consumption of these devices is a challenging problem. A dual-function device, which includes energy harvesting and vibration measurement, may solve this problem. Therefore, studying inversion methods for identifying the external excitation of a harvester is meaningful. In this study, a modified inversion method that combines an extended Rauch–Tung–Striebel smoother (ERTSS) with the particle swarm optimization (PSO) algorithm, i.e., the ERTSS-PSO method, is proposed to identify the time domain signal of external excitation through the voltage response of a piezoelectric vibration energy harvester. A modified ERTSS approach with sliding windows is developed. The sliding windows are partially overlapped to eliminate identification errors between the two contiguous windows. Near real-time identification is achieved for the small sliding window. PSO is utilized to estimate state noise covariance and measurement noise covariance, improving identification accuracy compared with the L-curve approach. Under this proposed framework, prior knowledge regarding the statistical data of unknown external excitations is unnecessary, enabling a more comprehensive range of applications. To assess the performance of the proposed ERTSS-PSO method, numerical simulations, including two piezoelectric vibration energy harvesting systems with third-order and fifth-order nonlinear stiffness, are conducted to verify the effectiveness of the proposed method under harmonic, multifrequency, and random excitations. The method proposed in this study is also validated by a circular laminated piezoelectric plate harvester under harmonic and random excitations in an experiment. Results from the experimental studies demonstrate that the proposed method improves identification accuracy by at least 9% compared with the extended Kalman filter, at least 7% compared with the augmented Kalman filter (AKF) with Rauch–Tung–Striebel smoother (ARTSS), and at least 40% compared with AKF under random excitation. In addition, the proposed method is unaffected by initial conditions, and it is more stable and accurate than AKF and ARTSS. The proposed method lays the theoretical foundation for identifying the external excitation of a harvester. It is also a possible solution for the miniaturization and compactness of wireless monitoring devices.
{"title":"Modified extended Rauch–Tung–Striebel smoother method for the dynamic external excitation identification of piezoelectric vibration energy harvesting systems","authors":"Jia-Yi Xi , Tian-Chen Yuan , Jian Yang , Ruigang Song , Yu Fang , Li-Qun Chen","doi":"10.1016/j.ymssp.2024.111964","DOIUrl":"10.1016/j.ymssp.2024.111964","url":null,"abstract":"<div><div>A vibration energy harvester can collect vibration energy from the environment to supply low-power devices, such as wireless sensor nodes. Reducing the size and power consumption of these devices is a challenging problem. A dual-function device, which includes energy harvesting and vibration measurement, may solve this problem. Therefore, studying inversion methods for identifying the external excitation of a harvester is meaningful. In this study, a modified inversion method that combines an extended Rauch–Tung–Striebel smoother (ERTSS) with the particle swarm optimization (PSO) algorithm, i.e., the ERTSS-PSO method, is proposed to identify the time domain signal of external excitation through the voltage response of a piezoelectric vibration energy harvester. A modified ERTSS approach with sliding windows is developed. The sliding windows are partially overlapped to eliminate identification errors between the two contiguous windows. Near real-time identification is achieved for the small sliding window. PSO is utilized to estimate state noise covariance and measurement noise covariance, improving identification accuracy compared with the L-curve approach. Under this proposed framework, prior knowledge regarding the statistical data of unknown external excitations is unnecessary, enabling a more comprehensive range of applications. To assess the performance of the proposed ERTSS-PSO method, numerical simulations, including two piezoelectric vibration energy harvesting systems with third-order and fifth-order nonlinear stiffness, are conducted to verify the effectiveness of the proposed method under harmonic, multifrequency, and random excitations. The method proposed in this study is also validated by a circular laminated piezoelectric plate harvester under harmonic and random excitations in an experiment. Results from the experimental studies demonstrate that the proposed method improves identification accuracy by at least 9% compared with the extended Kalman filter, at least 7% compared with the augmented Kalman filter (AKF) with Rauch–Tung–Striebel smoother (ARTSS), and at least 40% compared with AKF under random excitation. In addition, the proposed method is unaffected by initial conditions, and it is more stable and accurate than AKF and ARTSS. The proposed method lays the theoretical foundation for identifying the external excitation of a harvester. It is also a possible solution for the miniaturization and compactness of wireless monitoring devices.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"224 ","pages":"Article 111964"},"PeriodicalIF":7.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-30DOI: 10.1016/j.ymssp.2024.111987
Haizhou Shi , Kai Zhang , Xiangbing Liu , Liyuan Qi , Fang Hong , Zichen Deng
In recent years, the deployment and vibration suppression capabilities of spacecraft have become one of the prominent research topics. Considerable effort has been dedicated to studying the deployability and vibration suppression performance of origami structures. However, traditional origami types severely limit their application in aerospace engineering due to their unique deployment behavior. This study introduces a novel meta-structure with hybridization of Kresling origami and Yoshimura origami (MHKYO), designed to suppress low-frequency vibrations. The band structure and transmission rate of the proposed metastructure were studied to evaluate its vibration suppression performance. The adjustment of the bandgap of the metastructure was achieved through geometric parameter variation. Quasi-static compression experiments and transmission rate experiments were carried out, and the results obtained were almost consistent with those obtained by finite element methods. During the compression process, the origami metastructure exhibited quasi-zero-stiffness (QZS) behavior. The influence of the metastructure’s stiffness on the band structure was analyzed. It is also proved that the hybrid origami metastructure improves the vibration suppression performance of the traditional origami metastructure. This work proposes a new origami-inspired metastructure, providing a certain theoretical basis for the application of origami technology in aerospace engineering.
{"title":"Vibration suppression of a meta-structure with hybridization of Kresling origami and Yoshimura origami","authors":"Haizhou Shi , Kai Zhang , Xiangbing Liu , Liyuan Qi , Fang Hong , Zichen Deng","doi":"10.1016/j.ymssp.2024.111987","DOIUrl":"10.1016/j.ymssp.2024.111987","url":null,"abstract":"<div><div>In recent years, the deployment and vibration suppression capabilities of spacecraft have become one of the prominent research topics. Considerable effort has been dedicated to studying the deployability and vibration suppression performance of origami structures. However, traditional origami types severely limit their application in aerospace engineering due to their unique deployment behavior. This study introduces a novel meta-structure with hybridization of Kresling origami and Yoshimura origami (MHKYO), designed to suppress low-frequency vibrations. The band structure and transmission rate of the proposed metastructure were studied to evaluate its vibration suppression performance. The adjustment of the bandgap of the metastructure was achieved through geometric parameter variation. Quasi-static compression experiments and transmission rate experiments were carried out, and the results obtained were almost consistent with those obtained by finite element methods. During the compression process, the origami metastructure exhibited quasi-zero-stiffness (QZS) behavior. The influence of the metastructure’s stiffness on the band structure was analyzed. It is also proved that the hybrid origami metastructure improves the vibration suppression performance of the traditional origami metastructure. This work proposes a new origami-inspired metastructure, providing a certain theoretical basis for the application of origami technology in aerospace engineering.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"224 ","pages":"Article 111987"},"PeriodicalIF":7.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-30DOI: 10.1016/j.ymssp.2024.111975
Yingli Li , Guohui Yin , Gengwang Yan , Song Yao
Phononic crystals are novel artificial materials characterized by the periodic arrangement of elastic materials within another elastic medium, which imparts exceptional features to the material, including the presence of band gaps. In order to obtain the phononic crystal structure possessing the desired features, standard design approaches typically involve iterative searches within an extensive design space which necessitates significant processing resources and expenses. This study introduces a novel approach, combining a convolutional autoencoder with deep neural network, to extract topological features of phononic crystal samples and conduct forward prediction of band gap distributions. Subsequently, the trained forward prediction model is employed as a substitute for finite element simulations to expedite the computation of the genetic algorithm’s fitness. For the first time, this study introduced a chromosome coding expansion strategy and a fitness gradient strategy which can effectively avoid the issue of stagnation occurring during the initial population evolution. In the on-demand design, the band gap average loss ratio amounts to 5.9%, while the average excess proportion stands at 8.92%. The computation time for this method is 7.5 times shorter than that of method using a genetic algorithm with a finite element model, based on the six cases prediction. The band gap frequency of the optimum structure with proposed method is 2.7 times lower and 73 times broader compared to the classical phononic crystal with square-shaped scatter with almost twice volume fraction, which less degrades the strength. This interactive approach offers a solution to the issue of the nonunique response-to-design mapping problem. This method is not solely restricted to on-demand design, but also has the capability to optimize the band gap of phononic crystals with specific configurations under constrained conditions. This advancement sets the stage for the development of a forward-backstepping interactive design approach for metamaterials.
{"title":"Forward-backstepping design of phononic crystals with anticipated band gap by data-driven method","authors":"Yingli Li , Guohui Yin , Gengwang Yan , Song Yao","doi":"10.1016/j.ymssp.2024.111975","DOIUrl":"10.1016/j.ymssp.2024.111975","url":null,"abstract":"<div><div>Phononic crystals are novel artificial materials characterized by the periodic arrangement of elastic materials within another elastic medium, which imparts exceptional features to the material, including the presence of band gaps. In order to obtain the phononic crystal structure possessing the desired features, standard design approaches typically involve iterative searches within an extensive design space which necessitates significant processing resources and expenses. This study introduces a novel approach, combining a convolutional autoencoder with deep neural network, to extract topological features of phononic crystal samples and conduct forward prediction of band gap distributions. Subsequently, the trained forward prediction model is employed as a substitute for finite element simulations to expedite the computation of the genetic algorithm’s fitness. For the first time, this study introduced a chromosome coding expansion strategy and a fitness gradient strategy which can effectively avoid the issue of stagnation occurring during the initial population evolution. In the on-demand design, the band gap average loss ratio amounts to 5.9%, while the average excess proportion stands at 8.92%. The computation time for this method is 7.5 times shorter than that of method using a genetic algorithm with a finite element model, based on the six cases prediction. The band gap frequency of the optimum structure with proposed method is 2.7 times lower and 73 times broader compared to the classical phononic crystal with square-shaped scatter with almost twice volume fraction, which less degrades the strength. This interactive approach offers a solution to the issue of the nonunique response-to-design mapping problem. This method is not solely restricted to on-demand design, but also has the capability to optimize the band gap of phononic crystals with specific configurations under constrained conditions. This advancement sets the stage for the development of a forward-backstepping interactive design approach for metamaterials.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"224 ","pages":"Article 111975"},"PeriodicalIF":7.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-30DOI: 10.1016/j.ymssp.2024.111989
Yusheng Ma , Saeid Hedayatrasa , Adil Han Orta , Koen Van Den Abeele , Mathias Kersemans
The Delay and Sum (DAS) method is a well-known damage imaging technique in sparse array guided wave imaging. However, the DAS method requires prior knowledge on the stable baseline state, which makes it ineffective under different operational or environmental conditions, e.g. temperature and moisture, and altered experimental settings, e.g. degraded bonding quality of sensors.
This paper proposes a Nonlinear Delay and Sum (NL-DAS) method which does not require prior knowledge about the baseline state, but instead exploits the presence of nonlinear wave/defect interactions. Relatively high-power broadband sweep sine signals are supplied to a sparse sensor array to activate a multitude of nonlinear wave/defect interactions. Application of time–frequency filtering to the response signals allows the isolation of damage-induced broadband nonlinear responses. The isolated broadband nonlinear response signals are subsequently decomposed into a series of narrowband tone burst responses from which a set of damage maps are constructed. To improve the quality of the constructed damage maps, an automated framework is proposed to obtain the frequency-dependent directional group velocities without requiring prior knowledge on material properties. Finally, the resulting set of damage maps is fused into a single broadband NL-DAS damage map.
The proposed broadband NL-DAS approach is demonstrated on a simulation dataset, generated with 3D Finite Element method, which is representative for a cross-ply carbon fiber reinforced polymer (CFRP) containing a delamination defect. The damage imaging performance is studied for different test conditions in terms of (i) signal-to-noise ratio, (ii) number of sensors and (iii) excitation bandwidth. Experimental validation is illustrated on a CFRP plate containing a barely visible impact damage, and on a CFRP A320 component with a disbond at one of the stiffeners.
{"title":"Broadband nonlinear delay and sum (NL-DAS) for baseline-free damage imaging using a sparse sensor network","authors":"Yusheng Ma , Saeid Hedayatrasa , Adil Han Orta , Koen Van Den Abeele , Mathias Kersemans","doi":"10.1016/j.ymssp.2024.111989","DOIUrl":"10.1016/j.ymssp.2024.111989","url":null,"abstract":"<div><div>The Delay and Sum (DAS) method is a well-known damage imaging technique in sparse array guided wave imaging. However, the DAS method requires prior knowledge on the stable baseline state, which makes it ineffective under different operational or environmental conditions, e.g. temperature and moisture, and altered experimental settings, e.g. degraded bonding quality of sensors.</div><div>This paper proposes a Nonlinear Delay and Sum (NL-DAS) method which does not require prior knowledge about the baseline state, but instead exploits the presence of nonlinear wave/defect interactions. Relatively high-power broadband sweep sine signals are supplied to a sparse sensor array to activate a multitude of nonlinear wave/defect interactions. Application of time–frequency filtering to the response signals allows the isolation of damage-induced broadband nonlinear responses. The isolated broadband nonlinear response signals are subsequently decomposed into a series of narrowband tone burst responses from which a set of damage maps are constructed. To improve the quality of the constructed damage maps, an automated framework is proposed to obtain the frequency-dependent directional group velocities without requiring prior knowledge on material properties. Finally, the resulting set of damage maps is fused into a single broadband NL-DAS damage map.</div><div>The proposed broadband NL-DAS approach is demonstrated on a simulation dataset, generated with 3D Finite Element method, which is representative for a cross-ply carbon fiber reinforced polymer (CFRP) containing a delamination defect. The damage imaging performance is studied for different test conditions in terms of (i) signal-to-noise ratio, (ii) number of sensors and (iii) excitation bandwidth. Experimental validation is illustrated on a CFRP plate containing a barely visible impact damage, and on a CFRP A320 component with a disbond at one of the stiffeners.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"224 ","pages":"Article 111989"},"PeriodicalIF":7.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-30DOI: 10.1016/j.ymssp.2024.111988
Yuhao Zhang, Wei Pu
Dynamic actuation accuracy of ball screws is dramatically affected by screw flexible deformation and the behaviors of ball-groove interface such as friction, stiffness and damping. However, few dynamics studies have considered the screw flexible deformation and rubbing interface behaviors in ball screws. In this study, a dynamics model is developed by including both the screw flexible deformation and lubrication interface behavior. Discretization of the screw/nut is completed using the 6 degree-of-freedom Timoshenko beam element. The tribological properties of ball-groove interface are solved by the mixed lubrication model. Comparison with experimentally tested nut acceleration frequencies verifies the correctness of theoretical model. On this basis, the effects of nut motion, nut position and rough surface on the dynamic response are analyzed. With the increase of time, the screw axial displacement decreases with a certain slope and is accompanied by periodic vibrations. The centers of axis trajectories at different nut positions are far apart. From Hertz, smooth surface to rough surface, the interface stiffness coefficient decreases and the nut vibration amplitude grows. The novel tribo-dynamics model can provide a theoretical basis for fault diagnosis and performance optimization of ball screws.
{"title":"A tribo-dynamics model of ball screws based on flexible body element","authors":"Yuhao Zhang, Wei Pu","doi":"10.1016/j.ymssp.2024.111988","DOIUrl":"10.1016/j.ymssp.2024.111988","url":null,"abstract":"<div><div>Dynamic actuation accuracy of ball screws is dramatically affected by screw flexible deformation and the behaviors of ball-groove interface such as friction, stiffness and damping. However, few dynamics studies have considered the screw flexible deformation and rubbing interface behaviors in ball screws. In this study, a dynamics model is developed by including both the screw flexible deformation and lubrication interface behavior. Discretization of the screw/nut is completed using the 6 degree-of-freedom Timoshenko beam element. The tribological properties of ball-groove interface are solved by the mixed lubrication model. Comparison with experimentally tested nut acceleration frequencies verifies the correctness of theoretical model. On this basis, the effects of nut motion, nut position and rough surface on the dynamic response are analyzed. With the increase of time, the screw axial displacement decreases with a certain slope and is accompanied by periodic vibrations. The centers of axis trajectories at different nut positions are far apart. From Hertz, smooth surface to rough surface, the interface stiffness coefficient decreases and the nut vibration amplitude grows. The novel tribo-dynamics model can provide a theoretical basis for fault diagnosis and performance optimization of ball screws.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"224 ","pages":"Article 111988"},"PeriodicalIF":7.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-30DOI: 10.1016/j.ymssp.2024.111981
Jing-wei Zhou , Zhaoye Qin , Endi Zhai , Zhongpeng Liu , Suyu Wang , Yunfei Liu , Tianyang Wang , Fulei Chu
This study proposes a new methodology for optimizing the power curve of a wind turbine at low wind speeds. The principles of bend-twist coupling and the mechanism of energy exchange between the structure and inflow are analyzed. For the blade’s geometric nonlinearity, the virtual displacements and strain fields are described using the Green-Lagrange strain theorem, retaining third-order terms in the energy expressions. The equations of motion are derived using Hamilton’s principle. The bend-twist coupling effects and large deformations of the blade are analyzed using the Updated Lagrange method. Notably, the angle of attack for a single blade section is influenced by bend-twist deformation, causing variations in the rotor’s maximum power coefficient from its optimal value. Additionally, the projection length of the blade, influenced by centrifugal forces, also affects the bend-twist deformation. Based on these findings, an aero-elastic coupling control strategy, termed “Bend-twist Adaptive Control”, is proposed and validated through experiments. The results demonstrate that the proposed control strategy could increase annual power production by 2.3 %. These conclusions offer a promising outlook for future wind turbine blade design and power optimization.
{"title":"Bend-twist adaptive control for flexible wind turbine blades: Principles and experimental validation","authors":"Jing-wei Zhou , Zhaoye Qin , Endi Zhai , Zhongpeng Liu , Suyu Wang , Yunfei Liu , Tianyang Wang , Fulei Chu","doi":"10.1016/j.ymssp.2024.111981","DOIUrl":"10.1016/j.ymssp.2024.111981","url":null,"abstract":"<div><div>This study proposes a new methodology for optimizing the power curve of a wind turbine at low wind speeds. The principles of bend-twist coupling and the mechanism of energy exchange between the structure and inflow are analyzed. For the blade’s geometric nonlinearity, the virtual displacements and strain fields are described using the Green-Lagrange strain theorem, retaining third-order terms in the energy expressions. The equations of motion are derived using Hamilton’s principle. The bend-twist coupling effects and large deformations of the blade are analyzed using the Updated Lagrange method. Notably, the angle of attack for a single blade section is influenced by bend-twist deformation, causing variations in the rotor’s maximum power coefficient from its optimal value. Additionally, the projection length of the blade, influenced by centrifugal forces, also affects the bend-twist deformation. Based on these findings, an aero-elastic coupling control strategy, termed “Bend-twist Adaptive Control”, is proposed and validated through experiments. The results demonstrate that the proposed control strategy could increase annual power production by 2.3 %. These conclusions offer a promising outlook for future wind turbine blade design and power optimization.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"224 ","pages":"Article 111981"},"PeriodicalIF":7.9,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-29DOI: 10.1016/j.ymssp.2024.111980
Yang Zhou , Yuanping Xu , Jin Zhou , Yue Zhang , Jarir Mahfoud
Rotor-Active Magnetic Bearings (rotor-AMBs) systems nowadays have been widely used in turbomachinery where different methods for assembly were used such as impeller mounted using shrink-fit. In our experiments we noticed that the conditions of shrink-ft assembly can introduce instabilities on the levitated rotor at rest. To understand and give recommendations (on the assembly conditions), a numerical model was developed and then was validated experimentally. The effect of the shrink-fit interface contact was modelled as a contact force acting on the rotor-AMBs system introduced by distributed spring units with a given contact stiffness. Considering that there was partial separation in the contact interface due to the AMBs levitating forces, a novel contact force model related to contact status was established by calculating the real-time contact area. A microscopic contact model based on fractal theory was developed to calculate the contact stiffness. The model developed was then validated experimentally simulating the levitating rotor at rest. The rotor response was analyzed in frequency domains by applying the different conditions of shrink-fit interference and contact length. The shrink-fit contact conditions influenced the system stability and made the fourth bending mode unstable. The increase of shrink-fit interference and contact length decreased closed-loop system stability and increased the amplitude of the rotor vibration response. The model reliability was assessed and a stable region using combinations of shrink-fit parameters on the assembly conditions based on the results of stability analysis was established.
{"title":"Numerical and experimental investigations on the dynamic behavior of a rotor-AMBs system considering shrink-fit assembly","authors":"Yang Zhou , Yuanping Xu , Jin Zhou , Yue Zhang , Jarir Mahfoud","doi":"10.1016/j.ymssp.2024.111980","DOIUrl":"10.1016/j.ymssp.2024.111980","url":null,"abstract":"<div><div>Rotor-Active Magnetic Bearings (rotor-AMBs) systems nowadays have been widely used in turbomachinery where different methods for assembly were used such as impeller mounted using shrink-fit. In our experiments we noticed that the conditions of shrink-ft assembly can introduce instabilities on the levitated rotor at rest. To understand and give recommendations (on the assembly conditions), a numerical model was developed and then was validated experimentally. The effect of the shrink-fit interface contact was modelled as a contact force acting on the rotor-AMBs system introduced by distributed spring units with a given contact stiffness. Considering that there was partial separation in the contact interface due to the AMBs levitating forces, a novel contact force model related to contact status was established by calculating the real-time contact area. A microscopic contact model based on fractal theory was developed to calculate the contact stiffness. The model developed was then validated experimentally simulating the levitating rotor at rest. The rotor response was analyzed in frequency domains by applying the different conditions of shrink-fit interference and contact length. The shrink-fit contact conditions influenced the system stability and made the fourth bending mode unstable. The increase of shrink-fit interference and contact length decreased closed-loop system stability and increased the amplitude of the rotor vibration response. The model reliability was assessed and a stable region using combinations of shrink-fit parameters on the assembly conditions based on the results of stability analysis was established.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"224 ","pages":"Article 111980"},"PeriodicalIF":7.9,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142357142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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