Pub Date : 2024-11-12DOI: 10.1016/j.ymssp.2024.112106
Xinghui Han, Yi Lu, Fangyan Zheng, Lin Hua, Dahu Zhu, Xin Chen
Regenerative chatter is an unstable and detrimental vibration phenomenon stemming from the regenerative excitation of time-delay dynamic systems. Currently, research on regenerative chatter predominantly focuses on machining process, wherein chatter occurs when the process frequency aligns closely with the natural frequency of the tool-holder system. However, in plastic forming process conducted by heavy-load multi-DoF forming machine (MDFM), the process frequency is far smaller than the natural frequency of the tool-holder system. Despite this, chatter still occurs in the actual plastic forming process, challenging the explanatory capacity of existing chatter models developed for machining process.
{"title":"Modelling and analysis of chatter in the heavy-load multi-DoF plastic forming process","authors":"Xinghui Han, Yi Lu, Fangyan Zheng, Lin Hua, Dahu Zhu, Xin Chen","doi":"10.1016/j.ymssp.2024.112106","DOIUrl":"https://doi.org/10.1016/j.ymssp.2024.112106","url":null,"abstract":"Regenerative chatter is an unstable and detrimental vibration phenomenon stemming from the regenerative excitation of time-delay dynamic systems. Currently, research on regenerative chatter predominantly focuses on machining process, wherein chatter occurs when the process frequency aligns closely with the natural frequency of the tool-holder system. However, in plastic forming process conducted by heavy-load multi-DoF forming machine (MDFM), the process frequency is far smaller than the natural frequency of the tool-holder system. Despite this, chatter still occurs in the actual plastic forming process, challenging the explanatory capacity of existing chatter models developed for machining process.","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"106 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665628","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 : 2024-11-12DOI: 10.1016/j.ymssp.2024.112110
Boyu Cai, Qihang Qin, Xun Wang, Jing Lin
Bolt joints are commonly used in aviation structures. Bolt looseness may pose serious safety risks and its online monitoring is of great importance to structure and air safety. Active guided wave detection methods can accurately identify the tightness status of bolts. However, the excitation of active guided waves requires big and heavy equipment, such as waveform generators and power amplifiers, which are often not allowed due to the lightweight design of aircraft. It is found that random ultrasonic guided waves can be passively excited by the coupling between airflow and airframe, which carries rich structural health information and has great potential for passive online detection of aircraft structure. In this paper, the cross-correlation function between random guided waves measured by two passive receivers is computed to identify the wave propagation paths in a bolt joint structure and the wave energy along each path passing through a bolt, by which the bolt tightness is assessed. Laboratory and wind tunnel experiments show that a broadband random ultrasonic guided wave can be excited due to the interaction of airflow with an airframe structure, from which the proposed method can efficiently identify the looseness of multiple bolts.
{"title":"Passive detection of bolt joint looseness using flow-induced ambient noise","authors":"Boyu Cai, Qihang Qin, Xun Wang, Jing Lin","doi":"10.1016/j.ymssp.2024.112110","DOIUrl":"https://doi.org/10.1016/j.ymssp.2024.112110","url":null,"abstract":"Bolt joints are commonly used in aviation structures. Bolt looseness may pose serious safety risks and its online monitoring is of great importance to structure and air safety. Active guided wave detection methods can accurately identify the tightness status of bolts. However, the excitation of active guided waves requires big and heavy equipment, such as waveform generators and power amplifiers, which are often not allowed due to the lightweight design of aircraft. It is found that random ultrasonic guided waves can be passively excited by the coupling between airflow and airframe, which carries rich structural health information and has great potential for passive online detection of aircraft structure. In this paper, the cross-correlation function between random guided waves measured by two passive receivers is computed to identify the wave propagation paths in a bolt joint structure and the wave energy along each path passing through a bolt, by which the bolt tightness is assessed. Laboratory and wind tunnel experiments show that a broadband random ultrasonic guided wave can be excited due to the interaction of airflow with an airframe structure, from which the proposed method can efficiently identify the looseness of multiple bolts.","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"101 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665645","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}
In consideration of significant uncertainties arising from the degradation of in-service train-slab track-bridge coupled systems and the limitation in accurately reproducing track irregularities using prescribed track spectra, this study presents a novel framework to establish a digital twin for dynamics of an in-service train-slab track-bridge coupled system to best simulate and predict its dynamic behavior and performance during its operation. The train-slab track-bridge coupled system of a railway test line is taken as a physical entity and subjected to field measurements. The design-document-based virtual entity (numerical model) of the train-slab track-bridge coupled system is then established. A model updating procedure is subsequently proposed for the virtual entity based on the dynamic characteristics identified from the physical entity, and a track irregularity spectrum recognition method is developed in terms of the measured dynamic responses and optimization algorithm, thereby leading to the digital twin establishment. The established digital twin is finally used to simulate and predict the coupled vibration of the train-slab track-bridge system and compare with the measurement results. The results demonstrate the feasibility and accuracy of the digital twin and its prediction capability.
{"title":"Digital twins for dynamics of a train-slab track-bridge coupled system","authors":"Hao Liang, Bao-Rui Dai, You-Lin Xu, Qi Li, Qing-Yuan Song, Yue Zheng","doi":"10.1016/j.ymssp.2024.112130","DOIUrl":"https://doi.org/10.1016/j.ymssp.2024.112130","url":null,"abstract":"In consideration of significant uncertainties arising from the degradation of in-service train-slab track-bridge coupled systems and the limitation in accurately reproducing track irregularities using prescribed track spectra, this study presents a novel framework to establish a digital twin for dynamics of an in-service train-slab track-bridge coupled system to best simulate and predict its dynamic behavior and performance during its operation. The train-slab track-bridge coupled system of a railway test line is taken as a physical entity and subjected to field measurements. The design-document-based virtual entity (numerical model) of the train-slab track-bridge coupled system is then established. A model updating procedure is subsequently proposed for the virtual entity based on the dynamic characteristics identified from the physical entity, and a track irregularity spectrum recognition method is developed in terms of the measured dynamic responses and optimization algorithm, thereby leading to the digital twin establishment. The established digital twin is finally used to simulate and predict the coupled vibration of the train-slab track-bridge system and compare with the measurement results. The results demonstrate the feasibility and accuracy of the digital twin and its prediction capability.","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"12 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665640","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}
To address the recurring vibration in the integrated unit-plant structure system during the transitional phases of pumped storage power station (PSPS), the magnetorheological damper (MRD) is introduced in this paper to investigate transient vibration control within the coupled unit-plant structure (CUPS). Firstly, taking an actual PSPS as a case study, a unit regulation system model is developed based on one-dimensional transient flow theory, the method of characteristics (MOC), and the improved Suter transformation. Secondly, integrating the position function of unit shaft system, a nonlinear dynamic model of MRD is constructed, and the MRD damping force accounting for axial position parameters is derived. Additionally, on the basis of Lagrange method and finite element method, a mathematical model of unit shaft system and a finite element model for plant structure under the coupling effects of multiple vibration sources are established. Finally, the response to a sudden 10% load increase in generator condition of pumped storage unit is calculated through numerical simulation, and the effects of different damper position functions on the vibration characteristics of rotor and runner are analyzed to identify the optimal installation position for effective vibration control. The research results indicate that, optimizing the damper layout position enables the MRD to effectively reduce the vibration amplitude of rotor and runner, enhancing spectral characteristics. Furthermore, optimizing MRD positions significantly improves the vibration performance of plant structure. After the optimization of MRD positions, the vibration attenuation rate of plant structure accelerates, leading to a quicker stabilization, particularly noticeable in the generator floor. The findings of this study offer valuable engineering guidance for managing transient vibration in the integrated unit-plant system of PSPS.
{"title":"Transient vibration control on coupled unit-plant structure of pumped storage power station based on MRD optimal layout","authors":"Jinjian Zhang, Zhenyue Ma, Wenjie Xu, Xueni Wang, Kaiwen Zhang, Leike Zhang","doi":"10.1016/j.ymssp.2024.112111","DOIUrl":"https://doi.org/10.1016/j.ymssp.2024.112111","url":null,"abstract":"To address the recurring vibration in the integrated unit-plant structure system during the transitional phases of pumped storage power station (PSPS), the magnetorheological damper (MRD) is introduced in this paper to investigate transient vibration control within the coupled unit-plant structure (CUPS). Firstly, taking an actual PSPS as a case study, a unit regulation system model is developed based on one-dimensional transient flow theory, the method of characteristics (MOC), and the improved Suter transformation. Secondly, integrating the position function of unit shaft system, a nonlinear dynamic model of MRD is constructed, and the MRD damping force accounting for axial position parameters is derived. Additionally, on the basis of Lagrange method and finite element method, a mathematical model of unit shaft system and a finite element model for plant structure under the coupling effects of multiple vibration sources are established. Finally, the response to a sudden 10% load increase in generator condition of pumped storage unit is calculated through numerical simulation, and the effects of different damper position functions on the vibration characteristics of rotor and runner are analyzed to identify the optimal installation position for effective vibration control. The research results indicate that, optimizing the damper layout position enables the MRD to effectively reduce the vibration amplitude of rotor and runner, enhancing spectral characteristics. Furthermore, optimizing MRD positions significantly improves the vibration performance of plant structure. After the optimization of MRD positions, the vibration attenuation rate of plant structure accelerates, leading to a quicker stabilization, particularly noticeable in the generator floor. The findings of this study offer valuable engineering guidance for managing transient vibration in the integrated unit-plant system of PSPS.","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"73 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665643","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}
Flexible rotor systems with spline joints often encounter critical resonances and sudden self-excited vibrations. This paper introduces an innovative state-switching scheme utilizing auxiliary support with a pre-loaded snubber ring to suppress these undesirable vibrations. A prototype of an auxiliary support was designed, and a coupled rotor dynamics model incorporating a nonlinear auxiliary support was developed. The study presents several numerical examples and experimental results that validate the effectiveness of the proposed method. Adjusting design parameters such as initial clearance and leaf spring stiffness demonstrated significant improvements in limiting shaft amplitude and shifting the resonance frequency to higher ranges. Additional damping from the support further aids in reducing vibrations. The auxiliary support successfully attenuated self-excited vibrations within the supercritical speed range, achieving only short-term oscillations and restricting amplitude within set limits. This novel approach offers a promising solution for suppressing both first-order resonance and self-excited vibrations in flexible rotor systems, thereby enhancing overall system performance and stability.
{"title":"Vibration mitigation in a spline-shafting system via an auxiliary support: Simulation and experiment","authors":"Xinxing Ma, Rihuan Yu, Hongwu Li, Jianping Jing, Zhenguo Zhang","doi":"10.1016/j.ymssp.2024.112120","DOIUrl":"https://doi.org/10.1016/j.ymssp.2024.112120","url":null,"abstract":"Flexible rotor systems with spline joints often encounter critical resonances and sudden self-excited vibrations. This paper introduces an innovative state-switching scheme utilizing auxiliary support with a pre-loaded snubber ring to suppress these undesirable vibrations. A prototype of an auxiliary support was designed, and a coupled rotor dynamics model incorporating a nonlinear auxiliary support was developed. The study presents several numerical examples and experimental results that validate the effectiveness of the proposed method. Adjusting design parameters such as initial clearance and leaf spring stiffness demonstrated significant improvements in limiting shaft amplitude and shifting the resonance frequency to higher ranges. Additional damping from the support further aids in reducing vibrations. The auxiliary support successfully attenuated self-excited vibrations within the supercritical speed range, achieving only short-term oscillations and restricting amplitude within set limits. This novel approach offers a promising solution for suppressing both first-order resonance and self-excited vibrations in flexible rotor systems, thereby enhancing overall system performance and stability.","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"33 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665648","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 : 2024-11-08DOI: 10.1016/j.ymssp.2024.112004
Jiaqin Zhang, Houfan Du, Suo Wang, Shuzhe Zhou, Wenbo Lyu, Huirong Zhang, Shengxi Zhou
Harvesting mechanical energy from traffic environments is an effective way to power low-power wireless sensors. In this paper, a compact mechanical energy harvester (MEH) is designed for common traffic scenarios, converting reciprocating vertical vibrations into unidirectional rotational motion of a generator through the use of two one-way clutches integrated within bevel gears. A nonlinear coupling model is established to analyze the MEH during its engagement and disengagement phases. This paper focuses on the dynamic characteristics under different load conditions and the safety implications of integrating the MEH into railway operations. Laboratory tests are conducted to evaluate the effects of different harmonic excitations on input force, angular velocity, and output voltage, validating the dynamics model and assessing its performance. Experimental results demonstrate that the MEH can achieve an average power of 42.73 W and a peak power of 96.05 W under harmonic excitation. In simulated scenarios, the peak powers that can be obtained in the freight railway scenario and road sidewalk scenario are 44.3 W and 4.92 W, respectively. These findings demonstrate the significant potential of the proposed MEH for powering electronic devices in traffic settings.
{"title":"A compact mechanical energy harvester for multi-scenario applications in smart transportation","authors":"Jiaqin Zhang, Houfan Du, Suo Wang, Shuzhe Zhou, Wenbo Lyu, Huirong Zhang, Shengxi Zhou","doi":"10.1016/j.ymssp.2024.112004","DOIUrl":"https://doi.org/10.1016/j.ymssp.2024.112004","url":null,"abstract":"Harvesting mechanical energy from traffic environments is an effective way to power low-power wireless sensors. In this paper, a compact mechanical energy harvester (MEH) is designed for common traffic scenarios, converting reciprocating vertical vibrations into unidirectional rotational motion of a generator through the use of two one-way clutches integrated within bevel gears. A nonlinear coupling model is established to analyze the MEH during its engagement and disengagement phases. This paper focuses on the dynamic characteristics under different load conditions and the safety implications of integrating the MEH into railway operations. Laboratory tests are conducted to evaluate the effects of different harmonic excitations on input force, angular velocity, and output voltage, validating the dynamics model and assessing its performance. Experimental results demonstrate that the MEH can achieve an average power of 42.73 W and a peak power of 96.05 W under harmonic excitation. In simulated scenarios, the peak powers that can be obtained in the freight railway scenario and road sidewalk scenario are 44.3 W and 4.92 W, respectively. These findings demonstrate the significant potential of the proposed MEH for powering electronic devices in traffic settings.","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"13 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665652","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 : 2024-11-08DOI: 10.1016/j.ymssp.2024.112076
Kang Yang, Chao Zhang, Hanbo Yang, Linyuan Wang, Nam H. Kim, Joel B. Harley
Autoencoder reconstruction-based unsupervised damage detection is widely utilized in structural health monitoring. However, such methods typically necessitate a comprehensive collection of historical guided waves as training data. Acquiring such data presents challenges, as it requires prolonged monitoring to cover various environmental and operational conditions (EOCs), making these methods less practical for real-world applications. This paper proposes an unsupervised damage detection method solely trained on the current measurements directly. To improve the performance of the unsupervised damage detection method when the training data (the current measurements ) contains a large ratio of damage-induced guided waves, two noise-augmentation strategies are designed to limit the neural network’s learning ability to recover damage-induced guided waves from their segments, improving detection performance. Additionally, we use t-SNE to visualize the impact of noise augmentation on the separation of different types of guided waves within the recovery network’s latent space. Experimental results indicate that input signals with relatively low SNR can achieve better damage detection performance, and a strategy for estimating the optimal noise intensity in input signals is provided in this paper. The effectiveness of the unsupervised this damage detection method with noise-augmentation strategy is validated by 10 regions of 80-days guided waves collected from uncontrolled and dynamic environmental conditions.
{"title":"Improving unsupervised long-term damage detection in an uncontrolled environment through noise-augmentation strategy","authors":"Kang Yang, Chao Zhang, Hanbo Yang, Linyuan Wang, Nam H. Kim, Joel B. Harley","doi":"10.1016/j.ymssp.2024.112076","DOIUrl":"https://doi.org/10.1016/j.ymssp.2024.112076","url":null,"abstract":"Autoencoder reconstruction-based unsupervised damage detection is widely utilized in structural health monitoring. However, such methods typically necessitate a comprehensive collection of historical guided waves as training data. Acquiring such data presents challenges, as it requires prolonged monitoring to cover various environmental and operational conditions (EOCs), making these methods less practical for real-world applications. This paper proposes an unsupervised damage detection method solely trained on the current measurements directly. To improve the performance of the unsupervised damage detection method when the training data (the current measurements ) contains a large ratio of damage-induced guided waves, two noise-augmentation strategies are designed to limit the neural network’s learning ability to recover damage-induced guided waves from their segments, improving detection performance. Additionally, we use t-SNE to visualize the impact of noise augmentation on the separation of different types of guided waves within the recovery network’s latent space. Experimental results indicate that input signals with relatively low SNR can achieve better damage detection performance, and a strategy for estimating the optimal noise intensity in input signals is provided in this paper. The effectiveness of the unsupervised this damage detection method with noise-augmentation strategy is validated by 10 regions of 80-days guided waves collected from uncontrolled and dynamic environmental conditions.","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"250 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665650","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 : 2024-11-08DOI: 10.1016/j.ymssp.2024.112107
Yu-Zu Li, Sheng-En Fang
To improve the mode decomposition capacity of the empirical Fourier transform for time-varying structures, an empirical multi-synchroextracting decomposition method has been proposed and applied to mode analysis of time-varying structures. The multi-synchroextracting transform is introduced to obtain the time–frequency coefficients and the time–frequency spectra of response signals. Then, the time–frequency energy of an arbitrary frequency line is obtained by summing the time–frequency coefficients along the entire time history. Due to the total time–frequency energy within the characteristic frequency band is larger than the energy within an adjacent region outside the frequency band, an energy segmentation operator is constructed to determine the energy spectrum boundaries for each mono-component signal. Once the boundaries are found, a zero-phase filter bank and the Fourier transform are used to accomplish frequency spectrum segmentation of the mono-component signal. Finally, each mono-component signal is reconstructed by employing the inverse Fourier transform to each segment, which realizes the mode decomposition of a time-varying structure. The feasibility of the proposed method has been verified against a numerical 2DOF mass-spring-damper system, a numerical three-story frame structure and an experimental twelve-story reinforced concrete frame structure. The analysis results show that the proposed method provides better precision than the empirical Fourier transform in the aspect of time-varying mode decomposition. Moreover, the proposed method has higher decomposition accuracy in the presence of high interference between adjacent frequency bands.
{"title":"A vibration signal decomposition method for time-varying structures using empirical multi-synchroextracting decomposition","authors":"Yu-Zu Li, Sheng-En Fang","doi":"10.1016/j.ymssp.2024.112107","DOIUrl":"https://doi.org/10.1016/j.ymssp.2024.112107","url":null,"abstract":"To improve the mode decomposition capacity of the empirical Fourier transform for time-varying structures, an empirical multi-synchroextracting decomposition method has been proposed and applied to mode analysis of time-varying structures. The multi-synchroextracting transform is introduced to obtain the time–frequency coefficients and the time–frequency spectra of response signals. Then, the time–frequency energy of an arbitrary frequency line is obtained by summing the time–frequency coefficients along the entire time history. Due to the total time–frequency energy within the characteristic frequency band is larger than the energy within an adjacent region outside the frequency band, an energy segmentation operator is constructed to determine the energy spectrum boundaries for each mono-component signal. Once the boundaries are found, a zero-phase filter bank and the Fourier transform are used to accomplish frequency spectrum segmentation of the mono-component signal. Finally, each mono-component signal is reconstructed by employing the inverse Fourier transform to each segment, which realizes the mode decomposition of a time-varying structure. The feasibility of the proposed method has been verified against a numerical 2DOF mass-spring-damper system, a numerical three-story frame structure and an experimental twelve-story reinforced concrete frame structure. The analysis results show that the proposed method provides better precision than the empirical Fourier transform in the aspect of time-varying mode decomposition. Moreover, the proposed method has higher decomposition accuracy in the presence of high interference between adjacent frequency bands.","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"18 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665649","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 : 2024-11-07DOI: 10.1016/j.ymssp.2024.112094
Angelo Aloisio, Dag Pasquale Pasca, Blaž Kurent, Roberto Tomasi
This paper presents the continuous monitoring of an eight-story cross-laminated timber (CLT) building. The monitoring process includes daily acceleration measurements at the rooftop, along with external temperature, humidity, and wind velocity data. Additionally, moisture content (MC) of timber at various locations in the internal and perimeter walls is measured. The extraction of modal parameters is automated and is based on the Stochastic Subspace Identification method. This research primarily evaluates how environmental factors, particularly temperature, wood MC, snow height, and wind velocity, affect the building’s modal parameters and vibrational response. The data has been found to significantly correlate with temperature, wood MC, and snow level. Subsequently, the authors performed a Bayesian model updating of the building to estimate the relationship between the shear modulus of CLT and the MC. This analysis has led to an empirical formula for predicting the stiffness properties of CLT walls based on wood MC derived from long-term monitoring of a timber building. To the authors’ knowledge, it is the first empirical expression relating a mechanical property of timber and MC, indirectly estimated from ambient vibration data.
本文介绍了对一座八层交叉层压木材（CLT）建筑的连续监测。监测过程包括每天在屋顶测量加速度，以及外部温度、湿度和风速数据。此外，还测量了内墙和外墙不同位置的木材含水率（MC）。模态参数的提取是基于随机子空间识别方法自动进行的。这项研究主要评估环境因素，尤其是温度、木材 MC、雪高和风速如何影响建筑物的模态参数和振动响应。研究发现，数据与温度、木材 MC 和积雪高度密切相关。随后，作者对建筑物进行了贝叶斯模型更新，以估算 CLT 的剪切模量与 MC 之间的关系。这一分析得出了一个经验公式，可根据对木结构建筑的长期监测得出的木材 MC 预测 CLT 墙体的刚度特性。据作者所知，这是首个通过环境振动数据间接估算出的木材机械性能与 MC 之间关系的经验表达式。
{"title":"Long-term continuous dynamic monitoring of an eight-story CLT building","authors":"Angelo Aloisio, Dag Pasquale Pasca, Blaž Kurent, Roberto Tomasi","doi":"10.1016/j.ymssp.2024.112094","DOIUrl":"https://doi.org/10.1016/j.ymssp.2024.112094","url":null,"abstract":"This paper presents the continuous monitoring of an eight-story cross-laminated timber (CLT) building. The monitoring process includes daily acceleration measurements at the rooftop, along with external temperature, humidity, and wind velocity data. Additionally, moisture content (MC) of timber at various locations in the internal and perimeter walls is measured. The extraction of modal parameters is automated and is based on the Stochastic Subspace Identification method. This research primarily evaluates how environmental factors, particularly temperature, wood MC, snow height, and wind velocity, affect the building’s modal parameters and vibrational response. The data has been found to significantly correlate with temperature, wood MC, and snow level. Subsequently, the authors performed a Bayesian model updating of the building to estimate the relationship between the shear modulus of CLT and the MC. This analysis has led to an empirical formula for predicting the stiffness properties of CLT walls based on wood MC derived from long-term monitoring of a timber building. To the authors’ knowledge, it is the first empirical expression relating a mechanical property of timber and MC, indirectly estimated from ambient vibration data.","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"64 1","pages":""},"PeriodicalIF":8.4,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142665653","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 : 2024-11-07DOI: 10.1016/j.ymssp.2024.112115
Reza Teimouri, Marcin Grabowski
Ultrasonic assisted high-speed machining (UAHSM) can be served as a thermomechanical surface sever plastic deformation (SSPD), because of the high-frequency impact load exerting to the sample together with thermomechanical loads due to shearing and plowing. Despite existing of few works which studied the impact of ultrasonic vibration on fatigue life assessment of difficult-to-cut material by experimental approach, they couldn’t provide an in-depth analysis to identify the underlying mechanisms of fatigue due time-consuming and costly fatigue life tests. Hence, elucidating the role of ultrasonic vibration in UAHSM on variation of fatigue life needs further studies. In order to do so, in the present work, a hybrid predictive approach based using ANFIS-based machine learning model and micromechanical Navaro-Rios (NR) fatigue crack propagation model has been introduced to directly correlates the UAHSM’s parameters to fatigue life. Here the former correlates feed rate, cutting velocity and vibration amplitude as process inputs, to surface integrity aspects (SIA) viz residual stress, roughness and grain size as output. Then, the modeled SIA are correlated to fatigue life using the former. The introduced hybrid model was then verified through series of UAHSM by examining the fatigue lives of milled Inconel 718 using four-point bending fatigue tests. Upon confirmation of the developed model, a comprehensive study was carried out to find how the process factors impact variation of SIA and subsequently fatigue. It was found from the results of developed models and confirmatory experiments that the role of ultrasonic vibration on improved fatigue life is mainly due to inducing compressive residual stress and more refined microstructure than the roughness.
超声波辅助高速加工（UAHSM）可作为一种热机械表面断裂塑性变形（SSPD），因为它对试样施加了高频冲击载荷以及剪切和犁耕产生的热机械载荷。尽管已有少数研究通过实验方法研究了超声波振动对难切割材料疲劳寿命评估的影响，但由于疲劳寿命测试耗时且成本高昂，这些研究无法提供深入分析以确定疲劳的内在机制。因此，阐明超声振动在 UAHSM 中对疲劳寿命变化的作用还需要进一步研究。为此，本研究采用基于 ANFIS 的机器学习模型和微机械纳瓦罗-里奥斯（NR）疲劳裂纹扩展模型的混合预测方法，直接将 UAHSM 的参数与疲劳寿命相关联。前者将进给率、切削速度和振动振幅作为工艺输入，将表面完整性（SIA），即残余应力、粗糙度和晶粒度作为输出。然后，利用前者将建模的 SIA 与疲劳寿命相关联。然后，通过一系列 UAHSM，利用四点弯曲疲劳试验对铣削过的 Inconel 718 的疲劳寿命进行检验，从而验证了所引入的混合模型。在确认所开发的模型后，又进行了一项综合研究，以了解工艺因素如何影响 SIA 的变化以及随后的疲劳。从开发的模型和确认实验的结果中发现，超声波振动对提高疲劳寿命的作用主要是诱导压缩残余应力和更精细的微观结构，而不是粗糙度。
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