Mechanical Systems and Signal Processing最新文献

{"title":"A health monitoring and early fault detection method of rotating machines based on latent variables of diffusion model","authors":"Wenyang Hu,&nbsp;Qi Li,&nbsp;Tianyang Wang,&nbsp;Fulei Chu","doi":"10.1016/j.ymssp.2025.113122","DOIUrl":"10.1016/j.ymssp.2025.113122","url":null,"abstract":"<div><div>Deep generative models have gained prominence in the intelligent condition monitoring of rotating machines, primarily utilizing reconstruction errors as health indicators (HIs) to represent actual health conditions. This approach to constructions of HIs significantly influences the robustness and effectiveness of health monitoring and early fault detection. The incorporation of latent variables (LVs) is posited to alleviate these challenges. Nonetheless, the limited modeling capabilities of existing deep generative models constrain their ability to capture intricate patterns. In response, this paper introduces a novel health monitoring and fault prediction methodology leveraging the latent variables derived from diffusion models. A network architecture based on a multi-head self-attention mechanism (MHSA) is designed to effectively map time series monitoring data into the latent space. The diffusion model is initially trained using healthy monitoring samples. Subsequently, for each monitoring sample frame, the distributional differences in the latent space between the monitoring and healthy samples are analyzed to construct the HIs. A comprehensive quantitative and qualitative comparison of our proposed method is conducted against baseline models across multiple scenarios. The results underscore the superior robustness and effectiveness of our approach in the condition monitoring and fault prediction of rotating machines.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"237 ","pages":"Article 113122"},"PeriodicalIF":7.9,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670451","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}

{"title":"Finite element-based numerical modeling and field data analysis of vibration wavefield propagation in urban rail transit facilities","authors":"Lingbin Mo ,&nbsp;Jing Zheng ,&nbsp;Jiajia Meng ,&nbsp;Xiangming Liu","doi":"10.1016/j.ymssp.2025.113086","DOIUrl":"10.1016/j.ymssp.2025.113086","url":null,"abstract":"<div><div>With the rapid expansion of urban rail transit systems, vibrations induced by underground metro operations have become an increasing concern in densely populated environments. This study proposes a method that combines analytical derivation of the excitation source function with finite element modeling to simulate the full-path propagation of metro-induced ground vibrations and validate the results. Departing from conventional 3D FEM-based methods, our approach models the moving train as a sequence of excitation point sources and focuses on wavefield generation, propagation, and attenuation. The source function is derived analytically and implemented within a finite element framework to model elastic wave propagation. Simulation results are compared with field measurements, demonstrating good agreement in terms of energy distribution and attenuation trends. Finally, the study discusses the model’s limitations and outlines future directions for improving its fidelity and applicability.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"237 ","pages":"Article 113086"},"PeriodicalIF":7.9,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670449","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}

{"title":"Generation of spectrum and energy-compatible (SEC) bi-directional ground motions via complex-valued wavelet transform","authors":"Jian Zhou ,&nbsp;Peng Wang ,&nbsp;Jian-Ting Zhou ,&nbsp;Wei Guo ,&nbsp;Akira Igarashi","doi":"10.1016/j.ymssp.2025.113124","DOIUrl":"10.1016/j.ymssp.2025.113124","url":null,"abstract":"<div><div>Modern seismic design codes mandate the simultaneous input of horizontal bi-directional ground motions in nonlinear time history analysis (NLTHA) to ensure comprehensive seismic assessments. This requirement highlights the critical importance of generating bi-directional ground motions that are compatible with the target maximum-direction spectrum (RotD100). However, accurate seismic response evaluations significantly depend on the selection of appropriate seismic inputs. For instance, the Arias intensity build-up process <em>I_a</em>(<em>t</em>), which quantifies the energy content of an accelerogram, has attracted increasing attention in performance-based seismic design. Consequently, it is necessary to propose a method capable of generating RotD100 response spectrum and energy-compatible (SEC) bi-directional ground motions. A novel approach is introduced to address this challenge, leveraging complex-valued wavelets derived from the impulse response of an under critically-damped oscillator. In contrast with previous methods that achieved RotD100 response spectral compatibility by separately manipulating two orthogonal components of bi-directional ground motions, the proposed complex-valued continuous wavelet transform (CWT) method represents the two horizontal components as the real and imaginary parts of complex numbers. The efficacy of the proposed algorithm is validated through the generation of SEC bi-directional ground motions using 40 pairs of seed records for two target RotD100 response spectra. Results suggest that, with the proposed algorithm, the modified bi-directional ground motions closely align with the target RotD100 response spectra and the <em>I_a</em>(<em>t</em>) build-up process mirrors that of the scaled records. Furthermore, the key attributes of the seed records, such as component-level spectral variability, nonlinear time history trace characteristics, and period-dependent polarity, are largely preserved. Additionally, the iterative modification of the <em>I_a</em>(<em>t</em>) build-up process leads to the improved displacement time history compared with the real-valued CWT-based method proposed by Montejo.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"237 ","pages":"Article 113124"},"PeriodicalIF":7.9,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670452","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}

{"title":"Energy harvesting effectiveness of an active horizontal seat suspension under random vibration of varying intensity","authors":"Igor Maciejewski ,&nbsp;Sebastian Pecolt ,&nbsp;Andrzej Blazejewski ,&nbsp;Bartosz Jereczek ,&nbsp;Sebastian Glowinski ,&nbsp;Tomasz Krzyzynski","doi":"10.1016/j.ymssp.2025.113000","DOIUrl":"10.1016/j.ymssp.2025.113000","url":null,"abstract":"<div><div>This study explores the energy harvesting potential of an active horizontal seat suspension system subjected to random vibrations of varying intensity. By integrating a Permanent Magnet Synchronous Motor (PMSM), traditionally used for vibration control, into the suspension system, the research demonstrates how mechanical energy generated during braking can be converted into electrical energy through electromagnetic induction. The proposed system employs a Field-Oriented Control (FOC) strategy with programmable servo-drives to achieve efficient torque control and energy recovery. Experimental and simulation analyses were conducted to evaluate key parameters, including braking torque, energy conversion efficiency, and system integration under vibrational loading. Results indicate that active and regenerative suspension systems outperform passive counterparts in terms of vibration transmissibility and ride comfort. Furthermore, regenerative suspensions provide the added advantage of energy harvesting without compromising stability. Limitations related to input amplitude and force saturation were identified, highlighting design considerations for future applications. This dual-functionality system represents a step forward in vibration control and energy efficiency for vehicle and machinery applications.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"237 ","pages":"Article 113000"},"PeriodicalIF":7.9,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144665480","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}

{"title":"Design of a new type of high-speed scanning galvanometer structure and scanning control strategy","authors":"Lin Wang,&nbsp;Jingjie Wang,&nbsp;Shijiao Liu,&nbsp;Anlin Li,&nbsp;Haonan Sun,&nbsp;Xuelian Liu,&nbsp;Chunyang Wang","doi":"10.1016/j.ymssp.2025.113058","DOIUrl":"10.1016/j.ymssp.2025.113058","url":null,"abstract":"<div><div>Traditional galvanometers usually use optical sensors to achieve superior position accuracy. Due to the drawbacks of poor anti-interference characteristic and their poor accuracy at high temperature and during vibration, the anti-interference characteristic and high-precision positioning characteristic of galvanometers are limited. This paper proposes a new mechanical structure based on differential eddy current sensors. High-performance motion control is the core requirement of galvanometers, but there are uncertainties and nonlinear factors in motion-control systems that restrict the improvement in their performance. This study uses fractional order theory and active disturbance rejection controller to achieve high-speed motion-control strategy. The new type of scanning galvanometer is designed as the experimental platform to test the proposed strategy. The anti-interference characteristic of the vibrating galvanometer is tested under high temperature and vibration conditions. Build the fast circumferential scanning detection system experimental platform, using the high-speed swing of the scanning galvanometer to achieve compensated imaging. When the horizontal turntable speed is set at 210°/s and the scanning galvanometer speed is 516 degrees °/s, the 80 Hz frame rate can be achieved, maintaining a uniform linear range of 5 ms, and the system imaging is clear. The study verifies the performance improvement of the proposed strategy and method in terms of disturbance rejection.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"237 ","pages":"Article 113058"},"PeriodicalIF":7.9,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662745","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}

{"title":"Decoupling and precise imaging of multiple microcracks smaller than 1 mm","authors":"Xiangyan Ding ,&nbsp;Saikun Yu ,&nbsp;Lu Wang ,&nbsp;Caibin Xu ,&nbsp;Bo Yang ,&nbsp;Ning Hu ,&nbsp;Mingxi Deng ,&nbsp;Youxuan Zhao ,&nbsp;Xiaoyang Bi ,&nbsp;Lijin Cheng ,&nbsp;Jishuo Wang ,&nbsp;Jungil Song ,&nbsp;Denvid Lau","doi":"10.1016/j.ymssp.2025.113099","DOIUrl":"10.1016/j.ymssp.2025.113099","url":null,"abstract":"<div><div>The detection of microcracks and decoupling of multiple cracks are crucial for ensuring the safe operation of equipment. Unfortunately, microcracks below 1 mm scale cannot be accurately imaged yet, and decoupling multiple microcracks is even more difficult. Therefore, a nonlinear phased array based on second harmonic was developed for imaging of multiple micro-cracks by experiments and numerical simulation with Total focus method (TFM) by Full Matrix Capture (FMC), the innovation of which is to evaluate the microcrack with small size by low frequency. The nonlinear ultrasonic phased array imaged experimentally successfully a facilitate micro-crack with 0.47 mm measured by the optical microscope. Furthermore, the numerical investigation on the mechanism of nonlinear phased array found that micro-cracks could generate the second harmonic, which follows the superposition principle and can be used for imaging micro-cracks. The minimum identification accuracy of nonlinear ultrasonic phased array was 0.04 mm for 1 MHz fundamental frequency. It overcomes the detection size limitation of linear ultrasonic array with the same fundamental frequency, which is half of the wavelength of fundamental wave as 3.063 mm. In addition, the spatial recognition of double micro-cracks in the horizontal and vertical direction were obtained by 10.00 mm and 5.00 mm, respectively. The nonlinear ultrasonic phased array shows high detection accuracy for multiple micro-cracks, which provides an experimental and theoretical basis for early damage detection and additive manufacturing defects imaging.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"237 ","pages":"Article 113099"},"PeriodicalIF":7.9,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662746","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}

{"title":"Surrogate-aided Bayesian calibration with adaptive learning strategies","authors":"Alexandros A. Taflanidis ,&nbsp;B.S. Aakash ,&nbsp;Sang-ri Yi ,&nbsp;Joel P. Conte","doi":"10.1016/j.ymssp.2025.113014","DOIUrl":"10.1016/j.ymssp.2025.113014","url":null,"abstract":"<div><div>Bayesian inference or calibration for engineering systems requires sampling from the posterior distribution of the system model parameters. For applications with complex numerical models, the computational burden for this sampling, requiring a large number of calls to that model, can be prohibitive. For alleviating this burden, this work investigates an adaptive surrogate model implementation for approximating the numerical model predictions within the process of the Bayesian inference. Gaussian Process (GP) regression is adopted as surrogate modelling technique, while the formulation is embedded within a sequential Monte Carlo (MC) approach, using a series of intermediate auxiliary densities to efficiently derive samples from the posterior target density. The adaptive training of the GP is established by iteratively adding training points to inform the target posterior density approximation. At each iteration, a GP model is constructed using the current set of training points to approximate the system response and, consequently, the posterior distribution. This approximation is then used to facilitate sampling from the posterior. The iterative procedure terminates once the posterior density approximations from successive iterations exhibit sufficient similarity. Convergence is assessed using a combination of criteria, including the stability of the most probable parameter estimates and the similarity of the approximated posterior densities. If convergence is not established, the surrogate model is refined through an adaptive design of computer experiments (DoE) that uses the weighted integrated mean squared error as acquisition function. Through proper selection of the weights, exploitation and exploration strategies are promoted to improve, respectively, efficiency and robustness for the GP approximation. This weight selection combines information from both the target posterior density and the intermediate, auxiliary densities. Strategies are examined for improving computational efficiency for the DoE optimization and for the sequential Monte Carlo sampling once the surrogate model has been updated. Three illustrative examples are examined, considering both static and dynamic Bayesian calibration problems. Results demonstrate the computational efficiency offered through the adaptive GP formulation and provide insights for the best adaptation strategies and for the appropriate selection of response quantities to be adopted as outputs within the GP implementation.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"237 ","pages":"Article 113014"},"PeriodicalIF":7.9,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662743","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}

{"title":"Learnable wavelet-driven physically interpretable networks for bearing fault diagnosis under variable speed","authors":"Yi Qin ,&nbsp;Lijuan Zhao ,&nbsp;Yuejian Chen ,&nbsp;Dengyu Xiao ,&nbsp;Yongfang Mao","doi":"10.1016/j.ymssp.2025.113121","DOIUrl":"10.1016/j.ymssp.2025.113121","url":null,"abstract":"<div><div>Variable speed conditions pose great challenges for intelligent bearing fault diagnosis. The popular intelligent fault diagnosis models neglect the effect of rotational speed when extracting features, meantime the extracted features lack the physical meaning. To this end, a learnable wavelet-driven physically interpretable (LWPI) network is proposed for diagnosing bearing faults under variable speed. Firstly, an entropy-based local peak search (LPS) algorithm with an adaptive instantaneous frequency (IF) search range is designed to extract the rotational frequency ridge from vibration signals, and it can effectively suppress the noise and adjacent interference components. Based on the extracted rotational speed information, a learnable multi-wavelet filter layer is constructed to guide the model in adaptively mining features with physical meaning. Next, a convolution block is constructed to mine the high-dimensional features, followed by a linear dense layer designed for fault classification. Experiments on bearing fault diagnosis under variable speed conditions demonstrate that the proposed LWPI network consistently outperforms five advanced methods. Meanwhile, the efficacy of the entropy-based LPS algorithm and learnable multi-wavelet filter layer are respectively verified by the ablation experiments.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"237 ","pages":"Article 113121"},"PeriodicalIF":7.9,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662744","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}

{"title":"Residual vibration suppression of cooperative robot based on optimization surrogate model and input shaper control","authors":"Tianzuo Niu ,&nbsp;Rong Hu ,&nbsp;Shengen Wu ,&nbsp;Xiao-Jin Wan ,&nbsp;Tianshu Liu","doi":"10.1016/j.ymssp.2025.113120","DOIUrl":"10.1016/j.ymssp.2025.113120","url":null,"abstract":"<div><div>Under high-precision assembly conditions, it is necessary to consider the modal behavior of industrial robots. However, the modal characteristics of complex systems such as industrial robots are highly nonlinear, which means that it is usually cumbersome to evaluate these characteristics by mechanical experiments and finite element methods (FEM). A new Kriging, Bayesian variable selection technique &amp; Domain Adaptation (KRG-BVS-DA) surrogate model optimized by transfer learning domain adaptation is proposed to obtain a natural frequency model of arbitrary pose of an industrial robot. Firstly, the Latin Hypercube sampling (LHS) technique was used to generate 100 reliable training data sets for the surrogate model. Then, seven surrogate models with different optimization algorithms were evaluated to determine the optimal model for predicting the natural frequency. The KRG-BVS-DA surrogate model, optimized via transfer learning and domain adaptation, achieves the highest prediction accuracy of 0.969. In addition, the accuracy of the KRG-BVS-DA surrogate model under different numbers of training samples and the robustness of the KRG-BVS-DA surrogate model for the prediction effect of each order of natural frequency were studied. The prediction data set of KRG-BVS-DA prediction model was iteratively updated by adaptive weighting, and it was found that the prediction accuracy was the highest when iterated once, reaching 0.9728. However, as the number of iterations increased, the prediction accuracy gradually declined, leading to algorithm termination after three iterations. Furthermore, a gravity compensation-based controller was developed, and a simulation model of the robot’s residual vibration suppression control system was established. Through residual vibration analysis of three flexible joints, the effectiveness of the gravity compensation controller in achieving closed-loop control was demonstrated. An improved control scheme combining a negative input shaper with the gravity compensation controller was proposed. Simulation results show that the improved scheme has enhanced the suppression capability of the maximum amplitude by 81.32% and reduced the response delay by 14.03%, achieving better residual vibration suppression effects.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"237 ","pages":"Article 113120"},"PeriodicalIF":7.9,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144656992","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}

{"title":"Autonomous ultrasonic imaging and crack localisation in concrete beams during the fracture process","authors":"Magdalena Rucka ,&nbsp;Monika Zielińska","doi":"10.1016/j.ymssp.2025.113105","DOIUrl":"10.1016/j.ymssp.2025.113105","url":null,"abstract":"<div><div>Monitoring the fracture process in concrete and detecting cracks at an early stage remains one of the major challenges in non-destructive testing of civil engineering structures. This paper presents a novel methodology for real-time fracture imaging in concrete structures using ultrasonic waves. The proposed approach introduces an innovative damage index that enables precise identification of both the location and onset time of crack initiation. Integrated with ultrasonic transmission tomography, this method forms the basis of an automated structural health monitoring system. To thoroughly assess the method performance, experimental validation was conducted on four concrete beams, three of plain concrete and one reinforced with a steel bar, each representing a distinct damage scenario. The accuracy and effectiveness of ultrasonic fracture imaging were verified using X-ray micro-computed tomography and digital image correlation.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"237 ","pages":"Article 113105"},"PeriodicalIF":7.9,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144657086","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}