Mechanical Systems and Signal Processing最新文献

{"title":"Lateral-vertical coupled nonlinear vibration characteristics of HTS maglev based on multiscale method and experimental test","authors":"Haitao Li ,&nbsp;Shan Wang ,&nbsp;Sheng Liu ,&nbsp;Zigang Deng ,&nbsp;Junqi Xu","doi":"10.1016/j.ymssp.2025.113449","DOIUrl":"10.1016/j.ymssp.2025.113449","url":null,"abstract":"<div><div>High-temperature superconducting (HTS) maglev systems provide inherently stable, non-contact levitation and low energy consumption, making them attractive for high-speed transportation applications. However, the nonlinear dependence of levitation and guidance forces with lateral and vertical displacements leads to pronounced lateral-vertical coupling effects. These coupled vibrations, especially under external perturbations, can activate a broad range of resonant frequencies, thereby potentially affecting ride stability and operational safety. In this study, the nonlinear lateral-vertical coupled vibration responses of an HTS maglev system are investigated through integrated theoretical analysis, numerical simulations, and experimental validation. A coupled levitation/guidance force model is established via numerical simulations, quasi-static measurements, and dynamic experiments. The multiscale method is applied to derive analytical solutions for the coupled dynamics, under free vibration, lateral primary resonance, and forced vibration at critical frequencies. Theoretical analysis and numerical simulations reveal that lateral disturbances not only induce significant vertical responses but also excite a rich spectrum of resonant modes, including sum and difference frequencies between the lateral and vertical natural frequencies. These phenomena are confirmed by dedicated forced vibration experiments over a wide frequency range. Comparisons demonstrate strong agreement between theoretical predictions, simulations, and experimental data. Importantly, the study identifies specific frequency regions where the external excitation matches the sum or difference of the system’s natural frequencies, which are critical for system stability and result in substantial amplification of coupled vibration amplitudes. The combined theoretical and experimental framework based on the multiscale method enables accurate prediction of the nonlinear lateral-vertical coupled dynamics in HTS maglev systems and clearly identifies the critical frequency regions that need to be avoided in design and operation. These findings are of great significance for ensuring the stability and safety of HTS maglev systems at high speeds and are essential for maintaining overall system reliability.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"240 ","pages":"Article 113449"},"PeriodicalIF":8.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222363","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":"Nonlinear fault diagnosis and localization of dual rotor-bearing-casing system based on feature parameter identification","authors":"Jiajing Zhang ,&nbsp;Jianping Jing","doi":"10.1016/j.ymssp.2025.113408","DOIUrl":"10.1016/j.ymssp.2025.113408","url":null,"abstract":"<div><div>Considering complex structure of aero-engine rotor systems and the wide variety of faults, fault localization and identification face enormous challenges. According to previous studies, traditional feature extraction fault diagnosis methods are difficult to effectively diagnose and locate faults, and diagnosis methods based on data and artificial intelligence rely on a large amount of fault data, which is difficult to collect considering the actual test conditions of aeroengine. By combining the dynamical model and feature parameters of fault, parameter identification using limited measured sensor data is an effective and practical technique for fault diagnosis. This study proposes a fault diagnosis technique based on fault feature parameters identification using augmented extended Kalman filter (AEKF). A reduced order dynamical finite element model of an aeroengine dual-rotor-casing system is built to improve computational efficiency and a weighted overall iteration technique is employed to accelerate parameter stabilization and convergence. The AEKF is then employed to approach the complexities associated with the nonlinearity of the system model. The accuracy of the finite element model and fault identification method was verified by experiment. A numerical test is furthermore adopted for the aero-engine dual-rotor-casing system and the multiple fault feature parameters are identified, and the fault and location corresponding to each feature parameter are hence identified and localized. The results clearly demonstrate that the method can quickly identify linear and nonlinear faults of the rotor system and maintain the accuracy of fault parameter identification when the fault parameters change.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"240 ","pages":"Article 113408"},"PeriodicalIF":8.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222359","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":"Influence mechanism of multi-bolt-flange-spigot structure on the vibration response of dual-rotor system: Numerical and experimental investigations","authors":"Penghao Zhao ,&nbsp;Fang He ,&nbsp;Jianhua Liu ,&nbsp;Hao Gong ,&nbsp;Zhengyue Tan ,&nbsp;Zhongtian Lu","doi":"10.1016/j.ymssp.2025.113438","DOIUrl":"10.1016/j.ymssp.2025.113438","url":null,"abstract":"<div><div>A resonance-like peak emerges at supercritical speed in dual-rotor system, which will bring a harm to aero-engine. Currently, the mechanism of this abnormal vibration at non-resonant condition remains unclear. In this study, a novel dynamic model of dual-rotor system with a multi-bolt-flange-spigot (BFS) structure is established, incorporating the microscopic contact stiffness and local slippage at interfaces. Based on microscopic contact model and thick-walled cylinder theory, a <em>trans</em>-scale mechanical model of BFS structure is deduced. The microscopic topography and contact pressure of the interfaces at flange and spigot are fully considered. In this way, the lateral and bending stiffness of BFS structure are improved, and the skewness angle of inertial principal is derived to update load excitation vectors. Subsequently, the overall motion equations are obtained and numerically solved. Vibration responses at different speeds are analyzed, including the effects of bolt preloads, interference values of spigot, and surface roughness. Results show that the irreversible local slippage at spigot interface induces the skewness of inertial principal axis, which mainly contributes to the resonance-like peak at supercritical speed. Finally, a dual-rotor test rig is designed to validate the numerical results.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"240 ","pages":"Article 113438"},"PeriodicalIF":8.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222360","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":"Grammar-based ordinary differential equation discovery","authors":"Karin Yu ,&nbsp;Eleni Chatzi ,&nbsp;Georgios Kissas","doi":"10.1016/j.ymssp.2025.113395","DOIUrl":"10.1016/j.ymssp.2025.113395","url":null,"abstract":"<div><div>The understanding and modeling of complex physical phenomena through dynamical systems has historically driven scientific progress, providing essential tools for predicting system behavior under diverse conditions over time. In engineering, the discovery of dynamical systems is indispensable for computational modeling, diagnostics, prognostics, and control of engineered systems. Joining recent efforts that harness the power of symbolic regression in this domain, we propose a novel framework for the end-to-end discovery of ordinary differential equations (ODEs), termed <em>Grammar-based ODE Discovery Engine</em> (GODE). The proposed methodology combines formal grammars with dimensionality reduction and stochastic search for efficiently navigating high-dimensional combinatorial spaces. Grammars serve to inject domain knowledge and provide structure, both constraining and guiding the search for candidate expressions. GODE proves to be more sample- and parameter-efficient than state-of-the-art transformer-based models and to discover more accurate and parsimonious ODE expressions than both genetic programming- and other grammar-based methods, particularly for complex inference tasks, such as the discovery of structural dynamics. Thus, we introduce a tool that could play a catalytic role in dynamics discovery tasks, including modeling, system identification, and monitoring applications.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"240 ","pages":"Article 113395"},"PeriodicalIF":8.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222361","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":"Interference structure-based directional acoustic-band amplifier for enhanced sound sensing","authors":"Semin Ahn ,&nbsp;Sung-Hoon Ahn","doi":"10.1016/j.ymssp.2025.113442","DOIUrl":"10.1016/j.ymssp.2025.113442","url":null,"abstract":"<div><div>Listening to a desired sound from a cacophonous background remains a formidable challenge using a compact, single acoustic sensor. In this study, we developed a novel interference structure with a phase cancellation mechanism for directional bandpass filtering and amplification, dramatically enhancing target sound sensing in heavy-noise environments. The compact design (0.2 <span><math><mi>L</mi></math></span>), a log-scale reduction compared to leading methods, the proposed structure effectively amplifies from 1873 Hz to 22 kHz with an outstanding structural efficiency (21.60). In contrast to traditional acoustic metamaterials that require re-fabrication for tuning, the structure enables target frequency tuning simply by rotating its orientation. Under 100  dB noise, the structure improves the peak magnitude of the target frequency by up to 4.82 times. In fault diagnosis, under 84  dB noise factory, amplifies critical CNC tool features by up to 19.9 times. Notably, a CNC tool fault diagnosis AI model achieved a 78.6 % true positive rate under 84  dB noise using the structure, compared to 0.0 % in the free-field condition. This work offers a new paradigm for compact and high-performance acoustic sensing, combining sensitivity, selectivity, and robustness, with strong potential for deployment in advanced intelligent fault diagnostics in extreme noise environments.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"240 ","pages":"Article 113442"},"PeriodicalIF":8.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222190","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":"Visual vibration measurement using intensity optical flow with optical field correction under uneven illumination","authors":"Xuefen Xiong ,&nbsp;Lei Liu ,&nbsp;Chunzhen Wei ,&nbsp;Sichao Tan ,&nbsp;Mengmeng Dang ,&nbsp;Zhi Zhong ,&nbsp;Bin Liu ,&nbsp;Lei Yu ,&nbsp;Mingguang Shan","doi":"10.1016/j.ymssp.2025.113431","DOIUrl":"10.1016/j.ymssp.2025.113431","url":null,"abstract":"<div><div>The intensity optical flow method is widely used in vibration measurement due to its efficiency and low computational cost. However, its performance degrades significantly under uneven illumination, often resulting in distorted vibration mode shapes in full-field measurements. To address this issue, this study proposes a novel approach that incorporates an optical field correction model into the intensity-based optical flow framework. This is the first method to explicitly model the spatial relationship between illumination and vibration response, enabling one-shot correction of mode shape distortion using single-frame optical field estimation. Simulation results demonstrate that the proposed method achieves Modal Assurance Criterion (MAC) values above 0.95 under various complex lighting conditions and maintains values above 0.85 even in the presence of severe system noise. Compared to conventional dynamic correction techniques, it eliminates cumulative errors and significantly improves processing efficiency by avoiding frame-by-frame adjustments. Experimental validations on metal plates, air compressors, and gold-coated thin films further confirm the robustness and practical applicability of the method in real-world vibration measurement scenarios.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"240 ","pages":"Article 113431"},"PeriodicalIF":8.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222357","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":"Simulation of parameterized random fields, Part II: Non-Gaussian cases","authors":"Zhibao Zheng ,&nbsp;Hongzhe Dai ,&nbsp;Michael Beer ,&nbsp;Udo Nackenhorst","doi":"10.1016/j.ymssp.2025.113386","DOIUrl":"10.1016/j.ymssp.2025.113386","url":null,"abstract":"<div><div>This paper presents two numerical algorithms to simulate non-Gaussian random fields that are parameterized by random parameters. The simulation of such kind of random fields is very challenging due to their parameterized non-Gaussian properties. For each sample realization of the random parameters, the parameterized non-Gaussian random field degrades into a classical non-Gaussian random field. In the first algorithm, we present a sample-based iterative algorithm to simulate the obtained classical non-Gaussian random field. Initial random samples are first generated to meet the sampled marginal distribution, and an iterative procedure is adopted to change the ranking of the random samples to match the target sampled covariance function. However, this method is computationally expensive since we have to simulate a non-Gaussian random field for each sample realization of the random parameters. To avoid this issue, we develop a reformulation-based algorithm in the second method. Parameterized marginal distributions are reformulated as non-parameterized marginal distributions via a conditional probability integral, and parameterized covariance functions are reformulated as non-parameterized covariance functions via an expectation operation on random parameters. In this way, the original parameterized non-Gaussian random field is transformed into a classical non-Gaussian random field. The sample-based iterative algorithm is then used to simulate the obtained non-Gaussian random field. Moreover, a multi-fidelity approach is presented to further reduce the computational effort of the above iteration by taking advantage of the Karhunen-Loève expansion. Specifically, the expanded random variables in Karhunen-Loève expansion are calculated on a low-fidelity model and the deterministic functions in Karhunen-Loève expansion are calculated on a high-fidelity model. Thus, the method has low computational effort and high fidelity simultaneously. Two numerical examples, including one- and three-dimensional parameterized non-Gaussian random fields, are used to verify the effectiveness of the proposed methods.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"240 ","pages":"Article 113386"},"PeriodicalIF":8.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222364","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":"Optimal circumferential cavity allocation methodology for diaphragm labyrinth seals: balancing rotordynamic stability and leakage control","authors":"Xiang Zhang ,&nbsp;Jieyu Zhou ,&nbsp;Runchao Zhao ,&nbsp;Zhitong Li ,&nbsp;Qianlei Gu ,&nbsp;Zongquan Deng ,&nbsp;Yinghou Jiao","doi":"10.1016/j.ymssp.2025.113424","DOIUrl":"10.1016/j.ymssp.2025.113424","url":null,"abstract":"<div><div>This study systematically examines the effect of circumferential diaphragm number on the rotordynamic and leakage performance of diaphragm labyrinth seals (DLS) through transient CFD simulations, experimental validation, and a previously established dimensionless leakage model. Results reveal a critical transition at 16 diaphragms, where the effective damping’s dependence on whirl frequency shifts from positive (fewer than 16) to negative (more than 16). Cavities near the gas inlet consistently contribute higher stiffness and damping, with the stiffness—whirl frequency relationship evolving from monotonic to nonlinear as diaphragm count increases. Both leakage and rotordynamic coefficients tests on the 16 diaphragm DLS confirm the predictive accuracy of the CFD and theoretical models. A general increase is observed in pressure drop from inlet to outlet blades, despite there is minor deviations between even and odd numbered blades in experiments. Design recommendations suggest that no fewer than 16 diaphragms are needed to ensure sufficient rotordynamic stability, particularly to avoid the crossover-frequency-induced instabilities observed in 4 and 8 diaphragms configurations. However, enhanced leakage near the outlet requires tailored structural optimization for effective pressure retention. Overall, the configuration with 32 circumferential diaphragms offers the best balance between leakage suppression and dynamic stability, making it the most favorable design among those investigated.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"240 ","pages":"Article 113424"},"PeriodicalIF":8.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222250","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":"Omnidirectional multi-view high-speed-camera-based full-field 3D modal identification","authors":"Krištof Čufar ,&nbsp;Janko Slavič","doi":"10.1016/j.ymssp.2025.113415","DOIUrl":"10.1016/j.ymssp.2025.113415","url":null,"abstract":"<div><div>Structures with complex geometries often exhibit elaborate spatial responses to a dynamic excitation. Traditional point-wise vibration measurement techniques, such as accelerometer measurements, provide reliable results usually lacking spatial resolution. In contrast, image-based displacement identification methods provide full-field non-contact measurement capabilities at the cost of a lower dynamic range. Furthermore, 3D digital image correlation is able to reconstruct the geometry and spatial displacements of structures, but require multi-camera setups to work. In the case of omnidirectional experimental modal analysis, frequency-domain stitching is required. This research builds on the recently introduced, multi-view, frequency-domain-triangulation method, that provides a framework for the extraction of full-field 3D operating deflection shapes with a high dynamic range. The existing method is based on sequential high-speed recordings of the vibrating structure made from different views; however, to work it requires prior knowledge of the structure’s geometry. In this research, following an initial camera calibration, a 3D surface mesh is extracted using a photogrammetric geometry reconstruction approach. Displacements of the vibrating object are then recorded and extracted from a large number of views and full-field 3D operating deflection shapes are extracted using frequency-domain triangulation. In the final step, the deflection shapes are magnified and mapped to the reconstructed 3D surface mesh to visualize the vibrational behavior of the test subject. The results of the introduced method for the extraction and visualization of full-field 3D deflection shapes do not require any prior knowledge regarding the geometric or dynamic properties of the studied object. The considerable over-determination in the frequency domain of measurement data obtained from the large number of viewpoints leads to a larger dynamic range and a better reconstruction.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"240 ","pages":"Article 113415"},"PeriodicalIF":8.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222365","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":"Analytical study of low-frequency flexural vibration band gaps of lightweight stiffened meta-plates with inertial amplified resonators","authors":"Xunyu Li ,&nbsp;Yong Hu ,&nbsp;Yinggang Li","doi":"10.1016/j.ymssp.2025.113396","DOIUrl":"10.1016/j.ymssp.2025.113396","url":null,"abstract":"<div><div>In this paper, a two-dimensional periodic stiffened <em>meta</em>-plate structure with inertial amplified resonators is proposed to achieve the engineering structure design with lightweight high-strength performance and low-frequency broadband flexural vibration isolation characteristics simultaneously. A theoretical model of periodic stiffened <em>meta</em>-plate with inertial amplified resonators is established, based on the Lagrange equation and the beam-plate coupling theory. The flexural band gap and vibration isolation properties of the periodic stiffened <em>meta</em>-plates are studied by using the plane wave expansion method. Numerical calculation and experimental tests were conducted to verify the proposed theoretical model. Results show that the proposed lightweight high-strength stiffened <em>meta</em>-plate with inertial amplified resonators can significantly enhance the low-frequency broadband flexural bandgap compared to the existing periodic stiffened plate and stiffened <em>meta</em>-plate with local resonators. The performance enhancement mechanism is mainly attributed to the coupling effect of stiffened plate and inertial amplified resonators. The flexural bandgap and low-frequency broadband vibration reduction performance of the proposed lightweight stiffened <em>meta</em>-plates with inertial amplified resonators can be significantly enhanced based on the theoretical model and the multi-objective NSGA-II algorithm.</div></div>","PeriodicalId":51124,"journal":{"name":"Mechanical Systems and Signal Processing","volume":"240 ","pages":"Article 113396"},"PeriodicalIF":8.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145222189","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}