Mechanical Systems and Signal Processing最新文献_第2页

Cross-attention time-series multi-feature fusion vision transformer for joint formation monitoring in laser scanning welding 用于激光扫描焊接中焊点成形监测的交叉注意时间序列多特征融合视觉变换器

IF 7.9 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanical Systems and Signal Processing

Pub Date : 2025-03-03 DOI: 10.1016/j.ymssp.2025.112531

Shenghong Yan , Bo Chen , Han Gao , Caiwang Tan , Xiaoguo Song , Guodong Wang

As laser scanning welding technology matures in engineering applications, it is a crucial step in developing diagnostics capable of monitoring weld joint forming and meeting the demands of increasingly structurally complex products. In this work, a unique multivariate time-series dataset encompassing keyhole and molten pool image streams was extracted from the collected visual signals. Keyhole and molten pool were respectively fed into a proposed Transformer-based model with two-branches, which incorporated multi-head self-attention and cross-attention mechanisms. The results show that the optimal architecture achieved an accuracy of 99.3%, which outperforms the previous state-of-the-art image-based models. The optimization and ablation experiments have also verified that the temporal characteristics of signals are one of the significant determining factors for the accuracy of laser scanning welding state recognition. The score maps of attention mechanism during the decision-making process demonstrate that the proposed model is able to accurately learn the time-series characteristics of keyhole and molten pool visual signals, exhibiting exceptional capability in effectively capturing fine-grained details of highly dynamic objects from visual signals under varying welding states. In summary, its excellent performance and visualization of the attention mechanism make it a promising diagnostic functional module as a novel strategy for laser scanning welded Joint formation monitoring.

随着激光扫描焊接技术在工程应用中的不断成熟，开发能够监测焊点成型的诊断技术，满足结构日益复杂的产品的需求，是至关重要的一步。在这项工作中，我们从收集到的视觉信号中提取了一个独特的多变量时间序列数据集，其中包括钥匙孔和熔池图像流。钥匙孔和熔池分别被输入到一个基于变压器的双分支模型中，该模型包含多头自注意和交叉注意机制。结果表明，最优架构的准确率达到了 99.3%，优于之前最先进的基于图像的模型。优化和烧蚀实验还验证了信号的时间特性是激光扫描焊接状态识别准确性的重要决定因素之一。决策过程中注意力机制的得分图表明，所提出的模型能够准确学习钥匙孔和熔池视觉信号的时间序列特征，在不同焊接状态下从视觉信号中有效捕捉高动态物体的细粒度细节方面表现出卓越的能力。总之，作为激光扫描焊接接头成形监测的一种新策略，其卓越的性能和关注机制的可视化使其成为一种很有前途的诊断功能模块。

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引用次数: 0

An improved GNSS dynamic monitoring performance evaluation method 改进的全球导航卫星系统动态监测性能评估方法

IF 7.9 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanical Systems and Signal Processing

Pub Date : 2025-03-03 DOI: 10.1016/j.ymssp.2025.112522

Xiaokang Rao , Shengxiang Huang

The dynamic monitoring of buildings based on global navigation satellite system (GNSS) is beneficial in assessing health status and verifying design parameters. Current GNSS dynamic monitoring and evaluation methods still have problems during signal decomposition, such as strong noise interference, mode aliasing and error components generated by over-decomposition or under-decomposition. This paper comprehensively determines the key parameter of variational mode decomposition (VMD) (i.e. decomposition mode number) based on the decomposition components and residuals of VMD and proposes an improved VMD-Hilbert transform (IVMD-HT) GNSS dynamic monitoring performance evaluation method to conduct performance evaluation and feature extraction of GNSS dynamic monitoring. This work demonstrates the feasibility and applicability of the method through simulation and field experiments. The results reveal that the method proposed in this article can achieve the decomposition and noise reduction of GNSS monitoring data effectively. Moreover, the monitoring accuracy of low-cost GNSS receivers combined with this method can be improved by 10 %. Compared with commercial-grade GNSS receivers of different brands, the monitoring accuracy can be improved by 5 %–15 %, which can meet the needs of dynamic monitoring and reach commercial level applications. Furthermore, under the influence of wind-induced environment, the vibration frequency of GNSS dynamic monitoring is mainly between 0 and 0.01 Hz, and the overall impact on buildings is small. The IVMD-HT GNSS dynamic monitoring performance evaluation method can effectively and comprehensively determine the optimal mode number of VMD, achieve signal extraction and noise removal, perform modal analysis and feature extraction, and provide a new processing method for structural performance evaluation and damage detection.

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引用次数: 0

Coexisting attractors, amplitude control, circuit implementation of grid-scroll memristive hyperchaotic oscillator and its application in underwater signal detection 网格滚动记忆超混沌振荡器的共存吸引子、振幅控制、电路实现及其在水下信号探测中的应用

IF 7.9 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanical Systems and Signal Processing

Pub Date : 2025-03-03 DOI: 10.1016/j.ymssp.2025.112525

Yupeng Shen , Zhe Chen , Yaan Li , Weijia Li

Chaotic oscillators play an indispensable role in chaos-based engineering applications. This study proposes a novel grid-scroll memristive hyperchaotic system with infinite equilibrium points and applies it to weak signal detection. First, a novel controllable grid-scroll memristive hyperchaotic system with multi-dimensional extended attractors is designed based on the smooth flux-controlled non-volatile memristor and the piecewise linear function. The system can generate n × n-scroll hyperchaotic attractors in y and z dimensions, with each independent attractor exhibits a similar topological structure. The linear offset switch induced by the piecewise linear function enables the infinite extension of the attractor. Numerical analysis demonstrates that the system has infinitely coexisting single-scroll and multi-scroll attractors, while a built-in parameter enabling global amplitude control is also validated. The analog circuit of the grid-scroll hyperchaotic system is implemented to validate its practical applicability. Then, based on the 2 × 2-scroll hyperchaotic oscillator, combined with the complete empirical mode decomposition with adaptive noise (CEEMDAN) and Hilbert transform, a new underwater acoustic signal detection model is constructed. Compared with the traditional detection models, the designed model not only exhibits higher sensitivity to periodic signals, stronger immunity to various noises, but also easier to distinguish the state changes of the attractor. The experimental results demonstrate that the minimum detection SNR of the detection model can reach −63 dB, and the accuracy of frequency extraction exceeds 99.9 %. The successful detection of ship radiated noise confirms the engineering feasibility of the proposed model.

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引用次数: 0

Design and experimental verification of high frequency elliptical vibration cutting system

IF 7.9 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanical Systems and Signal Processing

Pub Date : 2025-03-03 DOI: 10.1016/j.ymssp.2025.112526

Jianguo Zhang , Cheng Hu , Dongxu Wu , Shanyi Ma , Yunxiang Zheng , Yujiang Lu , Junfeng Xiao , Jianfeng Xu

Mold steel is widely used in optical mold manufacturing precision due to its excellent mechanical properties and chemical stability. However, in the ultra-precision diamond cutting process, the mold steel has tendency to chemically react with the diamond tool, resulting in severe tool wear. Ultrasonic elliptical vibration cutting is an advanced ultra-precision machining technology, while the working frequency of the ultrasonic elliptical vibrator is a major factor restricting the machining efficiency. In this research, a novel high-frequency elliptical vibration cutting system is designed for promoting the machining efficiency. Firstly, based on the longitudinal vibration theory of continuous plasmas, the bending vibration theory of cylindrical rods and finite element simulation analysis, the optimal structure are derived. Subsequently, the performance test shows that the actual working frequency of the system is 110 kHz with vibration amplitudes of 2.5–1 μm_p-p in bending and longitudinal directions. Moreover, the experimental results show that the mirror surface of Sa 3.9 nm can be machined successfully on the mold steel without obvious tool wear. Furthermore, the sinusoidal grid structure was successfully machined on mold steel The performance testing of molded component illustrated the stability and feasibility of the high-frequency elliptical vibration cutting system in cutting microstructural arrays on mold steel.

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引用次数: 0

Design and investigation of a torsional disc-triboelectric nanogenerator with magnetic tristable mechanism

IF 7.9 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanical Systems and Signal Processing

Pub Date : 2025-03-03 DOI: 10.1016/j.ymssp.2025.112515

Dongguo Tan , Xu Ou , Jiaxi Zhou , Kai Wang , Jian Peng , Shijun Yan , Qiang Wang , Hongxin Sun

The torsional vibration widely exists in shafting and human joint motion, however, it is a significant challenge to harvest low-frequency torsional vibration energy over a broad frequency range by utilizing traditional triboelectric nanogenerator (TENG). Herein, a compact torsional disc-triboelectric nanogenerator (TD-TENG) with magnetic tristable mechanism is proposed, which has a low potential barrier and can efficiently convert low-frequency torsional vibration energy into electrical energy over a broad frequency range. The design inspiration of the TD-TENG is introduced firstly and then the working principle is presented. The theoretical model of the TD-TENG is established based on the Newton’s second law of motion and the theory of the TENG. The mechanical and electrical performances of the TD-TENG are obtained by using numerical simulations. The theoretical output voltages are validated by the electrical responses carried out using Simulink circuit model. Subsequently, the influences of the key parameters on the performance of the TD-TENG are studied. The prototype is fabricated and the experiment is conducted to validate the accuracy of the theoretical model of the TD-TENG. Furthermore, the output performance of the TD-TENG under human motion is tested, and the TD-TENG is used to power the LEDs and drive the temperature and humidity sensors under human motion. The results show that the TD-TENG can achieve a maximum output power of 0.64 mW, and its energy-harvesting bandwidth is four times wider than that of the bistable TENG. In addition, the TD-TENG exhibits superior output performance under human motion, capable of powering the LEDs and driving the temperature and humidity sensors, thus holding potential application prospects in the field of human health monitoring.

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引用次数: 0

Churning loss modeling for shroud gears driven by physics-data hybrids

IF 7.9 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanical Systems and Signal Processing

Pub Date : 2025-03-03 DOI: 10.1016/j.ymssp.2025.112532

Xu Qian , Size Yin , Tianyu Sun , Konghua Yang , Sujiao Chen , Yaxu Chu , Yonghua Zhang , Xiaobo Yu , Chunbao Liu

The complexity of multiphase physical mechanisms limits the development of precise mathematical models for churning losses in shrouded gears. This research aims to characterize the impact of shrouds on gear churning losses through a combined data- and physics-driven approach and to develop a mathematical model suitable for complex mechanical systems. Initially, a physical model for churning losses in bare gears was established by simplifying the Navier-Stokes equations, providing a foundation for modeling under shrouded conditions. Subsequently, a mathematical model, the churning loss coefficients model (CLCM), was developed using least squares fitting. This model incorporates seven coefficients to be determined. After numerous tries, the presented CLCM adapts to multiple shroud configurations considering the evolution of the gear speeds. In addition, a data-driven optimization framework for the CLCM was designed. It integrates a backpropagation neural network, optimized by particle swarm optimization, with third-generation non-dominated sorting genetic algorithms. This framework, which integrates the capabilities of accurate description of multiphase physical processes and comprehensive multi-objective search, enables the comprehensive optimization of the primary coefficients in the CLCM across multiple speeds. Finally, the generalization capability of the optimized CLCM was validated on a complex planetary gear system, demonstrating a prediction accuracy exceeding 93 %. These findings provide valuable insights for the development of more efficient gearboxes.

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引用次数: 0

Spectral anomaly detection for identifying prestress loss in prestressed concrete bridges: The PSC-A16 case study

IF 7.9 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanical Systems and Signal Processing

Pub Date : 2025-03-03 DOI: 10.1016/j.ymssp.2025.112506

Giulio Mariniello, Tommaso Pastore, Domenico Asprone, Edoardo Cosenza

The timely identification of damages in prestressed concrete bridges is a significant challenge for the structural health monitoring community, primarily when the malfunctions are related to the prestressing system. Despite extensive research, a shared solution for detecting tension loss in prestressed tendons is still lacking. This paper investigates the capability of Spectral Jump-Anomaly Detection (SJ-AD), a data-driven technique that directly analyzes accelerometric data in the frequency domain and emits alerts within a multi-window implicit thresholding scheme. Additionally, this work introduces the PSC-A16 Benchmark, a case study involving vibration monitoring of an Italian viaduct during strengthening interventions with external tendons, thus providing data at different prestressing levels. Evaluating SJ-AD on the PSC-A16 benchmark, this paper shows that the proposed method can successfully provide alerts related to tension losses that affect the bridge deck.

引用次数: 0

Pulse-echo-based third-order nonlinear ultrasound enhancement and its applications to microstructural characterizations in metal additive manufacturing 基于脉冲回波的三阶非线性超声增强及其在金属增材制造微结构表征中的应用

IF 7.9 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanical Systems and Signal Processing

Pub Date : 2025-03-03 DOI: 10.1016/j.ymssp.2025.112488

Seong-Hyun Park

Second harmonic-based nonlinear ultrasonics is an emerging nondestructive testing technology that has recently gained attention owing to its high sensitivity for characterizing microstructures. However, this technique operates exclusively in the through-transmission mode and cannot be applied using the pulse-echo (PE) method, which is highly suitable for field applications owing to the phase-inversion effect. To address this limitation, we develop a PE-based third-order nonlinear ultrasonic technique for characterizing the microstructures of additive manufacturing (AM) components. Experiments demonstrate that the PE-based third-harmonic technique is highly sensitive to microstructural changes, including micro-oxide inclusions and grain structures formed during AM, whereas the conventional second-harmonic technique is not. An extensive discussion, supported by numerical simulations, is provided to explain these findings. The developed technique shows potential for in-situ monitoring in various industrial fields, including AM, because it enables single-sided measurements.

基于二次谐波的非线性超声技术是一种新兴的无损检测技术，由于其在表征微观结构方面的高灵敏度，最近备受关注。然而，由于相位反转效应，这种技术只能在直通传输模式下运行，无法使用脉冲回波（PE）方法，而这种方法非常适合现场应用。为了解决这一局限性，我们开发了一种基于 PE 的三阶非线性超声波技术，用于表征增材制造（AM）部件的微结构。实验证明，基于聚乙烯的三次谐波技术对微观结构变化（包括 AM 过程中形成的微氧化物夹杂物和晶粒结构）高度敏感，而传统的二次谐波技术则不敏感。为了解释这些发现，我们在数值模拟的支持下进行了广泛的讨论。所开发的技术可进行单面测量，因此具有在包括 AM 在内的各种工业领域进行原位监测的潜力。

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引用次数: 0

Multi-phase adaptive methodology for mitigating environmental and operational variability in slowly changing time-variant engineering structures 减缓缓慢变化的时变工程结构的环境和运行变异性的多阶段适应方法

IF 7.9 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanical Systems and Signal Processing

Pub Date : 2025-03-02 DOI: 10.1016/j.ymssp.2025.112494

Kevin Qu , Alasdair Logan , Euan Miller , David Garcia Cava

This work presents a multi-phase adaptive methodology to mitigate environmental and operational variability (EOV) in slowly changing time-variant engineering structures. By employing stochastic modelling of damage sensitive features (DSF), the approach effectively mitigates EOVs, adapts to structural states, and quantifies uncertainty. A hyperparameter regulates data composition from two proximate, similarly designed structures, capturing EOV-DSF interdependencies across evolving states. The study reveals that long-term monitoring introduces distinct structural phases with similar, but not identical, behaviour, challenging the application of a singular and static model due to the inherent time-variant nature of structure evolution. Applied to an offshore wind turbine undergoing structural integrity evolution, the outcomes underscore the adaptability of the methodology. The results demonstrate that combined data-models can be adjusted to different structural phases over time, yielding more accurate representation compared to traditional methods reliant on static data-models. The multi-phase adaptive methodology proves to be more efficient in delivering less variable and more robust DSFs for the long-term monitoring of slowly changing, time-variant engineering structures.

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引用次数: 0

Nonlinear vibration characteristics and reliability analysis of dynamic model of linear motion platform supported by double rolling linear guide rails

IF 7.9 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanical Systems and Signal Processing

Pub Date : 2025-03-01 DOI: 10.1016/j.ymssp.2025.112507

Jinsong Zhao , Mengtao Xu , Xiaoxuan Gong , Zhiyuan Jiang , Zhenghong Yao , Chunyu Zhao , Yimin Zhang

This paper proposes a 5DOF nonlinear dynamic modeling method for a linear guide platform supported by four carriages, systematically integrating the coupling effects of translational and angular displacements, internal preload, and time-varying excitation into a unified framework. A nonlinear restoring force function is constructed to reveal the complex dynamic behavior induced by contact nonlinearity, including multistability in frequency response, bifurcation phenomena, and the stability regulation of periodic motion. Numerical simulations deeply analyze the effects of excitation frequency and amplitude, preload levels, and platform weight on the system’s dynamic performance, clarifying the significant inhibitory effect of higher preload on aperiodic motion. Larger excitation amplitudes expand the frequency region associated with unstable motion and increase the number of jumping frequency points. Experimental verification confirms the accuracy and broad applicability of the model under complex dynamic conditions. Furthermore, by combining an active learning Kriging model with Monte Carlo simulation, the study quantitatively evaluates the influence of key carriage parameters on platform vibration and reliability, offering a novel strategy for optimizing the design of high-precision linear guide platforms. This research not only addresses gaps in modeling complex coupling effects but also establishes a robust theoretical and engineering foundation for predicting dynamic characteristics and optimizing the design of high-precision mechanical systems.

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引用次数: 0