Compressed sensing based on dictionary learning for underdetermined modal identification

2020 ◽  
Vol 64 (1-4) ◽  
pp. 129-136
Author(s):  
Wei Guan ◽  
Longlei Dong ◽  
Jinxiong Zhou
Keyword(s):  
Compressed Sensing ◽  
Dictionary Learning ◽  
Engineering Application ◽  
Modal Identification ◽  
Mode Shapes ◽  
Engineering Structures ◽  
New Approach ◽  
Learned Dictionary ◽  
Complete Measurement ◽  
Practical Engineering

With the engineering structures becoming more complicated, it is difficult to obtain complete measurement responses with limited sensors. Thus, carrying out the underdetermined modal identification will have practical engineering application values. In this paper, a new approach for underdetermined blind modal identification based on dictionary learning in the framework of compressed sensing (CS) is proposed. The principal idea is to estimate modal shapes using a clustering technique, and recover modal responses combing the estimated mode shapes matrix and the learned dictionary. The experiment results on a typical cantilever beam structure illustrate that the proposed method can perform accurate dynamic parameters identification whether in underdetermined case or determined case.

Recent advances in reliability analysis of aeroengine rotor system: a review

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xue-Qin Li ◽  
Lu-Kai Song ◽  
Guang-Chen Bai
Keyword(s):  
Reliability Analysis ◽  
Surrogate Model ◽  
Engineering Application ◽  
Rotor System ◽  
Engineering Structures ◽  
Content Type ◽  
Reliability Design ◽  
Rotor Systems ◽  
Practical Engineering ◽  
Complex Engineering

PurposeTo provide valuable information for scholars to grasp the current situations, hotspots and future development trends of reliability analysis area.Design/methodology/approachIn this paper, recent researches on efficient reliability analysis and applications in complex engineering structures like aeroengine rotor systems are reviewd.FindingsThe recent reliability analysis advances of engineering application in aeroengine rotor system are highlighted, it is worth pointing out that the surrogate model methods hold great efficiency and accuracy advantages in the complex reliability analysis of aeroengine rotor system, since its strong computing power can effectively reduce the analysis time consumption and accelerate the development procedures of aeroengine. Moreover, considering the multi-objective, multi-disciplinary, high-dimensionality and time-varying problems are the common problems in various complex engineering fields, the surrogate model methods and its developed methods also have broad application prospects in the future.Originality/valueFor the strong demand for efficient reliability design technique, this review paper may help to highlights the benefits of reliability analysis methods not only in academia but also in practical engineering application like aeroengine rotor system.

scholarly journals Identification of Mode Shapes Based on Ambient Signals and the IA-VMD Method

2021 ◽  
Vol 11 (2) ◽  
pp. 530
Author(s):  
Fang Liu ◽  
Sisi Lin ◽  
Chonggang Chen ◽  
Kangzhi Liu ◽  
Runmin Zou ◽  
...  
Keyword(s):  
Oscillation Mode ◽  
Engineering Application ◽  
Frequency Domain Analysis ◽  
Power Grids ◽  
Modal Identification ◽  
Normal Operation ◽  
Mode Shapes ◽  
Mode Decomposition ◽  
Interconnected Power Grids ◽  
Prony Algorithm

The paper presents a multiaspect analysis of multivalues and the broadband nature of system oscillation. By analyzing the ambient signal caused by random small disturbances during the normal operation of interconnected power grids, many system operation characteristics can be obtained. The traditional signal processing method cannot extract the information from ambient signals effectively. Aiming at the problem of broadband oscillation mode superposition and the difficulty of extracting information from ambient signals, an iterative adaptive variational mode decomposition (IA-VMD) method is proposed based on frequency domain analysis and signal energy. Additionally, the IA-VMD method, combined with a bandpass filter and the Prony algorithm, is used to realize the modal identification of broadband oscillation and ambient signals. Simulation experiments show that the IA-VMD method has good adaptability, antinoise characteristics, and a certain significant engineering application value as well.

scholarly journals Performance of Camera-Based Vibration Monitoring Systems in Input-Output Modal Identification Using Shaker Excitation

2021 ◽  
Vol 13 (17) ◽  
pp. 3471
Author(s):  
Maksat Kalybek ◽  
Mateusz Bocian ◽  
Wojciech Pakos ◽  
Jacek Grosel ◽  
Nikolaos Nikitas
Keyword(s):  
Image Processing ◽  
Modal Analysis ◽  
Experimental Modal Analysis ◽  
Modal Identification ◽  
Vibration Monitoring ◽  
Mode Shapes ◽  
Monitoring Systems ◽  
Input Output ◽  
Engineering Structures ◽  
Scaled Model

Despite significant advances in the development of high-resolution digital cameras in the last couple of decades, their potential remains largely unexplored in the context of input-output modal identification. However, these remote sensors could greatly improve the efficacy of experimental dynamic characterisation of civil engineering structures. To this end, this study provides early evidence of the applicability of camera-based vibration monitoring systems in classical experimental modal analysis using an electromechanical shaker. A pseudo-random and sine chirp excitation is applied to a scaled model of a cable-stayed bridge at varying levels of intensity. The performance of vibration monitoring systems, consisting of a consumer-grade digital camera and two image processing algorithms, is analysed relative to that of a system based on accelerometry. A full set of modal parameters is considered in this process, including modal frequency, damping, mass and mode shapes. It is shown that the camera-based vibration monitoring systems can provide high accuracy results, although their effective application requires consideration of a number of issues related to the sensitivity, nature of the excitation force, and signal and image processing. Based on these findings, suggestions for best practice are provided to aid in the implementation of camera-based vibration monitoring systems in experimental modal analysis.

scholarly journals A Modal Perturbation Method for Eigenvalue Problem of Non-Proportionally Damped System

2020 ◽  
Vol 10 (1) ◽  
pp. 341
Author(s):  
Danguang Pan ◽  
Xiangqiu Fu ◽  
Qingjun Chen ◽  
Pan Lu ◽  
Jinpeng Tan
Keyword(s):  
Perturbation Method ◽  
State Space ◽  
Mode Shapes ◽  
Vibration Modes ◽  
Algebraic Equations ◽  
Engineering Structures ◽  
Damped System ◽  
Real Mode ◽  
Nonlinear Algebraic Equations ◽  
Practical Engineering

The non-proportionally damped system is very common in practical engineering structures. The dynamic equations for these systems, in which the damping matrices are coupled, are very time consuming to solve. In this paper, a modal perturbation method is proposed, which only requires the first few lower real mode shapes of a corresponding undamped system to obtain the complex mode shapes of non-proportionally damped system. In this method, an equivalent proportionally damped system is constructed by taking the real mode shapes of a corresponding undamped system and then transforming the characteristic equation of state space into a set of nonlinear algebraic equations by using the vibration modes of an equivalent proportionally damped system. Two numerical examples are used to illustrate the validity and accuracy of the proposed modal perturbation method. The numerical results show that: (1) with the increase of vibration modes of the corresponding undamped system, the eigenvalues and eigenvectors monotonically converge to exact solutions; (2) the accuracy of the proposed method is significantly higher than the first-order perturbation method and proportional damping method. The calculation time of the proposed method is shorter than the state space method; (3) the method is particularly suitable for finding a few individual orders of frequency and mode of a system with highly non-proportional damping.

Electrospun nano-bio membrane for bone tissue engineering application- a new approach

2020 ◽  
Vol 249 ◽  
pp. 123010 ◽  
Author(s):  
Senthil Rethinam ◽  
Bahri Basaran ◽  
Sumathi Vijayan ◽  
Ali Mert ◽  
Oğuz Bayraktar ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Engineering Application ◽  
Tissue Engineering Application ◽  
New Approach ◽  
Bone Tissue Engineering Application

Dynamic Characteristics and Stability Analysis of Two-Dimensional (2D) Electro-Hydraulic Proportional Directional Valve

2015 ◽  
Author(s):  
S. Li ◽  
J. Ruan ◽  
B. Meng ◽  
W. A. Jia ◽  
H. Y. Xie
Keyword(s):  
Dynamic Characteristics ◽  
Magnetic Force ◽  
Engineering Application ◽  
Proportional Valve ◽  
Acceptable Range ◽  
Hydrostatic Force ◽  
Practical Engineering ◽  
Direct Operation ◽  
Electrohydraulic Valve ◽  
Proportional Directional Valve

A 2D electrohydraulic proportional directional valve is proposed, which integrates both direct and pilot operation of the valve. In this valve, the output magnetic force of the proportional solenoid is converted to rotate the spool through a thrust-torsion coupling and thus the pressure in the valve sensitive chamber is varied. The varied pressure exerted on the areas of the spool end produces a hydrostatic force to move the spool linearly, which will rotate the spool reversely. Theoretical analysis is carried to the proposed valve and the effects of the key geometric parameters on the dynamic characteristics of the 2D valve and stability are investigated. Experiments are also designed to access to the characteristics of the valve working under direct and pilot operation. The 2D electrohydraulic valve can work properly for both direct operation and pilot operation. The hysteresis and frequency response are measured and the results are within the acceptable range in practical engineering application required of the directional proportional valve.

scholarly journals Looseness localization for bolted joints using Bayesian operational modal analysis and modal strain energy

2018 ◽  
Vol 10 (11) ◽  
pp. 168781401880869 ◽  
Author(s):  
Yu-Jia Hu ◽  
Wei-Gong Guo ◽  
Cheng Jiang ◽  
Yun-Lai Zhou ◽  
Weidong Zhu
Keyword(s):  
Modal Analysis ◽  
Strain Energy ◽  
Damage Index ◽  
Operational Modal Analysis ◽  
Modal Identification ◽  
Bolted Joints ◽  
Mode Shapes ◽  
Bolted Connections ◽  
Modal Strain Energy ◽  
Beam Structures

Bayesian operational modal analysis and modal strain energy are employed for determining the damage and looseness of bolted joints in beam structures under ambient excitation. With this ambient modal identification technique, mode shapes of a damaged beam structure with loosened bolted connections are obtained based on Bayesian theory. Then, the corresponding modal strain energy can be calculated based on the mode shapes. The modal strain energy of the structure with loosened bolted connections is compared with the theoretical one without bolted joints to define a damage index. This approach uses vibration-based nondestructive testing of locations and looseness of bolted joints in beam structures with different boundary conditions by first obtaining modal parameters from ambient vibration data. The damage index is then used to identify locations and looseness of bolted joints in beam structures with single or multiple bolted joints. Furthermore, the comparison between damage indexes due to different looseness levels of bolted connections demonstrates a qualitatively proportional relationship.

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