scholarly journals Response Analysis of a Plate Structure under Double Source Excitation by FBG Sensors

2018 ◽  
Vol 14 (07) ◽  
pp. 108
Author(s):  
Cai Li ◽  
Huang Xiao ◽  
Meng Lijun
Keyword(s):  
Simulation Analysis ◽  
Experimental System ◽  
Detection Methods ◽  
Practical Significance ◽  
Response Analysis ◽  
Destructive Testing ◽  
Plate Structure ◽  
Result Show ◽  
Actual Operation ◽  
Source Excitation

The nondestructive assessments play a key role for condition monitoring of in-service structures. At present, many non-destructive testing methods have been widely applied, but actual operation environment has the characteristics of multiple random, which makes the effects of multiple excitation sources. While the traditional detection methods only consider the main sources of motivation and ignore the other sources, which will bring a bigger error. So the multi-source excitation method has practical significance. Here this paper puts forward a double source excitation technique for plate structure based on fiber Bragg grating sensor, which is used to receive the waves in the plate. First, measuring principle of double source excitation and demodulation principle of the FBG sensor are introduced. Then simulation analysis in the double source excitation field is devoted, whose results lay the foundation for the detection in the plate. On this basis, the experimental system is built and the influence of different parameters are analyzed such as frequency, phase. Then this double source excitation-FBG sensing technique is applied to damage detection by envelope analysis, whose result show that this double source excitation-FBG sensing method for the plate structure is sensitive to crack damage.

Study on Range of the Sampling Period of the Electro-Hydraulic Position Sampling Control System Based on PLC

2010 ◽  
Vol 152-153 ◽  
pp. 58-62
Author(s):  
He Ying Bian ◽  
Yan Hui Wang
Keyword(s):  
Control System ◽  
Closed Loop ◽  
Simulation Analysis ◽  
Sampling Period ◽  
System Stability ◽  
Practical Significance ◽  
Theory Of Sampling ◽  
Actual Operation ◽  
Simulation Results ◽  
The Stability

The paper built electro-hydraulic position closed-loop sampling control system based on PLC, established mathematical model of this system by applying theory of sampling control and determines the range of the sampling period T under the stability of the system according to system stability theory. Then carried out simulation analysis and experimental verification in the range of T, provided with the method determined the range of sampling period. The results showed that simulation results of this model were consistent with the actual operation of the system , the method and sampling period be chosen have some practical significance.

scholarly journals Multiview deep learning based on tensor decomposition and its application in fault detection of overhead contact systems

2021 ◽  
Author(s):  
Xuewu Zhang ◽  
Yansheng Gong ◽  
Chen Qiao ◽  
Wenfeng Jing
Keyword(s):  
High Speed ◽  
Tensor Decomposition ◽  
Detection Methods ◽  
Detection Accuracy ◽  
Feature Maps ◽  
Training Time ◽  
Detection Model ◽  
Railway Line ◽  
Result Show ◽  
Deep Layers

AbstractThis article mainly focuses on the most common types of high-speed railways malfunctions in overhead contact systems, namely, unstressed droppers, foreign-body invasions, and pole number-plate malfunctions, to establish a deep-network detection model. By fusing the feature maps of the shallow and deep layers in the pretraining network, global and local features of the malfunction area are combined to enhance the network's ability of identifying small objects. Further, in order to share the fully connected layers of the pretraining network and reduce the complexity of the model, Tucker tensor decomposition is used to extract features from the fused-feature map. The operation greatly reduces training time. Through the detection of images collected on the Lanxin railway line, experiments result show that the proposed multiview Faster R-CNN based on tensor decomposition had lower miss probability and higher detection accuracy for the three types faults. Compared with object-detection methods YOLOv3, SSD, and the original Faster R-CNN, the average miss probability of the improved Faster R-CNN model in this paper is decreased by 37.83%, 51.27%, and 43.79%, respectively, and average detection accuracy is increased by 3.6%, 9.75%, and 5.9%, respectively.

Dynamic Analysis of DVG 850 High-Speed Machining Center

2012 ◽  
Vol 487 ◽  
pp. 203-207
Author(s):  
Gong Xue Zhang ◽  
Xiao Kai Shen
Keyword(s):  
High Speed ◽  
Simulation Analysis ◽  
Response Analysis ◽  
Improved Method ◽  
Analysis Software ◽  
Element Analysis ◽  
Harmonic Response ◽  
Machining Center ◽  
Calculation Results ◽  
Harmonic Response Analysis

Purpose, with the application of workbench finite element analysis software, get the analysis results of DVG 850 high-speed vertical machining center via the modal analysis and harmonic response analysis. Use the calculation results for reference, put forward the improved method, and prove the credibility of the simulation analysis by testing DVG 850 prototype.

scholarly journals Analysis of Propagation and Distribution Characteristics of Leakage Acoustic Waves in Water Supply Pipelines

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5450
Author(s):  
Yunfei Li ◽  
Yang Zhou ◽  
Ming Fu ◽  
Fan Zhou ◽  
Zhaozhao Chi ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Water Supply ◽  
Acoustic Waves ◽  
Simulation Analysis ◽  
Acoustic Signals ◽  
Detection Methods ◽  
Acoustic Analogy ◽  
Acoustic Wave Propagation ◽  
Source Characteristics ◽  
Water Supply Pipeline

Leakage detection methods based on the analysis of leakage acoustic signals provide an effective technical approach for detecting small leaks in water supply pipelines. From a technical perspective, the study of the propagation characteristics of acoustic waves generated by the leakage in the water supply pipeline is necessary for detecting the leak location on the basis of acoustic signals. In this study, a 3D transient leakage acoustic wave propagation equation was derived by combining the principles of fluid dynamics and Lighthill acoustic analogy theory. The propagation of the leakage-induced noise in water supply pipeline was modelled theoretically. We simulated the propagation of a leakage acoustic wave under different conditions for different target scenarios encountered in actual pipeline inspections. Specifically, we analysed the effect of different factors, such as the pipe size and acoustic source characteristics, on acoustic propagation. Finally, the simulated experiments were practically performed using a self-designed simulated water supply pipeline and self-developed spherical water supply pipeline detector to validate the simulation analysis. The results of this study provide a theoretical guidance and basis for the analysis of characteristics of leakage acoustic wave signals and the recognition of leakage conditions in water supply pipelines.

Nondestructive Damage Detection of Bridges: A Status Review

2001 ◽  
Vol 4 (2) ◽  
pp. 75-91 ◽  
Author(s):  
Xiaotong Wang ◽  
Chih-Chen Chang ◽  
Lichu Fan
Keyword(s):  
Damage Detection ◽  
Rapid Development ◽  
Low Frequency ◽  
Basic Research ◽  
Digital Signal ◽  
Point Of View ◽  
Detection Methods ◽  
Measured Signal ◽  
Destructive Testing ◽  
Bridge Damage

The recent advances in detecting and locating damage in bridges by different kinds of non-destructive testing and evaluation (NDT&E) methods are reviewed. From the application point of view, classifications for general bridge components and their damage types are presented. The relationships between damage, bridge components, and NDT&E techniques are summarized. Many useful WEB sources of NDT&E techniques in bridge damage detection are given. It is concluded that: (1) vibration-based damage detection methods are successful to a certain extent, especially when the overall damage is significant and, low frequency vibration can identify those areas where more detailed local inspection should be concentrated; (2) robust identification techniques that are able to locate damage based on realistic measured data sets still seem a long way from reality, and, basic research is still necessary in the mean time; (3) the rapid development of computer technology and digital signal processing (DSP) techniques greatly impacts upon the conventional NDT techniques, especially in control data processing and data displaying, as well as in simulation and modeling; (4) most of the NDT&E techniques introduced in this paper have their own practical commercial systems, but the effort required for combining the theoretical, experimental and engineering achievements, is still a challenging task when establishing the relationship between the unknown quantities and the measured signal parameters and specialised instruments have shown great advantages for doing some things more effectively than general ones; (5) in bridge damage detection, a problem usually requires the application of different NDT&E techniques; two or more independent techniques are needed to enable confidence in the results.

Global Structure Strength Analysis of SWATH Based on Direct Calculate Method

2014 ◽  
Vol 633-634 ◽  
pp. 1002-1006
Author(s):  
Chun Bo Zhen ◽  
Liang Feng ◽  
Guo Chun Lu ◽  
Yuan Hang Hou
Keyword(s):  
Stress Concentration ◽  
Boundary Conditions ◽  
Element Model ◽  
Global Structure ◽  
Strength Analysis ◽  
Response Analysis ◽  
Structure Response ◽  
Result Show ◽  
Design Loads ◽  
Structure Strength

The stress concentration of SWATH’s cross-deck structure is serious and the problem of its structure strength appears particularly important. In this paper, A 3-D global element model of SWATH was built, the design Loads, load cases and boundary conditions were studied. on the base of that, the structure response analysis was completed. The result show that the global ship’s stress is small in all load cases of head seas and oblique seas, and the bulkheads have serious stress concentration phenomenon in beam seas.The result can offer the reference for SWATH’s design and development.

Structural Health Monitoring Experimental System Implemented in a Turboprop Commercial Aircraft

2007 ◽  
Vol 347 ◽  
pp. 311-317
Author(s):  
Igor Bovio ◽  
Leonardo Lecce
Keyword(s):  
Structural Damage ◽  
Damage Index ◽  
Experimental System ◽  
Experimental Tests ◽  
Processing Technique ◽  
Commercial Aircraft ◽  
Destructive Testing ◽  
Before And After ◽  
Neural Network Algorithm ◽  
Testing Field

The purpose of the paper is to present an innovative application within the Non Destructive Testing field based upon vibration measurements developed by the authors, and already tested for analysing damage of many structural elements. After having tested this application on different test articles in laboratory condition, experimental tests have been executed, in collaboration with the ATR company, on a turboprop ATR-72 aircraft, in order to validate the technique on a real aeronautical structure. The monitoring system have operated an off-line check on the structure, during the aircraft ground operations, as if it were a normal maintenance procedure. The results are reported in the paper. This proposed new method is based upon the acquisition and comparison of the Frequency Response Functions (FRFs) of the monitored structure before and after damage occurs. Structural damage modify the dynamic behaviour of a structure affecting its mass, stiffness and damping, and consequently the FRFs of a damaged structure, when compared with the FRFs of its sound configuration, making the identification, localization and quantification of damage possible. The activities presented in the paper focus mainly on a new FRFs processing technique based upon the determination of a representative “Damage Index” for identifying and analysing damage. Furthermore, a dedicated neural network algorithm has been elaborated to develop an automatic system which recognises positive samples, “healthy” states of the analysed structure, discarding negative ones, “damaged or perturbed” states of the analysed structure. From an architectural standpoint, piezoceramic patches have been used as both actuators and sensors.

Imaging and Testing of Ultrasonic Sh Guided Waves in Plate with Lap Welding Structure

2011 ◽  
Vol 301-303 ◽  
pp. 603-609
Author(s):  
Xin Jie Zhu ◽  
Zan Dong Han ◽  
Dong Du ◽  
Yi Fang Chen ◽  
Ke Yi Yuan
Keyword(s):  
Guided Waves ◽  
Experimental System ◽  
Destructive Testing ◽  
Long Distance ◽  
Testing Zone ◽  
Lap Welding ◽  
Corrosion Defects ◽  
Synthetic Aperture Focusing ◽  
Non Destructive ◽  
Shear Horizontal

The imaging and testing of ultrasonic SH (Shear Horizontal) guided waves may be used into testing and SHM (Structure Health Monitoring) of industrial plate with welding structure in service, which have much more important applied potential. During imaging and testing for steel plate with lap welding structure, photoelastic experiment on propagation of guided waves in Plexiglas plate was studied to clearly see the excellent advantages of SH guided waves. The mode of SH guided waves was analyzed to select the zero order mode SH0 and the SH guided waves transducer with SH0 mode was developed. Based on the synthetic aperture focusing method，a multichannel ultrasonic imaging and testing experimental system of ultrasonic SH guided waves was constructed，the imaging of plate with lap welding structure was mainly studied. The research results shows the ultrasonic SH guided waves and the transducers are fit for long distance testing for the plate with lap welding structure. The ultrasound scattering nearby the weld may cause a blind testing zone, about 150 mm wide, in which the less size corrosion defects at the blind zone could not be revealed in image, so as to lead to defects “no testing”. The imaging and testing of ultrasonic SH guided waves would be used for non-destructive testing of plate with lap welding structure, which image both can characterize the corrosion defects and lap welding structure, and realize the precise location of the weld. The proposed research provides important foundation for improving ultrasonic guided waves imaging and testing quality and SHM of industrial in-site plate with lap welding and larger size.

Study on Effect of Seismic Joint to Seismic Response of Tunnel Passing through Fault

2013 ◽  
Vol 482 ◽  
pp. 252-255 ◽  
Author(s):  
Feng Gao ◽  
Xiao Gang Shu ◽  
Dian Li Xue ◽  
Jiao Liu
Keyword(s):  
Seismic Response ◽  
Underground Structure ◽  
Element Model ◽  
Separation Distance ◽  
Practical Significance ◽  
Seismic Resistance ◽  
Response Analysis ◽  
Analysis Model ◽  
Fault Fracture Zone ◽  
Tunnel Depth

As underground structure, the tunnel itself has good anti-seismic performance, but in recent years, according to a large number of investigation data about the earthquake disaster for tunnel, we find that the tunnel passing through the fault fracture zone is quite easy to be destroyed seriously. Therefore, developing dynamic response analysis and shock absorption measures has great practical significance. According to the characteristics of tunnel passing through fault and the tunnel depth, considering a certain proportion relationship in finite element model, the analysis model for tunnel seismic joint is established. Finally comparing the results comprehensively, we discuss the effect of the different setting location and setting separation distance of seismic joint to seismic response of tunnel passing through fault. From the work we have done, we get the seismic joint which is good for tunnel seismic resistance. This method is expected to be adopted as reference to the similar projects.

Dynamic Characteristic and Experiment Research of a Rotor-Bearing System Supported by Oil-Film

2010 ◽  
Vol 29-32 ◽  
pp. 1732-1737
Author(s):  
Chao Feng Li ◽  
Ji Shuang Dai ◽  
Xiao Peng Li ◽  
Bang Chun Wen
Keyword(s):  
Reduction Method ◽  
Three Dimensional ◽  
Experimental System ◽  
Rotor System ◽  
Practical Significance ◽  
Dimension Reduction Method ◽  
Experiment Research ◽  
Nonlinear Dynamical ◽  
Rotor Bearing ◽  
Fixed Interface

The FEM was employed to establish a nonlinear dynamical model of a rotor-bearing experimental system. The fixed interface mode synthesis dimension reduction method was adopted to to save the computing time.The Newmark-β method was employed to solve the reduced model numerically. And the three-dimensional spectrogram, bifurcation diagram, three-dimensional amplitude diagram, chart of axis trajectory, etc were used to analyze the nonlinear characteristic of the dynamic system comparing with those results of the experimental system. Results show that the numerical dynamic model can accurately reflect the characteristics of the nonlinear experimental system. So, it is very important practical significance to apply FEM and dimensional reduction theory into the research of the local nonlinear rotor system, which can provide more accurate verification and reference for the advanced nonlinear dynamic design of the complex rotor system.

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