Damage identification based on wavelet packet analysis method

2016 ◽  
Vol 52 (1-2) ◽  
pp. 407-414 ◽  
Author(s):  
Yijin Chen ◽  
Shilin Xie ◽  
Xinong Zhang
Keyword(s):  
Damage Identification ◽  
Wavelet Packet ◽  
Analysis Method ◽  
Wavelet Packet Analysis

The Research of Gantry Crane Girder Damage Problem by Modal Analysis Method

2014 ◽  
Vol 578-579 ◽  
pp. 872-876
Author(s):  
Xiao Peng Nie ◽  
Xin Gang Li ◽  
Hong Wei Fan ◽  
Ke Qin Ding ◽  
Li Bin Xu
Keyword(s):  
Numerical Simulation ◽  
Wavelet Analysis ◽  
Static Analysis ◽  
Damage Identification ◽  
Three Dimensional ◽  
Gantry Crane ◽  
Analysis Method ◽  
Ansys Software ◽  
Vibration Equation ◽  
Damage Location

most crane damage identification of the work has focused on the static analysis, that can't explain whether the crane has a damage or not by this way. So the paper explained the modal signal to analysis this problem , Used 300 tons gantry crane’s beam for background and ANSYS software as a tool was used for numerical simulation. The purpose is to find difference between the damage beam of the crane and health one,because if there was a damage on the beam , the formations and frequency will be changed. This theory of analysis is based on the vibration equation. In order to illustrate it better, the wavelet analysis method as a tool has been used ,in this case the signal was filtered, we can judge the damage location from the three dimensional curve. The basic aim of this paper is to arrive at a better way to judge the damage.Through the above analysis, the results proved the author's idea, identify structural’s damage basically, but it still need further research.

Interval Analysis Method for Damage Identification of Structures

AIAA Journal ◽  
2010 ◽  
Vol 48 (6) ◽  
pp. 1108-1116 ◽  
Author(s):  
Xiaojun Wang ◽  
Haifeng Yang ◽  
Zhiping Qiu
Keyword(s):  
Interval Analysis ◽  
Damage Identification ◽  
Analysis Method ◽  
Interval Analysis Method

scholarly journals A review of railway sanding system research: Wheel/rail isolation, damage, and particle application

2019 ◽  
Vol 234 (6) ◽  
pp. 567-583 ◽  
Author(s):  
WA Skipper ◽  
A Chalisey ◽  
R Lewis
Keyword(s):  
Gap Analysis ◽  
Academic Research ◽  
Surface Damage ◽  
Analysis Method ◽  
Negative Effects ◽  
Abrasive Particles ◽  
Positive Effects ◽  
Industry Research ◽  
Air Stream ◽  
Railway Industry

This paper reviews the academic and industrial research conducted into the practical aspects of using abrasive particles in the wheel/rail contact, such as: wheel/rail isolation, surface damage, and the application of the particles into the contact. Abrasive particles are applied to the wheel/rail contact to restore traction when low adhesion situations exist on the rail head; this process is referred to as “sanding” because sand particles are the preferred particle type in the railway industry. This aspect of sanding was covered in another sanding review. Currently, particles are applied either by firing dry particles into the wheel/rail contact via an air stream or by suspending them in a gel which can be applied using train-borne or trackside methods. The papers looked at in this review were scrutinised using a gap analysis method which grades each paper based on seven criteria, these criteria assessed: whether the papers had been peer reviewed, whether the conclusions matched the results, the range of testing scales used, and the presence of fundamental modelling work. When the findings of the research in this review were analysed, it was apparent that the negative effects of sanding (damage and isolation) have not been researched in much depth compared to its positive effects (adhesion restoration and leaf layer removal). In addition, the academic research that has been conducted has not been taken forward by industry, and industry research has not been studied in more depth by academia, suggesting a communication gap between the two branches of research; this was also the case for research into application methods.

Repeatability Estimation in Galling Resistance Testing

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Scott R. Hummel ◽  
Jeffrey Helm
Keyword(s):  
Probabilistic Approach ◽  
Surface Damage ◽  
Severe Form ◽  
Test Method ◽  
Resistance Testing ◽  
Test Results ◽  
Analysis Method ◽  
Astm Method ◽  
Mechanical Surface ◽  
Extensive Plastic Deformation

Galling is a severe form of mechanical surface damage, commonly observed in metals, that is accompanied by adhesive transfer, extensive plastic deformation, and/or cold-welding of the mating surfaces. It can lead to seizure or rapid failure of machine components. Stainless steels are particularly prone to galling. A new galling test and analysis method that reflects the statistical nature of galling is described. The new ASTM method (G196), which embodies a probabilistic approach to galling, is superior to an older ASTM test method (G98), which produces only a single threshold stress for a given combination of materials. A computer-modeled experiment involving a 300 series stainless steel is used to illustrate how the enhanced analysis can be applied to determine the repeatability of galling test results.

Interval Analysis Method for Structural Damage Identification Based on Multiple Load Cases

2012 ◽  
Vol 79 (5) ◽  
Author(s):  
Xiaojun Wang ◽  
Haifeng Yang ◽  
Lei Wang ◽  
Zhiping Qiu
Keyword(s):  
Interval Analysis ◽  
Structural Damage ◽  
Damage Identification ◽  
Probabilistic Method ◽  
Measurement Data ◽  
Analysis Method ◽  
Multiple Load Cases ◽  
Interval Analysis Method ◽  
Structural Damage Identification ◽  
Multiple Load

Based on the measured static displacements, an improved interval analysis technique was proposed for the structural damage identification. Due to the scarcity of uncertain information, the uncertainties were considered as interval numbers in this paper. Via the first-order Taylor series expansion, the interval bounds of the elemental stiffness parameters of undamaged and damaged structures are respectively obtained. The structural damage was detected by the quantitative measure of the possibility of damage existence in elements, which was more reasonable than the probability of damage existence in the condition of less sample points for the measurement data. Furthermore, the classic interval analysis method was improved by adopting the membership-set identification and two-step model updating procedure to make identification results more accurate. An uncertain truss structure was employed for damage identification, the damage identification results obtained by interval analysis method and probabilistic method, respectively, were compared. Moreover, the effects on the detection results of the damage level and uncertainty level subjected to single or multiple load cases were studied as well. The numerical example shows that the wide intervals resulting from the interval operation can be narrowed by the improved nonprobabilistic approach, and the feasibility and effectiveness of the present method were validated.

Surface Structure in Microtomed Sections Caused by Glass and Diamond Knives

1971 ◽  
Vol 29 ◽  
pp. 456-457
Author(s):  
J. Temple Black ◽  
William G. Boldosser
Keyword(s):  
Plastic Deformation ◽  
Epoxy Resin ◽  
Carbon Coating ◽  
Surface Damage ◽  
Body Angle ◽  
Normal Manner ◽  
Bottom Side ◽  
Cutting Direction ◽  
Made In ◽  
Diamond Knife

Ultramicrotomy produces plastic deformation in the surfaces of microtomed TEM specimens which can not generally be observed unless special preparations are made. In this study, a typical biological composite of tissue (infundibular thoracic attachment) infiltrated in the normal manner with an embedding epoxy resin (Epon 812 in a 60/40 mixture) was microtomed with glass and diamond knives, both with 45 degree body angle. Sectioning was done in Portor Blum Mt-2 and Mt-1 microtomes. Sections were collected on formvar coated grids so that both the top side and the bottom side of the sections could be examined. Sections were then placed in a vacuum evaporator and self-shadowed with carbon. Some were chromium shadowed at a 30 degree angle. The sections were then examined in a Phillips 300 TEM at 60kv.Carbon coating (C) or carbon coating with chrom shadowing (C-Ch) makes in effect, single stage replicas of the surfaces of the sections and thus allows the damage in the surfaces to be observable in the TEM. Figure 1 (see key to figures) shows the bottom side of a diamond knife section, carbon self-shadowed and chrom shadowed perpendicular to the cutting direction. Very fine knife marks and surface damage can be observed.

Quantitative surface damage studies by H.R.E.M.

1989 ◽  
Vol 47 ◽  
pp. 632-633
Author(s):  
S. R. Singh ◽  
H. J. Fan ◽  
L. D. Marks
Keyword(s):  
Solar Wind ◽  
Quantitative Analysis ◽  
Surface Science ◽  
Surface Damage ◽  
Space Environment ◽  
Oxygen Desorption ◽  
The Past ◽  
Diffusion Controlled ◽  
Original Observation ◽  
Substantial Interest

Since the original observation that the surfaces of materials undergo radiation damage in the electron microscope similar to that observed by more conventional surface science techniques there has been substantial interest in understanding these phenomena in more detail; for a review see. For instance, surface damage in a microscope mimics damage in the space environment due to the solar wind and electron beam lithographic operations.However, purely qualitative experiments that have been done in the past are inadequate. In addition, many experiments performed in conventional microscopes may be inaccurate. What is needed is careful quantitative analysis including comparisons of the behavior in UHV versus that in a conventional microscope. In this paper we will present results of quantitative analysis which clearly demonstrate that the phenomena of importance are diffusion controlled; more detailed presentations of the data have been published elsewhere.As an illustration of the results, Figure 1 shows a plot of the shrinkage of a single, roughly spherical particle of WO3 versus time (dose) driven by oxygen desorption from the surface.

Study of Tip-Surface Interactions in Scanning Tunneling Microscopy (STM) by Reflection Electron Microscopy (REM)

1990 ◽  
Vol 48 (1) ◽  
pp. 320-321
Author(s):  
W. Lo ◽  
J.C.H. Spence ◽  
M. Kuwabara
Keyword(s):  
High Resolution ◽  
Elastic Strain ◽  
Tunneling Current ◽  
Surface Damage ◽  
Surface Interactions ◽  
Graphite Surface ◽  
Scanning Tunneling ◽  
Large Area ◽  
Tunneling Microscopy ◽  
High Resolution Tem

Work on the integration of STM with REM has demonstrated the usefulness of this combination. The STM has been designed to replace the side entry holder of a commercial Philips 400T TEM. It allows simultaneous REM imaging of the tip/sample region of the STM (see fig. 1). The REM technique offers nigh sensitivity to strain (<10−4) through diffraction contrast and high resolution (<lnm) along the unforeshortened direction. It is an ideal technique to use for studying tip/surface interactions in STM.The elastic strain associated with tunnelling was first imaged on cleaved, highly doped (S doped, 5 × 1018cm-3) InP(110). The tip and surface damage observed provided strong evidence that the strain was caused by tip/surface contact, most likely through an insulating adsorbate layer. This is consistent with the picture that tunnelling in air, liquid or ordinary vacuum (such as in a TEM) occurs through a layer of contamination. The tip, under servo control, must compress the insulating contamination layer in order to get close enough to the sample to tunnel. The contaminant thereby transmits the stress to the sample. Elastic strain while tunnelling from graphite has been detected by others, but never directly imaged before. Recent results using the STM/REM combination has yielded the first direct evidence of strain while tunnelling from graphite. Figure 2 shows a graphite surface elastically strained by the STM tip while tunnelling (It=3nA, Vtip=−20mV). Video images of other graphite surfaces show a reversible strain feature following the tip as it is scanned. The elastic strain field is sometimes seen to extend hundreds of nanometers from the tip. Also commonly observed while tunnelling from graphite is an increase in the RHEED intensity of the scanned region (see fig.3). Debris is seen on the tip and along the left edges of the brightened scan region of figure 4, suggesting that tip abrasion of the surface has occurred. High resolution TEM images of other tips show what appear to be attached graphite flakes. The removal of contamination, possibly along with the top few layers of graphite, seems a likely explanation for the observed increase in RHEED reflectivity. These results are not inconsistent with the “sliding planes” model of tunnelling on graphite“. Here, it was proposed that the force due to the tunnelling probe acts over a large area, causing shear of the graphite planes when the tip is scanned. The tunneling current is then modulated as the planes of graphite slide in and out of registry. The possiblity of true vacuum tunnelling from the cleaned graphite surface has not been ruled out. STM work function measurements are needed to test this.

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