Detection of Wear Condition of Micro Milling Cutters Based on Length Fractal Dimension

2014 ◽  
Vol 577 ◽  
pp. 697-700
Author(s):  
Zhi Qiang Wang ◽  
Gui Ying Zhang ◽  
Bin Liu
Keyword(s):  
Fractal Dimension ◽  
Time Domain ◽  
Fractal Dimensions ◽  
Experimental Results ◽  
New Method ◽  
Micro Milling ◽  
Vibration Signals ◽  
Reference Samples ◽  
Wear Condition

In this paper, a new method to realize online wear detection of micro-milling cutters based on length fractal dimension is proposed. On the basis of expression derivation of length fractal dimension, experiments are conducted. First, several cutters with different wear condition are chosen as reference samples. Their multi-section vibration signals in time-domain are collected and the clustering domain δ of each sample are obtained based on length fractal dimensions. Then, the vibration signals of tested cutters are monitored and analysed in time domain, thus their length fractal dimension are abstracted. Comparing the length fractal dimension of tested cutters with the clustering domain δ of reference samples, the wear condition of tested cutters are detected. The experimental results show that the length fractal dimension of each tested cutter falls in the clustering domain corresponding to the actual wear condition.

scholarly journals Bearing Fault Detection Using Multi-Scale Fractal Dimensions Based on Morphological Covers

2012 ◽  
Vol 19 (6) ◽  
pp. 1373-1383 ◽  
Author(s):  
Pei-Lin Zhang ◽  
Bing Li ◽  
Shuang-Shan Mi ◽  
Ying-Tang Zhang ◽  
Dong-Sheng Liu
Keyword(s):  
Fractal Dimension ◽  
Fault Diagnosis ◽  
Fractal Dimensions ◽  
Extraction Methods ◽  
Experimental Results ◽  
Vibration Signals ◽  
Bearing Fault ◽  
Bearing Fault Diagnosis ◽  
Multi Scale ◽  
Self Similar

Vibration signals acquired from bearing have been found to demonstrate complicated nonlinear characteristics in literature. Fractal geometry theory has provided effective tools such as fractal dimension for characterizing the vibration signals in bearing faults detection. However, most of the natural signals are not critical self-similar fractals; the assumption of a constant fractal dimension at all scales may not be true. Motivated by this fact, this work explores the application of the multi-scale fractal dimensions (MFDs) based on morphological cover (MC) technique for bearing fault diagnosis. Vibration signals from bearing with seven different states under four operations conditions are collected to validate the presented MFDs based on MC technique. Experimental results reveal that the vibration signals acquired from bearing are not critical self-similar fractals. The MFDs can provide more discriminative information about the signals than the single global fractal dimension. Furthermore, three classifiers are employed to evaluate and compare the classification performance of the MFDs with other feature extraction methods. Experimental results demonstrate the MFDs to be a desirable approach to improve the performance of bearing fault diagnosis.

Research on Tool Wear Based on Texture Fractal Dimension

2011 ◽  
Vol 66-68 ◽  
pp. 1163-1166
Author(s):  
Mao Jun Chen ◽  
Zhong Jin Ni ◽  
Liang Fang
Keyword(s):  
Fractal Dimension ◽  
Tool Wear ◽  
Surface Texture ◽  
Manufacturing Systems ◽  
Experimental Results ◽  
Machining Process ◽  
Work Piece ◽  
Automated Manufacturing ◽  
Automated Manufacturing Systems ◽  
Wear Condition

In automated manufacturing systems, one of the most important issues is the detection of tool wear during the machining process. The Hausdorff-Besicovitch (HB) dimension is used to analyze the feature of the surface texture of work-piece in this paper. The value of the fractal dimension of the work-piece surface texture tends to decrease with the machining process, due to the texture becoming more complex and irregular, and the tool wear is also becoming more and more serious. That can describe the inherent relationship between work-piece surface texture and tool wear. The experimental results demonstrate the probability of using the fractal dimension of work-piece surface texture to monitor the tool wear condition.

Multi-Dimensional Directional Spectrograms and Campbell (ZMOD) Diagrams for Rotating Machinery

1995 ◽  
Author(s):  
I. Bucher ◽  
D. J. Ewins ◽  
D. A. Robb ◽  
P. Schmiechen
Keyword(s):  
Rotating Machinery ◽  
Experimental Results ◽  
New Method ◽  
Frequency Content ◽  
Rotating Disc ◽  
Vibration Signals ◽  
Time Frequency ◽  
Spatial Response ◽  
Spatial Domains ◽  
Vibration Pattern

Abstract A new method for decomposition of vibration signals measured on rotating machinery is presented in this paper. The method uses a signal measured from a number of sensors to decompose the spatial response according to the direction of the progression of motion, the frequency content and the various wavelengths. For the simple case of shaft vibration, two sensors, horizontal and vertical, are used to separate the vibration pattern into forward and backward progressing components. For the case of a rotating disc, more sensors are required to further decompose the response into different wavelengths. This allows one to monitor and to identify potentially dangerous vibration patterns exhibiting large backward components. The method is shown to provide better resolution in the time-frequency (speed of rotation) and spatial domains by separating several, usually overlapping patterns. Several analytical and experimental results demonstrate the usefulness of the proposed method.

A New Method of Characterization on Microstructure of Casting Alloy

2011 ◽  
Vol 211-212 ◽  
pp. 122-126
Author(s):  
Zheng Liu ◽  
Xiao Mei Liu
Keyword(s):  
Fractal Dimension ◽  
Fractal Structure ◽  
A356 Alloy ◽  
Fractal Dimensions ◽  
Primary Phase ◽  
New Method ◽  
Casting Alloy ◽  
Microstructural Characteristics ◽  
Low Superheat

Microstructural characteristics of A356 alloy prepared by low superheat pouring were researched, and the fractal dimensions of morphology of primary phase in the alloy was calculated. The results indicated that morphology of primary phase in A356 alloy belonged to fractal structure, and the microstructural characteristics in the alloy can be characterized by fractal dimension. There were the different fractal dimensions for the morphology of primary phase prepared by the different process.

DEVELOPING A NEW METHOD FOR THE IDENTIFICATION OF MICROORGANISMS FOR THE FOOD INDUSTRY USING THE FRACTAL DIMENSION

Fractals ◽  
1994 ◽  
Vol 02 (03) ◽  
pp. 457-460 ◽  
Author(s):  
OSCAR CASTILLO ◽  
PATRICIA MELIN
Keyword(s):  
Quality Control ◽  
Fractal Dimension ◽  
Food Industry ◽  
Fractal Dimensions ◽  
New Method ◽  
Different Types ◽  
One To One

The fractal dimension can be a useful tool in the identification of microorganisms, because it can be experimentally shown that the colonies of different types of bacteria have different geometrical forms, and as a result of this fact different fractal dimensions. Our method of identification of microorganisms for the food industry, is based on the application of a one to one map between the different types of bacteria and their corresponding fractal dimension. The importance of this new method can be related to the need of making more efficient the task of the quality control lab of the food industry.

scholarly journals The Research on Information Representation of Φ-OTDR Distributed Vibration Signals

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Yanzhu Hu ◽  
Song Wang ◽  
Zhaoyang Wang ◽  
Yixin Zhang
Keyword(s):  
Time Domain ◽  
New Method ◽  
Signal Extraction ◽  
Signal Representation ◽  
Time Dimension ◽  
Excellent Performance ◽  
Vibration Signals ◽  
Time Domain Data ◽  
The Time Domain ◽  
Emd Method

This paper mainly focuses on the representable problem of Φ-OTDR distributed vibration signals. The research included a signal extraction part and a signal representation part. Firstly, in order to extract the better Φ-OTDR signal, the time-domain data should be fully preserved. The 2D-TESP method is used to extract data in this paper. There are 29 characters in the traditional TESP method. The characters’ number is reduced from 29 to 13 and the characters’ dimension is expanded from 1 to 2 in the 2D-TESP method. Secondly, in order to represent Φ-OTDR signal better, the characteristics of Φ-OTDR data and damped vibration signals are combined in the paper. The EMD method and the NMF method are combined to form the new method in the paper. Some parameters in the proposed method are optimized and adjusted by GA method. After Φ-OTDR data is represented by the proposed method, there is excellent performance both on the length dimension and on the time dimension. Lastly, some experiments are carried out according to the physical truth in this paper. The experiments are carried out in the semianechoic room. The methods of the paper have better performance. The methods are proved to be effective through these experiments.

Amplification of Signal Features Using Variance Fractal Dimension Trajectory

2012 ◽  
pp. 263-277
Author(s):  
Witold Kinsner ◽  
Warren Grieder
Keyword(s):  
Fractal Dimension ◽  
Time Domain ◽  
Speech Signal ◽  
Experimental Results ◽  
Unit Distance ◽  
Detection Techniques ◽  
Signal Features ◽  
The Individual ◽  
Selection Of

This paper describes how the selection of parameters for the variance fractal dimension (VFD) multiscale time-domain algorithm can create an amplification of the fractal dimension trajectory that is obtained for a natural-speech waveform in the presence of ambient noise. The technique is based on the variance fractal dimension trajectory (VFDT) algorithm that is used not only to detect the external boundaries of an utterance, but also its internal pauses representing the unvoiced speech. The VFDT algorithm can also amplify internal features of phonemes. This fractal feature amplification is accomplished when the time increments are selected in a dyadic manner rather than selecting the increments in a unit distance sequence. These amplified trajectories for different phonemes are more distinct, thus providing a better characterization of the individual segments in the speech signal. This approach is superior to other energy-based boundary-detection techniques. Observations are based on extensive experimental results on speech utterances digitized at 44.1 kilosamples per second, with 16 bits in each sample.

Experimental Study on NVH Performance of Midi Pure Electric Vehicle

2012 ◽  
Vol 152-154 ◽  
pp. 1852-1857 ◽  
Author(s):  
Hui Bin Li ◽  
Chen Xia Zhang ◽  
Quan Xi Li ◽  
Ting Jin ◽  
Ke Feng Wang
Keyword(s):  
Time Domain ◽  
Constant Velocity ◽  
Interior Noise ◽  
Experimental Results ◽  
Vibration Acceleration ◽  
Isolation Rate ◽  
Vibration Signals ◽  
The Poor ◽  
Electrical Vehicle ◽  
The One

Measurement of interior noise and vibration signals were conducted in accelerating and constant velocity driving conditions. By using time domain, frequency domain and 3D spectral array methods, the exterior noise, interior noise, the vibration acceleration of driver’s seat and suspension, the NVH characteristics of the Midi EU vehicle were analyzed. On the one hand, we find that the interior noise is larger than exterior noise under accelerating state, due to the cabin poorly sealing. On the other hand, because of the poor isolation rate of the driver’s seat, the vibration acceleration on the driver’s seat is very great and affecting the driver’s comfort. The experimental results also shows that the isolation rate of the suspension are relative good under different velocities. These experimental results will give help to further study of the NVH characteristic of the pure electrical vehicle.

A NEW METHOD FOR CALCULATING FRACTAL DIMENSIONS OF POROUS MEDIA BASED ON PORE SIZE DISTRIBUTION

Fractals ◽  
2018 ◽  
Vol 26 (01) ◽  
pp. 1850006 ◽  
Author(s):  
YUXUAN XIA ◽  
JIANCHAO CAI ◽  
WEI WEI ◽  
XIANGYUN HU ◽  
XIN WANG ◽  
...  
Keyword(s):  
Porous Media ◽  
Fractal Dimension ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Pore Space ◽  
Fractal Theory ◽  
Fractal Dimensions ◽  
New Method ◽  
Distribution Data

Fractal theory has been widely used in petrophysical properties of porous rocks over several decades and determination of fractal dimensions is always the focus of researches and applications by means of fractal-based methods. In this work, a new method for calculating pore space fractal dimension and tortuosity fractal dimension of porous media is derived based on fractal capillary model assumption. The presented work establishes relationship between fractal dimensions and pore size distribution, which can be directly used to calculate the fractal dimensions. The published pore size distribution data for eight sandstone samples are used to calculate the fractal dimensions and simultaneously compared with prediction results from analytical expression. In addition, the proposed fractal dimension method is also tested through Micro-CT images of three sandstone cores, and are compared with fractal dimensions by box-counting algorithm. The test results also prove a self-similar fractal range in sandstone when excluding smaller pores.

A Review on Fractals and Fracture, Part I: Calculating Fractal Dimensions by CAD Model

2011 ◽  
Vol 148-149 ◽  
pp. 818-821
Author(s):  
Asma A. Shariff ◽  
M. Hadi Hafezi
Keyword(s):  
Fractal Dimension ◽  
Fracture Surface ◽  
Fractal Geometry ◽  
Fractal Dimensions ◽  
Experimental Results ◽  
The Other ◽  
Cad Model ◽  
Cloud Of Points

The objective of this paper is to consider the use of fractal geometry as a tool for the study of non-smooth and discontinuous objects for which Euclidean coordinate is not able to fully describe their shapes. We categorized the methods for computing fractal dimension with a discussion into that. We guide readers up to the point they can dig into the literature, but with more advanced methods that researchers are developing. Considerations show that is necessary to understand the numerous theoretical and experimental results concerning searching of the conformality before evaluating the fractal dimension to our own objects. We suggested examining a cloud of points of growth of fracture surface at laboratory using CATIA - Digitized Shape Editor software in order to reconstruct the surface (CAD model). Then, the author carried out measurement/calculation of more accurate fractal dimension which are introduced by [1] in the other paper as Part II.

Sign in / Sign up

Export Citation Format

Share Document