Evaluation method for tooth wear of roller bits based on the fractal dimension of the rock surface

2021 ◽  
pp. 110039
Author(s):  
Changhao Wang ◽  
Xiaoming Wang ◽  
Shibin Li ◽  
Yuxuan Jiao ◽  
Runyu Yang ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Evaluation Method ◽  
Tooth Wear ◽  
Rock Surface

Research of Coal Pores and Integrity Evaluation Method Based on Fractal Theory

2014 ◽  
Vol 670-671 ◽  
pp. 258-262 ◽  
Author(s):  
Ji Li ◽  
Xin Wu
Keyword(s):  
Fractal Dimension ◽  
Coal Sample ◽  
Evaluation Method ◽  
Structural Integrity ◽  
Gas Adsorption ◽  
Fractal Theory ◽  
Physical And Mechanical Properties ◽  
Box Dimension ◽  
Sem Images ◽  
Sem Image

Coal is a natural porous media, its porosity and structural integrity influenced the gas adsorption and desorption characteristics greatly, as well as physical and mechanical properties of coal. Scanning electron microscopy (SEM) is applied to acquire SEM image of four kinds of coal samples at different zoom levels, and the box dimension can be worked out based on the pore preprocessing of SEM images. Then, the numerical value of box dimension is used to describe the development degree of the four kinds of coal sample and four development degrees’ sequence. At last, the intrinsic relevance between fractal dimension and other parameters is analyzed through mathematic method. The results show as follows: coal sample has self-similarity characteristic; the fractal dimension is related to both the total number of pores and porosity degree; the data of the coal pore, analyzed through fractal dimension, are consistent with that through traditional method; what’s more, fractal dimension has more advantages in describing accuracy and simplicity.

scholarly journals Research on Health Evaluation Method of Tank Diesel Engine

2019 ◽  
Vol 2019 ◽  
pp. 1-21
Author(s):  
X.-M. Zhang ◽  
D. X. Zhou ◽  
M. Chen
Keyword(s):  
Fractal Dimension ◽  
Diesel Engine ◽  
Evaluation Method ◽  
Working Condition ◽  
Health Condition ◽  
Health Evaluation ◽  
Quantitative Expression ◽  
Comprehensive Health ◽  
Real Vehicle ◽  
Deceleration Time

The idea of diesel engine health evaluation is put forward, and the calculation flow, fast algorithm, and influencing factors of wavelet fractal dimension are analyzed. Through the real vehicle experiment, the corresponding relationship between the fractal dimension of the wavelet and the health condition of the diesel engine is calculated and analyzed. Three quantitative expression parameters, age health degree, dimension health degree, and comprehensive health degree, are defined considering the age and working condition of diesel engine. Finally, the consistency of health degree with vibration intensity, acceleration time, deceleration time, and fuel consumption was confirmed. It has been proved that it is feasible to evaluate the health of diesel engine with health degree.

Analysis of Cracking Processes of Sandstone in Rockburst Test

2012 ◽  
Vol 256-259 ◽  
pp. 1052-1059
Author(s):  
De Jian Li ◽  
Fei Zhao ◽  
Run Jie Ma ◽  
Li Qiang Han ◽  
Xiao Hu Wu
Keyword(s):  
Growth Rate ◽  
Fractal Dimension ◽  
Crack Propagation ◽  
High Speed ◽  
Fractal Dimensions ◽  
Rock Surface ◽  
Horizontal Line ◽  
High Speed Camera ◽  
Camera System ◽  
Very High

High speed camera system is used to record crack propagation on rock surface during the lab rocburst experiment. This paper presents the specific analytical method of crack propagation with high speed images. Crack propagation types and directions are briefly described, and the lengths, growth rate and fractal dimension of cracks are calculated. The results show that the crack grows mainly along the horizontal line on the unloading surface, at a low speed before rockburst and reaches a very high speed abruptly near the burst point. The fractal dimensions demonstrated that the crack turns to be rough when rockburst happens. The study on the crack propagation is benefit to the understanding on the mechanism of rockburst.

Box-counting methods to directly estimate the fractal dimension of a rock surface

2014 ◽  
Vol 314 ◽  
pp. 610-621 ◽  
Author(s):  
T. Ai ◽  
R. Zhang ◽  
H.W. Zhou ◽  
J.L. Pei
Keyword(s):  
Fractal Dimension ◽  
Rock Surface ◽  
Box Counting ◽  
Counting Methods

Evaluation of WEDM Surface Quality

2010 ◽  
Vol 97-101 ◽  
pp. 4080-4083 ◽  
Author(s):  
Lei Geng ◽  
Hua Yan Zhong
Keyword(s):  
Surface Roughness ◽  
Fractal Dimension ◽  
Spectral Density ◽  
Surface Topography ◽  
Surface Quality ◽  
Power Spectral Density ◽  
Evaluation Method ◽  
Fractal Theory ◽  
Machined Surface ◽  
Power Spectral

The formation of WEDM surface is a complicated process. There are many factors which make machined surface topography have the characteristics of complex and irregular, and impact using performance of parts. The work investigated microscopic features of the WEDM surface topography based on power spectral density and fractal theory, and proposed power spectral density evaluation method of the WEDM surface. The fractal dimension of the WEDM surface was calculated by structure function method. The physical meaning of the fractal dimension of the WEDM surface was described. The result shows that topography of the WEDM surface exhibits strong fractal characteristics within a certain scale. The processing parameters and pulse power performance will affect the fractal dimension D. The fractal dimension D has a certain relationship with the surface roughness Ra. It is more reasonable to use the fractal dimension D as well as the surface roughness Ra together to evaluate WEDM surface quality.

Optimal button arrangement of a percussion drill bit and its operating condition for improving drilling efficiency

2017 ◽  
Vol 232 (16) ◽  
pp. 2887-2898 ◽  
Author(s):  
Hoon Kang ◽  
Jin-Young Park ◽  
Jung-Woo Cho ◽  
Jin-Seok Jang ◽  
Kun-Woo Kim ◽  
...  
Keyword(s):  
Evaluation Method ◽  
Optimal Solution ◽  
Operating Conditions ◽  
Rock Surface ◽  
Drill Bit ◽  
Operating Condition ◽  
Drilling Performance ◽  
Impact Area ◽  
Specific Operating Condition ◽  
The Impact

This paper proposes an optimal button arrangement of a percussion drill bit and its operating condition to improve drilling efficiency. A new evaluation method is introduced for the button arrangement that utilizes the superimposed impact area, blank area, and drilling deviation moment as the quantitative indices to evaluate the impact of buttons on the rock surface. To determine the optimal button arrangement and its operating conditions, a progressive metamodel-based design optimization was conducted using the new evaluation indices as the analysis response, and then the optimal solution was determined through iteration. Consequently, all the button evaluation indices were reduced significantly and the impact areas were distributed uniformly under a specific operating condition. Additionally, the drilling performances of the optimal button arrangement were investigated according to the operating conditions to obtain the maximum drilling performance in terms of the drilling machine operation.

scholarly journals Evaluation of particle size distribution of granular blasting materials based on the fractal theory

2019 ◽  
Vol 11 (10) ◽  
pp. 168781401988156 ◽  
Author(s):  
Jiejie Ji ◽  
Qiang Yao ◽  
Faming Wu ◽  
Hongtao Li
Keyword(s):  
Particle Size ◽  
Fractal Dimension ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Evaluation Method ◽  
Fractal Theory ◽  
Distribution Model ◽  
Uniformity Coefficient ◽  
Functional Relationships ◽  
Fine Grain

The particle size distribution of granular blasting materials has a vital influence on the filling quality of earth-rockfill dams. The engineering experience-based method used to evaluate the particle size distribution has shortcomings at both the theoretical and practical aspects. This article proposes a new evaluation method based on the fractal theory. Grading sieve tests on granular materials, mass fractal analysis of particle size distribution, and a probability distribution model test of the characteristic parameters are used to revise the functional relationships between the fractal dimension D and the uniformity coefficient/curvature coefficient ( Cu/ Cc) of the grading curve. The feasibility of using D to evaluate the particle size distribution and the optimal fine grain content is then analyzed and determined. According to the results, the geometric shapes of the granular blasting materials have fractal characteristics, and their particle size distribution has a fractal distribution. The ranges of D where the rockfill and transition materials have a good particle size distribution are D = 2.254–2.529 and D = 2.358–2.559, corresponding to optimal fine grain content of 1.953%–11.805% and 10.268%–23.123%, respectively. Fractal dimension has a solid theoretical basis and strong practical applicability as an evaluation index for the particle size distribution of granular blasting materials.

A Suitability Evaluation Method Based on Fractal Dimension in Geomagnetism Matching Navigation

2012 ◽  
Vol 588-589 ◽  
pp. 994-997
Author(s):  
Ying Liang ◽  
Qing Yang Xu
Keyword(s):  
Fractal Dimension ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Suitability Evaluation ◽  
Fractal Characteristic ◽  
Region Selection ◽  
Fractal Characteristics ◽  
Characteristic Fractal Dimension ◽  
Geomagnetic Anomalies ◽  
Selection Of

The suitability evaluation has an important influence on suitable-matching region selection of geomagnetism matching navigation. Geomagnetic anomalies have a fractal characteristic. Fractal dimension can describe the self-similar characteristics and subtle changes of irregular, broken, uneven and infinite detail form of geomagnetic anomalies. A comprehensive evaluation function based on fractal characteristics was established, and the ranks of region suitability were gotten finally.

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