Fractal Research in Metal Material Fracture Invalidation

2013 ◽  
Vol 703 ◽  
pp. 8-11
Author(s):  
Li Hui Guo ◽  
Wan Qiang Hu

Though there are a lot of rules and models for metal material fracture, it makes lots of troubles for engineering application, because of the lacking of reasonable description of fracture principle and change law. This article discusses some basic problems of applying fractal geometry to fracture research, mainly including sectional fractal characteristics and measurement, the relationship of fractal dimension and fracture toughness, and some kinds of metal fractal models. At last, application of fractal theory in metal fracture is stated.

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 860
Author(s):  
Qingshan Duan ◽  
Jiejie An ◽  
Hanling Mao ◽  
Dongwu Liang ◽  
Hao Li ◽  
...  

The work is intended to summarize the recent progress in the work of fractal theory in packaging material to provide important insights into applied research on fractal in packaging materials. The fractal analysis methods employed for inorganic materials such as metal alloys and ceramics, polymers, and their composites are reviewed from the aspects of fractal feature extraction and fractal dimension calculation methods. Through the fractal dimension of packaging materials and the fractal in their preparation process, the relationship between the fractal characteristic parameters and the properties of packaging materials is discussed. The fractal analysis method can qualitatively and quantitatively characterize the fractal characteristics, microstructure, and properties of a large number of various types of packaging materials. The method of using fractal theory to probe the preparation and properties of packaging materials is universal; the relationship between the properties of packaging materials and fractal dimension will be a critical trend of fractal theory in the research on properties of packaging materials.


Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 892
Author(s):  
Xiangqun Ding ◽  
Xinyu Liang ◽  
Yichao Zhang ◽  
Yanfeng Fang ◽  
Jinghai Zhou ◽  
...  

This study focuses on the relationship between the complexity of pore structure and capillary water absorption of concrete, as well as the connection behavior of concrete in specific directions. In this paper, the water absorption of concrete with different binders was tested during the curing process, and the pore structure of concrete was investigated by mercury intrusion porosimetry (MIP). The results show that the water absorption of concrete with mineral admixtures is lower, mainly due to the existence of reasonable pore structure. The effect of slag on concrete modification is more remarkable comparing with fly ash. In addition, the analysis shows that the pore with different diameters has different fractal characteristics. The connectivity probability and water absorption of unidirectional chaotic pore are linearly correlated with the pore diameter of 50–550 nm, and the correlation coefficient reaches a very significant level, and detailed analysis was undertaken to interpret these results based on fractal theory.


2013 ◽  
Vol 438-439 ◽  
pp. 1108-1111 ◽  
Author(s):  
Ya Bing Huang ◽  
Yan Jun Li ◽  
Tan Jiao

As an important factor that affects the compaction characteristics of the coarse grained fillers in the high speed railway subgrade, the grain composition is characterized by the application of the fractal theory. Several types of the coarse grained fillers were selected for testing and the results indicated that the relationship actually exists between the compaction characteristics and the fractal dimensions. The variation law of the maximum dry density fluctuating with the quality fractal dimension was analyzed and the results were supposed to estimate the compaction characteristics of the coarse grained fillers.


2021 ◽  
Vol 71 (342) ◽  
pp. e250
Author(s):  
L. Guo ◽  
S. Li ◽  
L. Zhong ◽  
L. Guo ◽  
L. Wang ◽  
...  

Owing to complex aspects of cemented sand and gravel (CSG), such as included unscreened aggregates, CSG properties differ from those of ordinary concrete. Fractal theory is introduced to study the effects of aggregate characteristics on CSG properties, quantifying aggregate gradation and shape. Numerical simulation and analyses show that: (1) improved aggregate gradation decreases the gradation fractal dimension and increases the CSG peak stress and elastic modulus; (2) more irregularly shaped aggregates increase the shape fractal dimension and decrease the CSG peak stress and elastic modulus; (3) the relationship quantified between aggregate characteristics and CSG mechanical properties provides a theoretical basis for aggregate allocation in engineering design and construction. Mixing artificial aggregates can improve aggregate gradation but reduces CSG performance. Appropriately blending artificial and on-site aggregates achieves optimal CSG performance; in this study, this is attained using 20% artificial aggregates added under standard gradation.


2011 ◽  
Vol 197-198 ◽  
pp. 662-666
Author(s):  
Qing Jun Zhang ◽  
Wen Ling Mo ◽  
Yuan Liang Li ◽  
Yu Zhu Zhang

The pore in the sinter is an important character. Because of multiphase and asymmetry in the sinter, the structure of the pore is very complex. To study the character of the pore effectively, the method of mercury intrusion porosimetry is applied to measure the pore in the sinter, and the results are dealt with by the fractal theory. The results prove that the pores in the sinter are actually fractal structure when the size of the pores is more than 204.5 nm because their curves in the log-log plot are linear, and some curves qualified with the linearity obviously possess of the segment linearity character. According to the calculation of the fractal D, the relationship of the strength and fractal D will be established.


2014 ◽  
Vol 578-579 ◽  
pp. 1410-1414
Author(s):  
Yan Yan Gao ◽  
Jian Xiong Liu ◽  
Chen Xi Yue ◽  
Xiu Hua Li

Concrete cover thinkness of GFRP to ensure the safety, applicability and durability of the structure is of great significance. Based on studies to 30 the drawing specimens of concrete ,get bond strength of same GFRP diameter,same concrete strength, different concrete cover thinkness. Through the analysis of test data,it is concluded the relationship of the bond strength and the concrete cover thinkness.And basis on the relationship,it is determine the suggestive values on concrete cover thinkness of GFRP.Experimental data and suggestion can provide reference and theoretical basis for the GFRP engineering application and the establishment of the relevant specification.


2012 ◽  
Vol 204-208 ◽  
pp. 3795-3798 ◽  
Author(s):  
Jing Bo Huang ◽  
Xun Yu

Fractal theory was introduced to study the asphalt mixture aggregate gradation which shows visible fractal characteristics, and the fractal dimension of seven different gradations of ATB-25 were calculated quantitatively. Then the rutting test was carried out, and the results show that the fractal dimension of aggregate gradation has a good correlation with the dynamic stability of asphalt mixture. Finally, the paper proposes a multiple linear regression formula which may more accurately predict the high-temperature stability of the asphalt mixture with different gradations.


Fractals ◽  
2021 ◽  
Vol 29 (02) ◽  
pp. 2102001
Author(s):  
LEI WANG ◽  
SHENGWEN TANG

In recent years, the application of fractal theory in construction materials has drawn tremendous attention worldwide. This special issue section containing seven papers publishes the recent advances in the investigation and application of fractal-based approaches implemented in construction materials. The topics covered in this introduction mainly include: (1) the fractal characterization of construction materials from nano- to micro-scales; (2) combining fractals methods with other theoretical, numerical and/or experimental methods to evaluate or predict the macroscopic behavior of construction materials; (3) the relationship of fractal dimension with the macro-properties (i.e. mechanical property, shrinkage behavior, permeability, frost resistance, abrasion resistance, etc.) of construction materials.


Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5404
Author(s):  
Yutao Li ◽  
Yixin Zhao ◽  
Yaodong Jiang ◽  
Bo Zhang ◽  
Honghua Song ◽  
...  

Coal is a complex heterogeneous and anisotropic material conformed with fractal characteristics. The pore and fracture characteristics have important influence on the dynamic disasters including rock burst and gas outburst, however, the relationship between them is not accurately investigated due to inadequate research method. The pore and fracture distribution of coal with different bursting proneness were obtained by comprehensive application of MIP, LTNAD, SEM, and X-ray CT, and then fractal theory and DIC were used to research the pore and fracture characteristics. The result indicated that the modification of MIP result by LTNAD result could effectively eliminate the adverse effect of coal matrix compressibility, exactly reflect the distribution of pore and fracture in coal, and the pore distribution of coal with different bursting proneness were quite different. Gray scale image from SEM and 3D reconstruction technology based on X-ray CT could show the geological structure, fracture structure, and pore structure characteristics of coal. The study of LTNAD, SEM, and X-ray CT showed that these methods complemented each other, the coal had fractal properties, and the fractal dimension value had a positive correlation with the bursting proneness of coal sample.


2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Bingjun Gao ◽  
Xiaohui Chen ◽  
Xiaoping Shi ◽  
Junhua Dong

An important issue in engineering application of the “design by analysis” approach in pressure vessel design is how to decompose an overall stress field obtained by finite element analysis into different stress categories defined in the ASME B&PV Codes III and VIII-2. In many pressure vessel structures, it is difficult to obtain PL+Pb due to the lack of information about primary bending stress. In this paper, a simple approach to derive the primary bending stress from the finite element analysis was proposed with application examples and verifications. According to the relationship of the bending stress and applied loads or the relationship of the bending stress and displacement agreement, it is possible to identify loads causing primary bending stress for typical pressure vessel structures. By applying the load inducing primary bending stress alone and necessary superposition, the primary bending stress and corresponding stress intensity PL+Pb can be determined for vessel design, especially for axisymmetric problems.


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