Numerical Simulation of Fracture Propagation of Heterogeneous Material

2012 ◽  
Vol 170-173 ◽  
pp. 581-584 ◽  
Author(s):  
Ze Qi Zhu ◽  
Qian Sheng ◽  
Xiao Dong Fu
Keyword(s):  
Image Processing ◽  
Numerical Modeling ◽  
Finite Difference ◽  
Failure Process ◽  
Heterogeneous Material ◽  
Modeling Method ◽  
Uniaxial Compression Test ◽  
Fuzzy Clustering Method ◽  
Heterogeneous Rock ◽  
Mineral Components

For the Three Gorges granite, a finite difference software package FLAC was used to study failure process of heterogeneous rock material. Based on mineral components identification results of the granite and fuzzy clustering method, the actual image date was transformed into the finite difference grid by applying image processing techniques. A convenient and efficient two-dimensional numerical modeling method for heterogeneous geomaterials was presented. Then, failure process of the granite were simulated in uniaxial compression test based on experimental strain soft model, and the stress concentration phenomenon was analyzed. The results show that the numerical modeling method based on digital image processing can be used to calculate the mechanical responses of geomaterials by taking their heterogeneities into considerations.

scholarly journals SPH Model for Numerical Test of Heterogeneous Rock-like Material

2020 ◽  
Vol 319 ◽  
pp. 08004
Author(s):  
Chaoqun Sun ◽  
Erlong Song ◽  
Luchen Zhang ◽  
Feng Nan
Keyword(s):  
Acoustic Emission ◽  
Failure Process ◽  
Numerical Test ◽  
Evolutionary Process ◽  
Heterogeneous Material ◽  
Heterogeneous Rock ◽  
Calculation Results ◽  
Sph Model ◽  
Sph Simulation ◽  
Coulomb Criterion

Based on the Smoothed Particles Hydrodynamics (SPH) method, a heterogeneous material numerical model is developed for simulation of fracture process of heterogeneous rock-like material, such as rock. The self-developed SPH program is proposed to analyse the mechanical properties of rock-like materials. In the present program, the combined Mohr-Coulomb criterion is adopted. The deformation of rock-like material under uniaxial compression can be analysed, and the acoustic emission in rock-like material can also be clarified. The calculation results show that the SPH simulation model can be used for numerical test of heterogeneous rock-like material. The process of destruction of rock specimen is evolutionary process. Rock acoustic emission records the brittle failure process of rock-like material.

scholarly journals A Modified SPH Method for Dynamic Failure Simulation of Heterogeneous Material

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
G. W. Ma ◽  
Q. S. Wang ◽  
X. W. Yi ◽  
X. J. Wang
Keyword(s):  
Failure Process ◽  
Damage Model ◽  
Heterogeneous Materials ◽  
Dynamic Strength ◽  
Heterogeneous Material ◽  
Uniaxial Compression Test ◽  
Sph Method ◽  
Failure Patterns ◽  
Splitting Test ◽  
Particle Hydrodynamics

A modified smoothed particle hydrodynamics (SPH) method is applied to simulate the failure process of heterogeneous materials. An elastoplastic damage model based on an extension form of the unified twin shear strength (UTSS) criterion is adopted. Polycrystalline modeling is introduced to generate the artificial microstructure of specimen for the dynamic simulation of Brazilian splitting test and uniaxial compression test. The strain rate effect on the predicted dynamic tensile and compressive strength is discussed. The final failure patterns and the dynamic strength increments demonstrate good agreements with experimental results. It is illustrated that the polycrystalline modeling approach combined with the SPH method is promising to simulate more complex failure process of heterogeneous materials.

scholarly journals Mesoscopic Numerical Simulation of Stratified Rock Failure Using Digital Image Processing

2014 ◽  
Vol 6 ◽  
pp. 106073 ◽  
Author(s):  
Ang Li ◽  
Guo-jian Shao ◽  
Tian-tang Yu ◽  
Jing-bo Su ◽  
Sheng-yong Ding
Keyword(s):  
Image Processing ◽  
Finite Difference ◽  
Digital Image Processing ◽  
Digital Image ◽  
Failure Process ◽  
Region Growing ◽  
Threshold Value ◽  
New Method ◽  
Seeded Region Growing ◽  
Stratified Rock

This paper presents a digital image processing (DIP) based finite difference method (FDM) and makes the first attempt to apply the new method to the failure process of stratified rocks from Chinese Jinping underground carves. In the method, the two-dimensional (2D) inhomogeneity and mesostructures of rock materials are first identified with the DIP technique. And then the binarization image information is used to generate the finite difference grids. Finally, the failure process of stratified rock samples under uniaxial compression condition is simulated by using the FDM. In the DIP, an image segmentation algorithm based on seeded region growing (SRG) is proposed, instead of the traditional threshold value method. And with the new method, we can fully acquire the inhomogeneous distributions and mesostructures of stratified rocks. The simulated macroscopic mechanical behaviors are in good agreement with the laboratory experimental observation. Numerical results show that the proposed DIP based FDM is suitable for the failure analysis of stratified rocks because it can fully take into account the material heterogeneity, and the anisotropy of stratified rocks is also disposed to some extent.

Somatic cell count in buffalo milk using fuzzy clustering and image processing techniques

2021 ◽  
Vol 88 (1) ◽  
pp. 69-72
Author(s):  
Aline Silva Ramos ◽  
Cristiano Hora Fontes ◽  
Adonias Magdiel Ferreira ◽  
Camila Costa Baccili ◽  
Karen Nascimento da Silva ◽  
...  
Keyword(s):  
Image Processing ◽  
Somatic Cell ◽  
Cell Count ◽  
Fuzzy Clustering ◽  
Somatic Cell Count ◽  
Visual Observation ◽  
Buffalo Milk ◽  
Image Processing Techniques ◽  
Fuzzy Clustering Method ◽  
Processing Techniques

AbstractThis research communication presents an automatic method for the counting of somatic cells in buffalo milk, which includes the application of a fuzzy clustering method and image processing techniques (somatic cell count with fuzzy clustering and image processing|, SCCFCI). Somatic cell count (SCC) in milk is the main biomarker for assessing milk quality and it is traditionally performed by exhaustive methods consisting of the visual observation of cells in milk smears through a microscope, which generates uncertainties associated with human interpretation. Unlike other similar works, the proposed method applies the Fuzzy C-Means (FCM) method as a preprocessing step in order to separate the images (objects) of the cells into clusters according to the color intensity. This contributes signficantly to the performance of the subsequent processing steps (thresholding, segmentation and recognition/identification). Two methods of thresholding were evaluated and the Watershed Transform was used for the identification and separation of nearby cells. A detailed statistical analysis of the results showed that the SCCFCI method is able to provide results which are consistent with those obtained by conventional counting. This method therefore represents a viable alternative for quality control in buffalo milk production.

scholarly journals NUMERICAL MODELING AND FULL-SCALE EXPERIMENTS OF GLUED WOODEN STRUCTURES JOINT DESTRUCTION ON CARBON-FIBER DOWEL PINS

2020 ◽  
Vol 16 (2) ◽  
pp. 101-112
Author(s):  
Mikhail Vodiannikov ◽  
Galina Kashevarova ◽  
Danil Starobogatov
Keyword(s):  
Numerical Modeling ◽  
Structural Analysis ◽  
Carbon Fiber ◽  
Structural Parameters ◽  
General Structure ◽  
Failure Process ◽  
Joint Destruction ◽  
Field Tests ◽  
Full Scale ◽  
Glued Laminated Timber

This paper presents the results of numerical modeling and full-scale experiments of the failure process of a glued laminated timber beam with rigid joint in the middle. All the connecting parts are made of carbon fiber. The structural analysis is done with the finite element method (ANSYS software). The nonlinear problem was solved. The contact interaction of the structural elements in the process of deformation and fracture, as well as orthotropy of the wood, the transversely isotropic properties of the plates, and the real diagrams of the deformation of carbon fiber dowel pins were taken into account. The influence of the structural parameters of the joint on the position of the most loaded dowel pin in the joint and the bearing capacity of the general structure are investigated. To verify the structural analysis results, field tests were carried out before destruction by a stepwise increasing load on a personally designed stand. The destruction of the structure occurred according to the forecast of the numerical model as a result of the mutual slip of the glued wood layers and the destruction of the polymer matrix of the glued dowel pins with the beginning of the formation of plastic joints and the formation of cracks in the wood at the junction.

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