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Extended finite element-based cohesive zone method for modeling simultaneous hydraulic fracture height growth in layered reservoirs
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作者 Lei Yang Baixi Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第8期2960-2981,共22页
In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hy... In this study,a fully coupled hydromechanical model within the extended finite element method(XFEM)-based cohesive zone method(CZM)is employed to investigate the simultaneous height growth behavior of multi-cluster hydraulic fractures in layered porous reservoirs with modulus contrast.The coupled hydromechanical model is first verified against an analytical solution and a laboratory experiment.Then,the fracture geometry(e.g.height,aperture,and area)and fluid pressure evolutions of multiple hydraulic fractures placed in a porous reservoir interbedded with alternating stiff and soft layers are investigated using the model.The stress and pore pressure distributions within the layered reservoir during fluid injection are also presented.The simulation results reveal that stress umbrellas are easily to form among multiple hydraulic fractures’tips when propagating in soft layers,which impedes the simultaneous height growth.It is also observed that the impediment effect of soft layer is much more significant in the fractures suppressed by the preferential growth of adjoining fractures.After that,the combined effect of in situ stress ratio and fracturing spacing on the multi-fracture height growth is presented,and the results elucidate the influence of in situ stress ratio on the height growth behavior depending on the fracture spacing.Finally,it is found that the inclusion of soft layers changes the aperture distribution of outmost and interior hydraulic fractures.The results obtained from this study may provide some insights on the understanding of hydraulic fracture height containment observed in filed. 展开更多
关键词 Hydraulic fracturing Layered reservoir Simultaneous height growth In situ stress Fracture spacing extended finite element method(XFEM) Cohesive zone method(CZM)
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Numerical analysis of rock fracturing by gas pressure using the extended finite element method 被引量:8
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作者 Majid Goodarzi Soheil Mohammadi Ahmad Jafari 《Petroleum Science》 SCIE CAS CSCD 2015年第2期304-315,共12页
High energy gas fracturing is a simple approach of applying high pressure gas to stimulate wells by gen- erating several radial cracks without creating any other damages to the wells. In this paper, a numerical algori... High energy gas fracturing is a simple approach of applying high pressure gas to stimulate wells by gen- erating several radial cracks without creating any other damages to the wells. In this paper, a numerical algorithm is proposed to quantitatively simulate propagation of these fractures around a pressurized hole as a quasi-static phenomenon. The gas flow through the cracks is assumed as a one-dimensional transient flow, governed by equations of conservation of mass and momentum. The fractured medium is modeled with the extended finite element method, and the stress intensity factor is calculated by the simple, though sufficiently accurate, displacement ex- trapolation method. To evaluate the proposed algorithm, two field tests are simulated and the unknown parameters are determined through calibration. Sensitivity analyses are performed on the main effective parameters. Considering that the level of uncertainty is very high in these types of engineering problems, the results show a good agreement with the experimental data. They are also consistent with the theory that the final crack length is mainly determined by the gas pressure rather than the initial crack length produced by the stress waves. 展开更多
关键词 Gas fracturing Numerical modeling extended finite element Fracture mechanics
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Real-time embedded software testing method based on extended finite state machine 被引量:6
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作者 Yongfeng Yin Bin Liu Hongying Ni 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2012年第2期276-285,共10页
The reliability of real-time embedded software directly determines the reliability of the whole real-time embedded sys- tem, and the effective software testing is an important way to ensure software quality and reliab... The reliability of real-time embedded software directly determines the reliability of the whole real-time embedded sys- tem, and the effective software testing is an important way to ensure software quality and reliability. Based on the analysis of the characteristics of real-time embedded software, the formal method is introduced into the real-time embedded software testing field and the real-time extended finite state machine (RT-EFSM) model is studied firstly. Then, the time zone division method of real-time embedded system is presented and the definition and description methods of time-constrained transition equivalence class (timeCTEC) are presented. Furthermore, the approaches of the testing sequence and test case generation are put forward. Finally, the proposed method is applied to a typical avionics real- time embedded software testing practice and the examples of the timeCTEC, testing sequences and test cases are given. With the analysis of the testing result, the application verification shows that the proposed method can effectively describe the real-time embedded software state transition characteristics and real-time requirements and play the advantages of the formal methods in accuracy, effectiveness and the automation supporting. Combined with the testing platform, the real-time, closed loop and automated simulation testing for real-time embedded software can be realized effectively. 展开更多
关键词 real-time system real-time embedded software for- mal method extended finite state machine (EFSM) testing se- quence test case.
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Fracture properties of epoxy asphalt mixture based on extended finite element method 被引量:7
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作者 钱振东 胡靖 《Journal of Central South University》 SCIE EI CAS 2012年第11期3335-3341,共7页
Crack is found to be a major distress that affects the performance of the epoxy asphalt pavement.An extended finite element method was proposed for investigating the fracture properties of the epoxy asphalt mixture.Fi... Crack is found to be a major distress that affects the performance of the epoxy asphalt pavement.An extended finite element method was proposed for investigating the fracture properties of the epoxy asphalt mixture.Firstly,the single-edge notched beam test was used to analyze the temperature effect and calculate the material parameters.Then,the mechanical responses were studied using numerical analysis.It is concluded that 5℃ can be selected as the critical temperature that affects the fracture properties,and numerical simulations indicate that crack propagation is found to significantly affect the stress state of the epoxy asphalt mixture.The maximum principal stress at the crack surface exhibits different trends at various temperatures.Numerical solution of stress intensity factor can well meet the theoretical solution,especially when the temperature is lower than 5℃. 展开更多
关键词 epoxy asphalt mixture MICROSTRUCTURE extended finite element method fracture morphology mechanical response
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Evaluation of mixed-mode stress intensity factors by extended finite element method 被引量:3
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作者 茹忠亮 赵洪波 尹顺德 《Journal of Central South University》 SCIE EI CAS 2013年第5期1420-1425,共6页
Extended finite element method (XFEM) implementation of the interaction integral methodology for evaluating the stress intensity factors (SIF) of the mixed-mode crack problem is presented. A discontinuous function... Extended finite element method (XFEM) implementation of the interaction integral methodology for evaluating the stress intensity factors (SIF) of the mixed-mode crack problem is presented. A discontinuous function and the near-tip asymptotic function are added to the classic finite element approximation to model the crack behavior. Two-state integral by the superposition of actual and auxiliary fields is derived to calculate the SIFs. Applications of the proposed technique to the inclined centre crack plate with inclined angle from 0° to 90° and slant edge crack plate with slant angle 45°, 67.5° and 90° are presented, and comparisons are made with closed form solutions. The results show that the proposed method is convenient, accurate and computationallv efficient. 展开更多
关键词 stress intensity factor (SIF) interaction integral method extended finite element method (XFEM)
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Thermoelastic analysis of multiple defects with the extended finite element method 被引量:2
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作者 Honggang Jia Yufeng Nie 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2016年第6期1123-1137,共15页
In this paper, the extended finite element method (XFEM) is adopted to analyze the interaction between a single macroscopic inclusion and a single macroscopic crack as well as that between multiple macroscopic or micr... In this paper, the extended finite element method (XFEM) is adopted to analyze the interaction between a single macroscopic inclusion and a single macroscopic crack as well as that between multiple macroscopic or microscopic defects under thermal/mechanical load. The effects of different shapes of multiple inclusions on the material thermomechanical response are investigated, and the level set method is coupled with XFEM to analyze the interaction of multiple defects. Further, the discretized extended finite element approximations in relation to thermoelastic problems of multiple defects under displacement or temperature field are given. Also, the interfaces of cracks or materials are represented by level set functions, which allow the mesh assignment not to conform to crack or material interfaces. Moreover, stress intensity factors of cracks are obtained by the interaction integral method or the M-integral method, and the stress/strain/stiffness fields are simulated in the case of multiple cracks or multiple inclusions. Finally, some numerical examples are provided to demonstrate the accuracy of our proposed method. 展开更多
关键词 Multiple defects Stress intensity factors extended finite element method (XFEM) THERMOELASTIC
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Simulation of three-dimensional tension-induced cracks based on cracking potential function-incorporated extended finite element method 被引量:1
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作者 WANG Xiang-nan YU Peng +4 位作者 ZHANG Xiang-tao YU Jia-lin HAO Qing-shuo LI Quan-ming YU Yu-zhen 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第1期235-246,共12页
In the finite element method,the numerical simulation of three-dimensional crack propagation is relatively rare,and it is often realized by commercial programs.In addition to the geometric complexity,the determination... In the finite element method,the numerical simulation of three-dimensional crack propagation is relatively rare,and it is often realized by commercial programs.In addition to the geometric complexity,the determination of the cracking direction constitutes a great challenge.In most cases,the local stress state provides the fundamental criterion to judge the presence of cracks and the direction of crack propagation.However,in the case of three-dimensional analysis,the coordination relationship between grid elements due to occurrence of cracks becomes a difficult problem for this method.In this paper,based on the extended finite element method,the stress-related function field is introduced into the calculation domain,and then the boundary value problem of the function is solved.Subsequently,the envelope surface of all propagation directions can be obtained at one time.At last,the possible surface can be selected as the direction of crack development.Based on the aforementioned procedure,such method greatly reduces the programming complexity of tracking the crack propagation.As a suitable method for simulating tension-induced failure,it can simulate multiple cracks simultaneously. 展开更多
关键词 extended finite element method CRACK three-dimensional calculation cracking potential function tensile failure
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Cracking Propagation of Hardening Concrete Based on the Extended Finite Element Method 被引量:2
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作者 朱振泱 CHEN Weimin ZHANG Guoxin 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2017年第5期1132-1139,共8页
Self-deformation cracking is the cracking caused by thermal deformation, autogenous volume deformation or shrinkage deformation. In this paper, an extended finite element calculation method was deduced for concrete cr... Self-deformation cracking is the cracking caused by thermal deformation, autogenous volume deformation or shrinkage deformation. In this paper, an extended finite element calculation method was deduced for concrete crack propagation under a constant hydration and hardening condition during the construction period, and a corresponding programming code was developed. The experimental investigation shows that initial crack propagation caused by self-deformation loads can be analyzed by this program. This improved algorithm was a preliminary application of the XFEM to the problem of the concrete self-deformation cracking during the hydration and hardening period. However, room for improvement exists for this algorithm in terms of matching calculation programs with mass concrete temperature fields containing cooling pipes and the influence of creep or damage on crack propagation. 展开更多
关键词 concrete crack self-deformation loads extended finite element method
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Mesoscopic characterization and modeling of microcracking in cementitious materials by the extended finite element method
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作者 Junjie Huang Mingxiang Chen Jian Sun 《Theoretical & Applied Mechanics Letters》 CAS 2014年第4期1-11,共11页
This study develops a mesoscopic framework and methodology for the modeling of microcracks in concrete. A new algorithm is first proposed for the generation of random concrete meso-structure including microcracks and ... This study develops a mesoscopic framework and methodology for the modeling of microcracks in concrete. A new algorithm is first proposed for the generation of random concrete meso-structure including microcracks and then coupled with the extended finite element method to simulate the heterogeneities and discontinuities present in the meso-structure of concrete. The proposed procedure is verified and exemplified by a series of numerical simulations. The simulation results show that microcracks can exert considerable impact on the fracture performance of concrete. More broadly, this work provides valuable insight into the initiation and propagation mechanism of microcracks in concrete and helps to foster a better understanding of the micro-mechanical behavior of cementitious materials. 展开更多
关键词 MICROCRACKS extended finite element method mesoscopic modeling CONCRETE
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Modeling crack in viscoelastic media using the extended finite element method 被引量:2
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作者 YU TianTang REN QingWen 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第6期1599-1606,共8页
In this paper,the problem of modeling crack in 2D viscoelastic media is studied using the extended finite element method.The paper focuses on the definition of enrichment functions suitable for cracks assessment in vi... In this paper,the problem of modeling crack in 2D viscoelastic media is studied using the extended finite element method.The paper focuses on the definition of enrichment functions suitable for cracks assessment in viscoelastic media and the generalized domain integrals used in the determination of crack tip parameters.The opening mode and mixed mode solutions of crack tip fracture problems in viscoelastic media are also undertaken.The results obtained by the proposed method show good agreement with the analytical methods and provide reasonable background information to enhance the modeling of crack growth in viscoelastic media. 展开更多
关键词 viscoelastic media extended finite element method CRACK crack tip parameters
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OPTIMAL QUADRATIC NITSCHE EXTENDED FINITE ELEMENT METHOD FOR INTERFACE PROBLEM OF DIFFUSION EQUATION 被引量:1
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作者 Fei Wang Shuo Zhang 《Journal of Computational Mathematics》 SCIE CSCD 2018年第5期693-717,共25页
In this paper, we study Nitsche extended finite element method (XFEM) for the inter- face problem of a two dimensional diffusion equation. Specifically, we study the quadratic XFEM scheme on some shape-regular famil... In this paper, we study Nitsche extended finite element method (XFEM) for the inter- face problem of a two dimensional diffusion equation. Specifically, we study the quadratic XFEM scheme on some shape-regular family of grids and prove the optimal convergence rate of the scheme with respect to the mesh size. Main efforts are devoted onto classifying the cases of intersection between the elements and the interface and prove a weighted trace inequality for the extended finite element functions needed, and the general framework of analysing XFEM c^n be implemented then. 展开更多
关键词 Interface problems extended finite element methods Error estimates Nitsche's scheme Quadratic element.
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Extended finite element methods for optimal control problems governed by Poisson equation in non-convex domains 被引量:1
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作者 Tao Wang Chaochao Yang Xiaoping Xie 《Science China Mathematics》 SCIE CSCD 2021年第8期1917-1934,共18页
This paper analyzes two extended finite element methods(XFEMs)for linear quadratic optimal control problems governed by Poisson equation in non-convex domains.We follow the variational discretization concept to discre... This paper analyzes two extended finite element methods(XFEMs)for linear quadratic optimal control problems governed by Poisson equation in non-convex domains.We follow the variational discretization concept to discretize the continuous problems,and apply an XFEM with a cut-off function and a classic XFEM with a fixed enrichment area to discretize the state and co-state equations.Optimal error estimates are derived for the state,co-state and control.Numerical results confirm our theoretical results. 展开更多
关键词 extended finite element method optimal control non-convex domain variational discretization concept
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Numerical Study of Quasi-Static Crack Growth Problems Based on Extended Finite Element Method 被引量:1
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作者 郑安兴 罗先启 《Journal of Shanghai Jiaotong university(Science)》 EI 2014年第6期736-746,共11页
The extended finite element method(XFEM) is a numerical method for modeling discontinuities within a classical finite element framework. Based on the algorithm of XFEM, the major factors such as integral domain factor... The extended finite element method(XFEM) is a numerical method for modeling discontinuities within a classical finite element framework. Based on the algorithm of XFEM, the major factors such as integral domain factor and mesh density which all influence the calculation accuracy of stress intensity factor(SIF) are discussed,and the proper parameters to calculate the SIF are given. The results from the case analysis demonstrate that the crack path is the most sensitive to the crack growth increment size, and the crack path is not mesh-sensitive. A reanalysis method for the XFEM has been introduced. The example presented shows that there is a significantly reduced computational cost for each iteration of crack growth achieved by using the reanalysis method and the reanalysis approach has increasing benefits as the mesh density increases or the value of crack growth increments size decreases. 展开更多
关键词 extended finite element method(XFEM) stress intensity factor(SIF) CRACK level set numerical methods
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Study on interaction between induced and natural fractures by extended finite element method
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作者 DanDan Xu ZhanLi Liu +2 位作者 Zhuo Zhuang QingLei Zeng Tao Wang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2017年第2期24-37,共14页
Fracking is one of the kernel technologies in the remarkable shale gas revolution. The extended finite element method is used in this paper to numerically investigate the interaction between hydraulic and natural frac... Fracking is one of the kernel technologies in the remarkable shale gas revolution. The extended finite element method is used in this paper to numerically investigate the interaction between hydraulic and natural fractures, which is an important issue of the enigmatic fracture network formation in fracking. The criteria which control the opening of natural fracture and crossing of hydraulic fracture are tentatively presented. Influence factors on the interaction process are systematically analyzed, which include the approach angle, anisotropy of in-situ stress and fluid pressure profile. 展开更多
关键词 hydraulic fracturing natural fracture interaction criterion fluid pressure extended finite element method
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Recent advances in the extended finite element method (XFEM) and isogeometric analysis (IGA)
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作者 DanDan Xu ZhanLi Liu Zhuo Zhuang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2016年第12期80-81,共2页
The finite element method (FEM) is one of the most popular and efficient methods for computational modeling in scien- tific research and engineering . To expand its application to more complex problems, lots of new ... The finite element method (FEM) is one of the most popular and efficient methods for computational modeling in scien- tific research and engineering . To expand its application to more complex problems, lots of new FEM-based methods have been developed in recent decades. 展开更多
关键词 XFEM IGA Recent advances in the extended finite element method and isogeometric analysis
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Numerical simulation of loading edge cracks by edge impact using the extended finite element method
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作者 Qinghua Meng Zhenqing Wang 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2015年第2期156-167,共12页
The extended finite element method is used to analyze a plate with two parallel edge cracks impacted by a cylindrical projectile. The influence of the impact speed, crack length, plate thickness and notch tip radius o... The extended finite element method is used to analyze a plate with two parallel edge cracks impacted by a cylindrical projectile. The influence of the impact speed, crack length, plate thickness and notch tip radius on the crack initiation and propagation is studied. Dynamics equations are solved by an implicit time integration scheme which is unconditionally stable. Very good agreement is achieved between numerical predictions and experimental results. The critical velocity of the crack initiation under different conditions is examined. The influence of the crack length is greater than that of the impact speed, plate thickness and notch tip radius. 展开更多
关键词 extended finite element method crack propagation dynamic impact implicit dy- namics
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Concurrent fatigue crack growth simulation using extended finite element method
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作者 Zizi LU Yongming LIU 《Frontiers of Structural and Civil Engineering》 SCIE EI 2010年第3期339-347,共9页
In this paper,a concurrent simulation framework for fatigue crack growth analysis is proposed using a novel small time scale model for fatigue mechanism analysis and the extended finite element method(X-FEM)for fatigu... In this paper,a concurrent simulation framework for fatigue crack growth analysis is proposed using a novel small time scale model for fatigue mechanism analysis and the extended finite element method(X-FEM)for fatigue crack growth simulation.The proposed small time scale fatigue model does not require the cycle counting as those using the classical fatigue analysis methods and can be performed concurrently with structural/mechanical analysis.The X-FEM greatly facilitates crack growth simulation without remeshing requirements ahead of the crack tip as in the classical finite element method.The basic concept and theory of X-FEM was briefly introduced and numerical predictions of stress intensity factors are verified with reference solutions under both uniaxial and multiaxial loadings.The small time scale fatigue model is integrated into the numerical simulation algorithm for concurrent fatigue crack growth analysis.Model predictions are compared with available experimental observations for model validation. 展开更多
关键词 small time scale model extended finite element method(X-FEM) crack growth MULTIAXIAL
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Extended multiscale finite element method for mechanical analysis of heterogeneous materials 被引量:5
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作者 Hong-Wu Zhang·Jing-Kai Wu·Jun L·Zhen-Dong Fu State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology,Dalian 116024,China 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2010年第6期899-920,共22页
An extended multiscale finite element method (EMsFEM) is developed for solving the mechanical problems of heterogeneous materials in elasticity.The underlying idea of the method is to construct numerically the multi... An extended multiscale finite element method (EMsFEM) is developed for solving the mechanical problems of heterogeneous materials in elasticity.The underlying idea of the method is to construct numerically the multiscale base functions to capture the small-scale features of the coarse elements in the multiscale finite element analysis.On the basis of our existing work for periodic truss materials, the construction methods of the base functions for continuum heterogeneous materials are systematically introduced. Numerical experiments show that the choice of boundary conditions for the construction of the base functions has a big influence on the accuracy of the multiscale solutions, thus,different kinds of boundary conditions are proposed. The efficiency and accuracy of the developed method are validated and the results with different boundary conditions are verified through extensive numerical examples with both periodic and random heterogeneous micro-structures.Also, a consistency test of the method is performed numerically. The results show that the EMsFEM can effectively obtain the macro response of the heterogeneous structures as well as the response in micro-scale,especially under the periodic boundary conditions. 展开更多
关键词 extended multiscale finite element method Heterogeneous material Base function Downscaling computation
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Factors Influencing Fracture Propagation in Collaborative Fracturing ofMultiple HorizontalWells
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作者 Diguang Gong Junbin Chen +1 位作者 Cheng Cheng Yuanyuan Kou 《Energy Engineering》 EI 2024年第2期425-437,共13页
Horizontal well-stimulation is the key to unconventional resource exploration and development.The development mode of the well plant helps increase the stimulated reservoir volume.Nevertheless,fracture interference be... Horizontal well-stimulation is the key to unconventional resource exploration and development.The development mode of the well plant helps increase the stimulated reservoir volume.Nevertheless,fracture interference between wells reduces the fracturing effect.Here,a 2D hydro-mechanical coupling model describing hydraulic fracture(HF)propagation is established with the extended finite element method,and the effects of several factors on HF propagation during multiple wells fracturing are analyzed.The results show that with an increase in elastic modulus,horizontal principal stress difference and injection fluid displacement,the total fracture area and the reservoir stimulation efficiency are both improved in all three fracturing technologies.After a comparison of the three technologies,the method of improved zipper fracturing is proposed,which avoids mutual interference between HFs,and the reservoir stimulation effect is improved significantly.The study provides guidance for optimizing the fracturing technology of multiple horizontal wells. 展开更多
关键词 Multi-well fracturing inter-fracture interference hydraulic fracturing hydro-mechanical coupling extended finite element horizontal well
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基于EFSM的智能车间制造系统生产物流建模与仿真 被引量:1
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作者 李柳臻 金超 +1 位作者 林廷宇 朱耀琴 《系统仿真学报》 CAS CSCD 北大核心 2023年第12期2655-2668,共14页
制造业的生产物流方式处于不断变革中,对其建模仿真可为制造系统规划设计、分析及改造提供决策支持。依“人-机-物-环-法”分类给出了智能车间制造系统中实体元素的描述,结合EFSM(extended finite state machine)和组件化建模思想,建立... 制造业的生产物流方式处于不断变革中,对其建模仿真可为制造系统规划设计、分析及改造提供决策支持。依“人-机-物-环-法”分类给出了智能车间制造系统中实体元素的描述,结合EFSM(extended finite state machine)和组件化建模思想,建立了生产和物流组件化EFSM模型;阐述了智能车间多作业生产的建模过程以及组件模型实例化方法;通过EFSM-DEVS(discrete event system specification)模型自动转换及DEVS引擎完成了仿真运行。仿真结果表明:该方法所建立的模型更符合车间实际状况,适用性更广;组件化建模思想能构造更具扩展性的软件;建模及仿真运行的3D可视化使软件直观性更好,其仿真结果与AnyLogic保持一致。 展开更多
关键词 生产物流建模与仿真 EFSM(extended finite state machine) 组件化建模 DEVS(discrete event system specification) 多作业建模
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