Hongjun Yu^1,*, Canjie Huang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.1, pp. 1-1, 2024, DOI:10.32604/icces.2024.011454

Abstract A novel and irreversible phase field model accounting for tension-torsion coupling effect and size-effect is constructed in the context of continuum thermodynamics. First, a general framework considering the energy dissipation process influenced by micro and macro force is formulated according to thermodynamically consistent derivation. Next, the framework is specialized by introducing a material parameter called chiral coefficient to characterize the tension-torsion coupling effect within macro force constitutive according to isotropic micropolar elasticity theory. To gain insight of the chiral effect on the fracture behaviors, the analytical solution of uniaxial traction chiral rod is provided based More >

Sihui Tong¹, Boyuan Cao¹, Dongqing Tian², Qinwei Ma¹, Guangyan Liu^1,*, Li Shi², Libin Sun²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.1, pp. 1-1, 2024, DOI:10.32604/icces.2024.010870

Abstract Graphite materials serve critical roles as moderators, reflectors and core structural components in high-temperature gas-cooled nuclear reactors. These materials may experience a variety of loads during the reactor operation, including thermal, radiation, fatigue and dynamic loads, potentially leading to crack initiation and propagation. Consequently, it is imperative to investigate the fracture properties of graphite materials. Currently, there exists a dearth of comprehensive studies on the fracture toughness of graphite materials with varying grain sizes, especially regarding dynamic fracture toughness. This study introduces a novel approach utilizing a digital-image-correlation-based virtual extensometer to analyze crack propagation in… More >

Rajan Aravind^1,2, Sundararajan Natarajan¹, Krishnankutty Jayakumar², Ratna Kumar Annabattula^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.141, No.2, pp. 997-1032, 2024, DOI:10.32604/cmes.2024.053047 - 27 September 2024

Abstract Understanding the probabilistic nature of brittle materials due to inherent dispersions in their mechanical properties is important to assess their reliability and safety for sensitive engineering applications. This is all the more important when elements composed of brittle materials are exposed to dynamic environments, resulting in catastrophic fatigue failures. The authors propose the application of a non-intrusive polynomial chaos expansion method for probabilistic studies on brittle materials undergoing fatigue fracture when geometrical parameters and material properties are random independent variables. Understanding the probabilistic nature of fatigue fracture in brittle materials is crucial for ensuring the… More >

Mingjing Lu^1,2,*, Qin Qian¹, Anhai Zhong¹, Feng Yang¹, Wenjun He¹, Min Li¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.10, pp. 2281-2300, 2024, DOI:10.32604/fdmp.2024.051594 - 23 September 2024

Abstract Continental shale oil reservoirs, characterized by numerous bedding planes and micro-nano scale pores, feature significantly higher stress sensitivity compared to other types of reservoirs. However, research on suitable stress sensitivity characterization models is still limited. In this study, three commonly used stress sensitivity models for shale oil reservoirs were considered, and experiments on representative core samples were conducted. By fitting and comparing the data, the “exponential model” was identified as a characterization model that accurately represents stress sensitivity in continental shale oil reservoirs. To validate the accuracy of the model, a two-phase seepage mathematical model More >

Mingxu Zhang¹, Mingliang Wang², Wei Zhang^3,*

Structural Durability & Health Monitoring, Vol.18, No.5, pp. 599-622, 2024, DOI:10.32604/sdhm.2024.051949 - 19 July 2024

Abstract This paper examines the mechanical behavior of fiber reinforced polymer (FRP)-confined concrete under cyclic compression using the 3D cohesive zone model (CZM). A numerical modeling method was developed, employing zero-thickness cohesive elements to represent the stress-displacement relationship of concrete potential fracture surfaces and FRP-concrete interfaces. Additionally, mixed-mode damage plastic constitutive models were proposed for the concrete potential fracture surfaces and FRP-concrete interface, considering interfacial friction. Furthermore, an anisotropic plastic constitutive model was developed for the FRP composite jacket. The CZM model proposed in this study was validated using experimental data from plain concrete and large More >

Xin Liu^1,*, Kai Yan², Bo Fang³, Xiaoyu Sun³, Daqiang Feng⁴, Li Yin⁵

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.7, pp. 1539-1552, 2024, DOI:10.32604/fdmp.2024.047922 - 23 July 2024

Abstract In response to the complex characteristics of actual low-permeability tight reservoirs, this study develops a meshless-based numerical simulation method for oil-water two-phase flow in these reservoirs, considering complex boundary shapes. Utilizing radial basis function point interpolation, the method approximates shape functions for unknown functions within the nodal influence domain. The shape functions constructed by the aforementioned meshless interpolation method have δ-function properties, which facilitate the handling of essential aspects like the controlled bottom-hole flow pressure in horizontal wells. Moreover, the meshless method offers greater flexibility and freedom compared to grid cell discretization, making it simpler… More >

Xiao Yan^1,2,3, Di Wang^1,2,4, Haitao Yu^1,2,3,5,*

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.3, pp. 3051-3071, 2024, DOI:10.32604/cmes.2024.051832 - 08 July 2024

Abstract The existence of high-density bedding planes is a typical characteristic of shale oil reservoirs. Understanding the behavior of hydraulic fracturing in high-density laminated rocks is significant for promoting shale oil production. In this study, a hydraulic fracturing model considering tensile failure and frictional slip of the bedding planes is established within the framework of the unified pipe-interface element method (UP-IEM). The model developed for simulating the interaction between the hydraulic fracture and the bedding plane is validated by comparison with experimental results. The hydraulic fracturing patterns in sealed and unsealed bedding planes are compared. Additionally,… More >

Liping Zu¹, Yaxun Liu¹, Haoran Zhang¹, Lisheng Liu^2,*, Xin Lai^2,*, Hai Mei²

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.3, pp. 2349-2371, 2024, DOI:10.32604/cmes.2024.050488 - 08 July 2024

Abstract Fracture in ductile materials often occurs in conjunction with plastic deformation. However, in the bond-based peridynamic (BB-PD) theory, the classic mechanical stress is not defined inherently. This makes it difficult to describe plasticity directly using the classical plastic theory. To address the above issue, a unified bond-based peridynamics model was proposed as an effective tool to solve elastoplastic fracture problems. Compared to the existing models, the proposed model directly describes the elastoplastic theory at the bond level without the need for additional calculation means. The results obtained in the context of this model are shown More >

Huiyan Zhao¹, Xuezhong Chen¹, Zhijian Hu^2,*, Man Chen¹, Bo Xiong³, Jianying Yang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.6, pp. 1313-1330, 2024, DOI:10.32604/fdmp.2024.048840 - 27 June 2024

Abstract Using the typical characteristics of multi-layered marine and continental transitional gas reservoirs as a basis, a model is developed to predict the related well production rate. This model relies on the fractal theory of tortuous capillary bundles and can take into account multiple gas flow mechanisms at the micrometer and nanometer scales, as well as the flow characteristics in different types of thin layers (tight sandstone gas, shale gas, and coalbed gas). Moreover, a source-sink function concept and a pressure drop superposition principle are utilized to introduce a coupled flow model in the reservoir. A… More > Graphic Abstract

Yan Liu¹, Tianli Sun², Bencheng Wang^1,*, Yan Feng²

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.6, pp. 1165-1180, 2024, DOI:10.32604/fdmp.2023.041852 - 27 June 2024

Abstract A numerical model of hydraulic fracture propagation is introduced for a representative reservoir (Yuanba continental tight sandstone gas reservoir in Northeast Sichuan). Different parameters are considered, i.e., the interlayer stress difference, the fracturing discharge rate and the fracturing fluid viscosity. The results show that these factors affect the gas and water production by influencing the fracture size. The interlayer stress difference can effectively control the fracture height. The greater the stress difference, the smaller the dimensionless reconstruction volume of the reservoir, while the flowback rate and gas production are lower. A large displacement fracturing construction More >