Abstract Mode I opening and mixed-mode I-II fracture experiments were performed with a homogeneous, fine grained sandstone using the three-point bending test. Specimens were notched at various lengths and positions of the beam edge to produce the desired loading condition. A micropolar peridynamic model was used to simulate the fracture initiation and propagation process. The analytical implicit formulation was derived by defining a specific microelastic energy density function for micropolar non-local lattices, which depends on three deformation parameters: bond stretch, bond shear deformation accounting for the rotational degrees of freedom, and the particle’s relative rotation. The micropolar non-local lattice model is capable of handling a variable Poisson’s ratio, and is suitable for modelling the mechanical behavior of Cauchy isotropic solids subjected to non-homogeneous deformation fields and fracture. A preliminary analysis on a smooth boundary specimen was performed in order to validate the results obtained with the conceived peridynamic model adopting irregular discretizations. The failure process in notched sandstone specimens was simulated numerically in quasi-static conditions. Numerical results were compared with experimental data obtained from electronic speckle pattern interferometry (ESPI) tests, which were used to quantify and detect the fracture phenomena. Due to the intrinsic features of peridynamic theory, realistic crack patterns and crack initiation angles were obtained from the numerical simulations.
#1Vito Diana(Polytechnic University of Milan)H-Index: 6
#2Siro Casolo(Polytechnic University of Milan)H-Index: 19
Abstract An original full orthotropic model for in-plane linear elasticity is proposed in the micropolar peridynamic analysis framework. The analytical formulation is derived from the definition of a specific microelastic energy function for micropolar nonlocal lattices which allows to obtain, for the first time, an orthotropic bond-based model characterized by four independent elastic moduli. An important feature of the model is that the bond properties, i.e. the elastic constants, are continuo...
Last. Miaomiao Kou(Chongqing University)H-Index: 8
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A 3-D conjugated bond-pair-based peridynamic model is developed to comprehensively investigate failure characteristics of rock-like materials with intermittent fissures in the compressive-shear loading tests. Rock-like specimens containing one single central fissure are first simulated. Numerical results indicate that the 3-D conjugated bond-pair-based peridynamic model can faithfully reproduce failure characteristics of rock-like materials under compressive-shear loads. Then, the failure charac...
Last. Ugo Galvanetto(UNIPD: University of Padua)H-Index: 28
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Abstract The static solution of crack propagation problems can be an efficient way to find both the failure load of a structure and the shape of the crack pattern. The paper introduces two new implicit static solution procedures to study crack propagation problems by adopting a Peridynamic-based numerical tool, and compares them with the Sequentially Linear Analysis. We discretize the structures in space by adopting a coupled FEM–PD approach, which exploits the flexibility of FEM to reduce the o...
#1Vito Diana(Polytechnic University of Milan)H-Index: 6
#2Siro Casolo(Polytechnic University of Milan)H-Index: 19
Abstract A generalized micropolar bond-based Peridynamic model with shear deformability for linear and non-linear problems is proposed. The analytical implicit formulation is derived from the definition of a specific microelastic energy function for micropolar nonlocal lattices, giving particular attention to numerical implementation aspects of the model. We investigate the effectiveness of this formulation, empathizing the importance of considering particle’s rotations in enriched bond-based pe...
#2Vito Diana(Polytechnic University of Milan)H-Index: 6
Last. Siro Casolo(Polytechnic University of Milan)H-Index: 19
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A static meshfree implementation of the bond-based peridynamics formulation for linearly elastic solids is applied to the study of the transition from local to nonlocal behavior of the stress and displacement fields in the vicinity of a crack front and other sources of stress concentration. The long-range nature of the interactions between material points that is intrinsic to and can be modulated within peridynamics enables the smooth transition from the square-root singular stress fields predic...
Last. Ugo Galvanetto(UNIPD: University of Padua)H-Index: 28
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Abstract The standard way of implementing Peridynamics is a meshfree approach which uses a uniform discretization. This is inefficient when a very dense grid spacing for a localized area is required. In this paper, a radically new strategy to couple grids with different spacing is put forward. It is free of ghost forces in static cases and spurious waves in dynamic problems can be controlled and made negligible thanks to proper discretization. There is no loss of volume due to non-uniform discre...
#1Dong Yang(CityU: City University of Hong Kong)H-Index: 4
#2Wei Dong(DUT: Dalian University of Technology)H-Index: 10
Last. Xiaoqiao He(CityU: City University of Hong Kong)H-Index: 52
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Abstract A new damage model is proposed in the bond-based peridynamics (BBPD) frame to quantitatively investigate mode-I crack propagation in concrete, which is established based on the pattern of bilinear softening curve commonly used in the discrete cohesive zone model (CZM). This new damage model can be obtained completely based on material properties, that is, once experimental bilinear softening curve, the uniaxial tensile strength, the elastic modulus and fracture energy of concrete are gi...
#1Q. V. Le(NU: University of Nebraska–Lincoln)H-Index: 11
#2Florin Bobaru(NU: University of Nebraska–Lincoln)H-Index: 32
Peridynamic models are derived by assuming that a material point is located in the bulk. Near a surface or boundary, material points do not have a full non-local neighborhood. This leads to effective material properties near the surface of a peridynamic model to be slightly different from those in the bulk. A number of methods/algorithms have been proposed recently for correcting this peridynamic surface effect. In this study, we investigate the efficacy and computational cost of peridynamic sur...
#1Siro Casolo(Polytechnic University of Milan)H-Index: 19
#2Vito Diana(Polytechnic University of Milan)H-Index: 6
Abstract The failure of a laminated glass beam is investigated by two full discrete numerical approaches: a Rigid Body-Spring Model (RBSM) and a mesh-free numerical method arising from bond-based Peridynamics (PD). The brittle nature of the failure has been modelled and investigated by exploiting the discrete nature of these models, and specifically the PD which allows the bond/spring strengths to be explicitly related with the size and orientation of the defects in the structure. Strength value...
Abstract The lattice model is a discrete model that is typically used to simulate the fracture process of brittle materials. This review summarizes the main achievements during the development history of the state-of-the-art lattice model during the past 80 years from the theory and application viewpoints. It is found that the classical lattice spring model (LSM) can only simulate a fixed Poisson’s ratio. This problem has been partially or fully solved in developed versions of novel lattice mode...
Abstract A viscoelastic micropolar peridynamic (VMPD) model is proposed to describe the nonlinear deformation and fracture behaviors of quasi-brittle materials considering loading-rate effects. The governing equations of bonds connecting material points are reformulated by introducing the definition of bond deformation rates . Two peridynamic parameters, corresponding to the normal stiffness and the tangential stiffness of the bond, respectively, are introduced to ensure that the strain energy o...
#1Yiming Zhang(HEBUT: Hebei University of Technology)H-Index: 11
#2Xueqing Yang(HEBUT: Hebei University of Technology)
Last. Xiaoying Zhuang(Leibniz University of Hanover)H-Index: 55
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Abstract Peridynamic models typically adopt regular point distributions and unified horizons, limiting their flexibility and engineering applicability. In this work, a micropolar peridynamics approach with a nonunified horizon (NHPD) is proposed. This approach is implemented in a conventional finite element framework using element-based discretization. Through modification of the dual-horizon approach in the preprocessing element, a point-dependent horizon and nonunified beam-like bonds are buil...
Peridynamic (PD) models using the equation of motion in the integral form are applied to describe the failure and damage of materials. At present, the most commonly used volume correction algorithms (VCAs) cannot accurately calculate the volume of the intersecting region between a PD point and its neighbouring cells, particularly for the non-uniform discrete regions, which decreases the accuracy of the PD models. In this study, a new precise VCA is proposed to accurately calculate the volumes of...
Abstract In this paper, a novel hybrid FEM and Peridynamic modeling approach proposed in Ni et al. (2020) is used to predict the dynamic solution of hydro-mechanical coupled problems. A modified staggered solution algorithm is adopted to solve the coupled system. A one-dimensional dynamic consolidation problem is solved first to validate the hybrid modeling approach, and both δ -convergence and m r -convergence studies are carried out to determine appropriate discretization parameters for the hy...
Last. Xinyan Peng(PolyU: Hong Kong Polytechnic University)H-Index: 1
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Abstract Crack propagation is a very important research subject within the field of rock mechanics. In this study, a J-integral based Maximum Circumferential Tensile Stress theory was applied to the conventional Discontinuous Deformation Analysis (DDA) Method for simulating crack propagation. First, according to the relevant theories of fracture mechanics, a crack propagation theory suitable for DDA was derived by calculating J-integral in DDA simulation. Then, the crack propagation algorithm wa...
Last. Shaofan Li(University of California, Berkeley)H-Index: 53
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Abstract In this paper, we present two non-local mechanics models of recycled coarse aggregate (RCA) concrete based on peridynamics modeling and simulation, i.e. RCA model 1 and RCA model 2. The recycled coarse aggregate concrete is a heterogeneous composite that has five different phases including natural coarse aggregate, old interfacial transition zone (ITZ), old cement mortar, new ITZ, and new cement mortar. The sizes of the grains of the multi-level structured RCA are randomly generated by ...
Last. J. N. Reddy(A&M: Texas A&M University)H-Index: 122
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In this work, a thermodynamically consistent three-dimensional (3D) small strain-based theory to describe the deformation and fracture in quasi-brittle and brittle elastic solids is presented. The description of fracture at a material point resembles the microplane fracture approach developed by Bažant et al. (J Eng Mech 126(9):944–953, 2000, J Eng Mech 122(3): 245–254, 1996), but the present theory has the following novel features: (a) a probabilistic description of fracture propagation is used...
Last. Hongzhi Zhang(SDU: Shandong University)H-Index: 13
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Abstract Peridynamics (PD) model is a nonlocal theory to describe the formation of discontinuities, e.g., cracks and fractures due to deformations in the displacement field. The current study aims at implementing the Peridynamics theory on the fracture performance modelling of mortar at the meso-scale. For this purpose, a computational uniaxial tension test was performed on a multi-phase virtual specimen consisting of sand, hydrated cement paste and air voids. The mechanical properties of each p...
Most peridynamics models adopt regular point distribution and unified horizon, limiting their flexibility and engineering applications. In this work, a micropolar peridynamics approach with non-unified horizon (NHPD) is proposed. This approach is implemented in a conventional finite element framework, using element-based discretization. By modifying the dual horizon approach into the pre-processing part, point dependent horizon and non-unified beam-like bonds are built. By implementing a domain ...
Prediction of rock fracture is essential to understand the rock failure mechanism. The three-point bending test has been one of the most popular experiments for the determination of rock fracture parameters. However, the crack initiation and propagation of rock beam with the center notch and offset notch have not been fully understood. This paper develops a numerical method for modelling the notched beam cracking based on nonlocal extended finite element method (i.e., XFEM) and mixed mode rock f...