Rock is often subjected to fatigue loads in many mining and civil engineering, rock fatigue mechanical behaviors under constant stress amplitude have been widely investigated. Yet the increasing-amplitude fracture mechanical characteristics of rock and the associated damage evolution model are not well understood. In this work, uniaxial increasing-amplitude fatigue loading experiments were conducted

The present paper is aimed to examine the fracture behavior of calcium aluminate cement concrete. A total of 90 notched beams with water-cement ratios (W/C) between 0.3 and 0.55 were selected and subjected to the three-point bending tests. Two methods, i.e. the size effect method (SEM) and the work of fracture method (WFM), were adopted to calculate the fracture parameters for all the mix designs.

Single-crystal silicon is the fundamental building block enabling today’s plethora of integrated electronic components. However, complex mechanical stresses, originating from either direct mechanical loading or thermal cycling, can result in fracture of the constituent silicon, one of the leading causes of semiconductor device failure. Although phenomenological relationships to estimate the fracture

To study the influence of creep recovery on the fracture properties of concrete, the pre-notched specimens were firstly subjected to three-point bending (TPB) loading at 60% peak load (Pmax) over 30 days. Afterwards, the load was removed and the creep recovery tests were performed for 1, 2, 3 and 15 days, respectively. Thereafter, the quasi-static TPB tests were conducted on the creep recovery specimens

The non-invasive monitoring of crack initiation and growth processes within snow, a poro-composite matrix, could be useful to predict the structural failure of a composite material. Present work is a new approach utilizing the non-invasive technique of acoustic emission (AE) to study the ongoing cracking and failures processes within snow beams which is difficult to visualize in real time. The progressive

In this manuscript, the interface crack problem is investigated for a functionally graded coating-substrate structure under steady heat flux. The general thermal-elastic properties of the functionally graded material (FGM) coating are considered. A piecewise-exponential model (PE model) is developed for the thermal fracture problem. In the PE model, the piecewise-exponential function is used to approach

Fatigue failure of metal parts is common in engineering, and the failure mechanisms remain to be studied. The crystal plastic finite element method (CPFEM) was used to study the damage evolution of materials at the crack tip of precracked compact tension (CT) specimen based on the established crystal plasticity constitutive relation which considered the grain size effect and cyclic hardening. The parameters

Underground projects are typically performed in nonpersistent jointed rock masses. Excavation of tunnels or chambers causes crack initiation, propagation and coalescence, resulting in the instability and destruction of surrounding rocks. The failure behaviour of rocks is complicated owing to the interaction between holes and joints. Therefore, understanding the failure characteristics of holes in jointed

Wire and Arc Additive Manufacturing (WAAM) technology offers efficient fabrication of large scale products and is currently being implemented across various industries. In this study, an experimental investigation has been carried out to characterise the mechanical and fracture properties of WAAM components made of ER70S-6 and ER100S-1 metal wires. Microhardness, tensile and fracture toughness tests

Understanding dynamic crack branching and propagation under impact conditions in Functionally Graded Materials (FGMs) is important as engineering components are often subjected to impact loads. Investigation of crack paths may lead to better material and structure designs. Recently, Phase-Field Fracture (PFF) modeling techniques are gaining importance and are shown to provide good predictions of crack

In this study, the mixed mode I/II notch fracture toughness (NFT) of polymeric (PMMA and GPPS) specimens weakened by U- and key-hole notches is assessed experimentally and theoretically. For this aim, first, by performing experiments, the apparent fracture toughness values of cracked polymeric semi-circular bending (SCB) and Brazilian disk (BD) specimens with four different radii are specified. Next

The overarching objective of the paper is to analyze the mixed-mode crack propagation direction angles by molecular dynamics method and to investigate the validity of continuum-based linear elastic fracture mechanics crack growth criteria. For this purpose, an embedded atom potential (EAM) available in LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) molecular dynamics (MD) software

Meso-damage mechanics differs from continuous damage mechanics, which pays more attention to the evolution of meso-structure in materials. It combines physical and mechanical processes to link meso-structure evolution of materials to their macro-mechanical behavior through some average method. The development of meso-damage mechanics provides an alternative method for describing the damage behavior

Bimrocks are a kind of rocks in which blocks are randomly distributed in a matrix. Despite their wide distribution in nature, their significant effects on the failure of rock structures such as slopes, mines and tunnels have been neglected. Bimrocks behave differently than any other rock types as they contain mix of blocks (of different strength, size and distribution volume in matrix) and a matrix

This study reports the coefficients of the crack tip asymptotic field for the semi-circular bend (SCB) specimen made of anisotropic rocks when subjected to pure mode I loading. The finite element over-deterministic method is employed to determine the singular and higher order terms of the crack tip asymptotic field for a wide range of geometry and anisotropy parameters associated with the Mode I SCB

Fatigue crack growth (FCG) is simulated here by node release, which is made when the accumulated plastic strain reaches a critical value. The numerical procedure is very robust, showing a very fast stabilization and independence relatively to the load considered for node release. A critical accumulated plastic strain of 110% was obtained for the 2024-T351 aluminium alloy, comparing the experimental

In recent years, the cohesive zone model (CZM) coupled with linear solid elements has become increasingly popular for the impact fracture analysis of laminated glass. Meanwhile, the computational inefficiency problem accompanied by the method has also been highlighted, where the internal force calculation requires high computational cost. In view of this, this work presents a fracture model combining

This contribution proposes an incremental approach to fatigue life estimate of ductile materials subjected to low cycle fatigue. In this approach, the life prediction is based on the evolution of the internal damage variable of a proposed extension for the Gurson model capable of describing the gradual degradation of the material in function of the number of loading cycles. The extension of the model

An anisotropic, in particular transversal isotropic, thermodynamically consistent material model for unidirectional fiber composite layers at finite strain is proposed. To account for the anisotropy, the concept of structural tensors is used. Tension–compression asymmetric fiber damage as well as an elasto-plastic-damage matrix material are discussed, whereas plasticity and damage are modeled by a

In this work the effect of stress triaxiality on cleavage fracture stress was investigated by means of micromechanical modelling. A unit-cell model was used to determine macroscopic conditions for brittle fracture, in accordance with the slip-induced cleavage fracture model, because of included particle fracture and consequent crack initiation in the matrix. This approach allowed to correlate the critical

The Gurson-Tvergaard-Needleman damage model is implemented in Small Punch (SP) finite element model with the purpose of evaluating the influence of crack initialization and propagation on the SP force–displacement (F-v) curves and the maximum force, Fm, which is used for estimating the Rm. Five materials, significantly different in Rm and ductility are investigated. Numerical calculations are performed

This study presents a theoretical approach to characterize the mesoscopic dynamic fracture behaviors of concrete. Firstly, different fracture behaviors are determined from energy criteria. Secondly, by considering the energy equivalence principle, the Saint-Venant’s principle and the Newton’s laws of motion, an extended self-consistent finite stress model (XSFSM) is established for dynamic fracture

The mode I fracture parameters for an orthotropic body are directly calculated from full-field deformation measurements provided by Digital Image Correlation (DIC). Three complementary and direct approaches are evaluated and compared: (i) the determination of the Stress Intensity Factor (SIF) by fitting the displacement field using the analytical expression proposed by Lekhnitskii; (ii) the determination

This study is aimed at exploring the effect of the lower limit of cyclic stress (LLCS) on the loading and unloading failure process of sandstone. First, cyclic loading and unloading experiments were performed on sandstone samples under different stress paths. Furthermore, the variations of mechanical properties and acoustic emission (AE) signals of samples during cyclic loading and unloading were analyzed

In this study, a novel procedure enabling the computation of the relative displacements (normal δn, shear δss and in-plane δsl) that are needed to evaluate a traction-separation law (TSL) under finite displacement and rotation hypotheses within the framework of interface modelling is investigated. This kind of procedure is required when rigid body motions appear along the interface that links two solids

In elasto-plastic fracture mechanics, the fracture toughness is not a material intrinsic parameter but depends on the constraint level ahead of the crack tip. The accurate determination of the effect of the crack tip constraint on the fracture toughness is very important for the safety assessment of crack-containing structures. In this work, the pipeline steels are selected as the research materials

The mechanical behavior of crack tip under mode I and mixed-mode I-II fatigue loading for commercial pure titanium at negative load ratios are carried out by finite element method in this paper. The effects of maximum fatigue load, load ratio, loading angle and normalized crack length on the mechanical behavior of crack tip are discussed. The change of mechanical behavior of crack tip is analyzed through

Grouting reinforcement is a common way to strengthen fractured rock mass in rock engineering, which will transform the natural open flaws in rock mass into filled flaws. The existence of fillers will change the stress state of the flaws, thus affecting the mechanical properties and cracking behavior of fractured rock mass. In this paper, uniaxial compression experiments were carried out on granite

The influence of orientation on the creep rupture properties of nickel-based single crystal superalloy with a center film hole was carried out at 980 °C and 300 MPa. The mechanisms of creep rupture and microstructural evolution of the specimens were studied through macro- and micro-morphological observations and finite element analysis. The central film hole exhibited the creep-strengthening effect

The results of experimental and numerical analyses concerning the failure mechanisms of S355JR steel are presented. Tests were performed on S355JR steel after three heat treatments at three different temperatures with five specimen geometries that were designed to provide different values of the stress triaxiality and Lode parameter as well as different critical strains and stresses at the onset of

In this paper, the mixed mode problem for a magneto-electro-elastic (MEE) material containing multiple cracks under in-plane magneto-electro-mechanical loads is analyzed. First, the solution to an generalized dislocation is obtained in the infinite MEE plane. The Fourier transform is employed to derive closed-form expressions for the stress, electric displacement and magnetic induction components.

The residual stresses associated with fusion welding processes have recently become a popular issue considering the reliable design of structural components. In a welding problem, it is quite common that fracture is observed to initiate either directly from the welds or from fatigue cracks that develop in the weld’s heat affected zone (HAZ). A recent study has investigated the effects of subsequent

Laminated glass is normally a three-layer sandwiched composite structure, i.e. two glass layers and one PVB interlayer. The discrete element/finite element (DE/FE) coupling approach, which uses DEs and FEs to respectively discretize the glass and PVB layers, has proved to be an effective method for impact failure analysis of laminated glass. However, only one failure pattern, glass cracking, was considered

The purpose of this paper is to investigate the crack growth and fatigue life estimation of the optimized rivet joints in aluminum 2024 sheets numerically and experimentally. For this point, the optimal model is obtained using the Taguchi and finite element method (FEM), with respect to the cost functions and the defined levels for the parameters. The relevant geometrical parameters such as rivets

Bending of micron-scale cantilevers with or without initial notch is simulated by finite element and their fracture is assessed using either the coupled criterion or a cohesive zone model. The fracture toughness and strength of UO2 single grain specimens with several crystal orientations are determined by means of inverse identification based on experimental tests at the micron-scale. Irradiation causes

Fine Granular Area (FGA) and White Etching Cracks (WEC) are two types of fatigue damage phenomena which are characterised by the development of cracks accompanied by a local microstructural transformation. The resulting microstructures share many properties, chiefly a strong reduction in grain size. In this study, the thickness of the transformed zones along the crack formed during FGA and WEC experiments

Based on an experimental result of the literature showing that the crack remains in the grain of its initiation up to about 20% of the lifetime at low cycle fatigue of austenitic stainless steels, the lifetime of a polycrystal made out of these steels undergoing uniaxial isothermal or thermomechanical fatigue from 30 to 340 °C at constant total strain amplitude is calculated. The stresses and strains

This research investigates the toughness of poly(butylene terephthalate) (PBT) nanocomposites, based on mechanical characterizations and subsequent microstructural observations. Montmorillonite (MMT) and nano-precipitated calcium carbonate (NPCC) were selected as nano-reinforcing phases. Notched Izod impact test, tensile test as a quasi-static loading, and mode-I fracture toughness test, were conducted

This paper uses a Fourier transform technique, which uses dislocation density functions, to solve the problem of layered media with finite cracks perpendicular to the interface. This approach reduces the problem to the solution of two coupled integral equations each with a singular kernel which are the solved using Cauchy-Chebyshev polynomials. Two specified loading cases that are symmetric loading

In this paper, we analyse the surface crack growth in the Fibre-Reinforced Polymer (FRP) reinforced steel plates subjected to tension by means of the finite element (FE) method. Following the experimental study, a three-dimensional FE model is developed to evaluate the Stress Intensity Factor (SIF) of the surface crack, and the crack growth rate is calculated by using the Paris’ law. Then the FE model

Applying fracture mechanics approach to spent nuclear fuel (SNF) system reliability investigation is warranted due to the inherent flaws and hydride structures existed in a SNF system after nuclear reactor operation. However, none of the existing fracture toughness data deal with fuel cladding specific geometry or spent fuel material conditions, such as cladding structure with the pellet-inserts and

Two theoretical methods were developed to determine the tensile strength ft of concrete using wedge splitting specimens based on nil-stress intensity factor (nil-SIF) criterion and force equilibrium theory, respectively. With the fracture extreme theory (FET), only experimental peak load of one specimen was needed and did not require the measurement of critical crack mouth opening displacement CMODc

It is important to understand the characteristics of high speed crack in brittle materials under ultra high loading rate forming through impact loading condition, which is important for understanding the impact damage evolution of ceramics and solid explosives. In this paper, a lattice spring model, which can accurately show the mechanical properties of brittle materials, is used to study the evolution

The physical, mechanical, and hydraulic properties of shales with continuous bedding plane vary with bedding orientation significantly. Thus, understanding and predicting crack initiation and propagation in hydraulic fracturing of bedded shale are crucial in terms of reservoir reconstruction. In this paper, a hybrid phase‐field method is proposed to investigate the hydraulic fracturing behaviour in

Discontinuities occur in abundance within a rock mass with or without infill material. The infilled discontinuities as weakness planes containing various materials can play an important role in failure mechanism of rock under triaxial stresses that has not yet been investigated. Three types of infilled discontinuities with friction angles of 32.10, 34.34 and 36.34 degrees were created using three types

Adhesively bonded joints are frequently used in the aviation and automotive industries. Bending appears in the bonded materials as a result of eccentric loading when tensile loading is applied to an adhesively bonded single-lap joint (SLJ) geometry. As a result of this bending, moment effect occurs in the overlap region in the joints joined with the adhesive. This moment effect causes peel stresses

Transverse intralaminar cracks in layers with perpendicular orientation referred to the main loading direction have a significant effect on the apparent ultimate strength of the corresponding composite laminate. This effect stems from the fact that such transverse cracks generally promote the occurrence of other failure mechanisms leading to the specimen collapse in subsequent stages of the loading

The displacement-based methods for the extraction of the Stress Intensity Factors (SIFs) were created decades ago and, since them, they have been used in a wide range of numerical analysis, most of them based on standard 2D Finite Element Method (FEM). Although the accuracy of the SIFs computed by the displacement-based methods generally be inferior compared with the energy release methods, the use

This paper is based on the determination of important fracture parameters for commercially important rubber blends through experimental and finite element modeling methods. Properties of NR/BR blends, which are mainly suitable for tire applications, of various compositions have been tested under tensile load and the result is utilized to determine the suitable hyperelastic material model. A model proposed

In this study, cracked shell-type structures with 3D geometries made of orthotropic materials are considered. Extended Finite Element Method (XFEM) is typically used for analysis of 2D orthotropic plates; however, the available commercial FEM packages like ABAQUS do not offer a solution for cracked orthotropic elements. As a result, authors have developed a programming code in MATLAB software, which

This paper presents a new model for simulating delamination growth in composites in presence of the resistance curve (R-curve) effects. This model is extended from the interface thick level set (ITLS) method which is developed recently. In this approach the common definition of damage in the constitutive relationship of the interface elements is replaced with a new damage definition based on the thick

With the aid of some explicit formulas of the elastic stress fields at the neighborhood of U- and blunt V-shaped notches and also using the Tresca and Von-Mises yield criteria, the plastic zone size at the neighborhood of such notches under mode I loading and plane-stress/strain conditions is determined by extending Irwin’s model. Then, for verifying the analytical results, elastic-plastic finite element

The cyclic plastic response and damage evolution in isothermal high temperature constant strain rate cycling and during in-phase thermomechanical fatigue in superaustenitic Sanicro 25 steel have been studied both with and without introduction of dwells at maximum strain. Fatigue hardening/softening curves and fatigue life curves are reported for all types of fatigue tests. Rapid hardening and a tendency

In order to simplify the fatigue assessment method of the notch stress intensity factors (N-SIFs) and the strain energy density (SED) approach for cruciform welded joints, a simplified notch stress assessment formula was presented based on singular intensity factors asi. It is worth emphasizing that the proposed simple formula is only determined by the distribution of notch stress field and is independent

It is widely accepted that the strength, deformability, and failure behaviors of rock material are strongly influenced by widespread natural fissures. Research focusing on the crack initiation, propagation, and coalescence behavior in fissured rock material is important to ensure the reliability and predictability of rock engineering. However, the types and forms of pre-existing fissures are complex

An important advantage of AM is to create net-shaped components with no need for further surface machining since it is usually very difficult for complex geometries. The effect of surface roughness on fatigue performance of powder bed fusion additively manufactured metals was evaluated in this work. The intrinsic rough surface of metal AM parts that could act like existing surface cracks and significantly

In this study, normalized mode-I stress intensity factors (SIFs) along fronts of three-dimensional tangential surface cracks contained in rotating hollow disks are presented. A wide range of surface cracks with different values of crack aspect ratio, crack depth and radial coordinate along with different geometric parameter settings of the disk are included in the study, yielding a large class of solutions

In this paper, a novel discrete approach based on the independent cover meshless method (ICMM) is presented as a simple yet effective method in pervasive quasi-brittle fracture modeling. In ICMM theory, mesh irrelevant and node-based polynomial meshless approximation functions are defined over independent covers of discrete nodes. One salient feature of ICMM is the unified continuous and discontinuous

Selective laser melting (SLM) is a laser powder-bed fusion process, which produces near-net shaped components with layered microstructures leading to anisotropy in the mechanical properties. The intrinsic process-induced defects, particularly microporosity and lack of fusion, as well as their size and relative orientation with respect to the building direction, affect the fatigue performance of the