Determination of material properties on creep crack initiation (CCI) and creep crack growth (CCG) using small punch tests is still a virgin field to be exploited. Spanish and Czech researchers have carried out pioneering work and put forward an approach to correlate the notched specimen with the standard CT specimen. The advantage is that, the formulas of C*-integral for CT specimen are available and

The main aim of the present paper is to propose and validate a new and simple diagram able to explain the effect of geometrical variations in orthotropic solids under static loads. The derived approach accounts for the effect of the local geometry of the notch as well as for the relevant material properties and highlights the parameters drawing the demarcation line from notch insensitivity, incomplete

Shot peening (SP) is frequently used as a palliative measure against metal fatigue in many engineering components. The performance of this surface treatment depends on different factors including the material, shape and loading conditions of the component, as well as process parameters. Fatigue improvement due to SP depends to a great extent upon the in-depth compressive residual stress profile produced

The global stress field function of an infinite plate with a closed inclined crack under uniaxial compression is presented, then the stress field at the crack tip is obtained, namely the formulae of KI, KII and T-stress are obtained. A new maximum tangential strain (MTSN) criterion is proposed to predict the initiation of the crack under compression by considering singular and non-singular terms based

Proper understanding of the fracture mechanism of lightweight concrete (LWC) after exposure to high temperatures has a significant role in LWC proportioning design which provides a better comprehension of the structural behavior during a fire event. In this study, the effect of high temperatures (250, 500, and 750 °C) on the fracture parameters of LWC and its brittleness compared to normal-weight concrete

The fracture of layered rocks subjected to tensile stress is involved in various subsurface energy-related activities. Many studies have numerically investigated the fracture evolution behaviour and Brazilian tensile strength (BTS) of layered rock in Brazilian tests. However, the fracture mechanism of layered rocks, especially those with interbedded hard-soft layers, is still not well understood. This

In this paper, the crack propagation behavior of a polymethyl methacrylate plate with double holes under explosive load is investigated. The propagation process of the explosion crack is recorded using a new digital laser dynamic caustics system, in which a high-speed camera and the explosion loading are employed. Firstly, the interaction process between the explosion stress wave and the empty hole

Fracturing behavior of rock is significantly affected by water. To study the influence of water on the critical values of stress intensity factors (the SIFc, including KIf and KIIf) corresponding to the onset of fracture of rocks, edge-cracked semicircular bend (SCB) testing was performed on sandstone specimens (collected at a site in Linyi City, Shandong Province, China) with different water contents

In this paper we study the application of the method of fundamental solutions (MFS) to interface crack analysis in linear elastic bimaterial fracture mechanics. Such problem presents some modelling difficulties because of the oscillatory behavior of the local asymptotic fields in the neighborhood of the interface crack-tip. The present approach is based on the combination of the classical MFS approximation

In this study, a two-dimensional peridynamic contact model is proposed to model the propagation of frictional crack within the peridynamic framework. Compared with traditional numerical method in peridynamics, no additional algorithm is needed for implementing the contact constraint. The geometry of the crack can be easily described by the rupture of bond without any extra enrichment functions. In

The PeriDynamics (PD) model of material fracture can simulate the nucleation and propagation of cracks naturally with a simple bond breakage criterion. Combined with its advantages in multi-scale, the crack characteristics of concrete can be simulated from micro-scale. Therefore, the micro-calculation model of concrete was established by the spherical growth model based on the MATLAB-ABAQUS co-simulation

The present study, deals with fracture behavior of adhesively bonded 3D-printed joints. Polyethylene terephthalate glycol (PETG) is used to print standard specimens with different printing parameters (raster angle, raster width, and layer thickness) using fused deposition modeling (FDM) process. Moreover, adhesive layer with different thicknesses is employed to determine effects of adhesive layer thickness

The aim of this research was the development and application of the following structural strain approaches for predicting the low-cycle fatigue life of AA 5083 welded joints: Finite Element equivalent structural strain approach and Digital Image Correlation equivalent structural strain approach. The first one was already applied for the low-cycle fatigue life prediction of welded joints, while the

In this study, the accuracy and generality of stress calculation for a plate containing double holes via Schwarz alternating method was investigated. The original Schwarz alternating method with inverse mapping function shows a good performance in terms of the stress solution for a plate containing two arched holes. However, for a plate containing two holes with corners, evitable error may be produced

In this work, the possibility to use elemental quantities, computed from non-regular coarse meshes, to assess Notch Stress Intensity Factors at pointed V-notches (with a notch opening angle different from zero) is explored. To this end, the analytical expressions for the Energy Density and averaged stresses over a four sided finite element close to the notch tip are firstly derived, based on Williams

The current paper presents the application of three-dimensional (3D) constraint-based fracture mechanics for the determination of R-curves (J-R curves and CTOD-R curves) of thermal aged 16MND5 bainitic forging steel. First, the fracture toughness test results of 16MND5 steel using different sized clamped single edge notched tension (SENT) specimens under various thermal aging durations were summarized

Rock fracture toughness is an important parameter for the engineering geological design. In this present study, chevron straight-notched semi-circular bend (CSNSCB) specimens with wide-flat liner chevron ligament (Type-A) and long-narrow liner chevron ligament (Type-B) were designed and prepared using wire cutting method. Mode-I fracture toughness KIC values and dimensionless stress intensity factor

In this study, the dynamic stress intensity factors (DSIFs) at the tip of several cracks located at the interface between two half-planes made of functionally graded materials (FGMs) are calculated using the Distributed Dislocation technique (DDT). In this paper, the in-plane time-harmonic loading is considered and it is assumed that the properties of the FGMs follow the law of exponential function

In this paper, the influence of support type on mode II fracture experiments of asphalt concrete is investigated. The experiments were performed using three various types of supports i.e. roller, roller-in-groove and fixed supports, employed in semi-circular bend (SCB) testing fixture, under pure mode II fracture loading. These experiments were conducted at five different temperatures including −20

This paper presents a damaging stress intensity function ΔKd for analyzing R-ratio effects on fatigue crack growth (FCG) in metallic materials under constant amplitude loading. The proposed formulation is based on the sum of strain and complementary energy and its role in FCG rate behavior in threshold and Paris region at R-ratios ranging from −2 to 0.97. It doesn’t invoke a crack closure assumption

The Charpy impact test is often used to qualify the structural materials used for the fabrication of industrial components, in particular steel-based components. This relatively simple test used for more than a century was originally designed to contribute to ensure steel quality. Later, it was used to determine the so-called ductile-to-brittle transition temperature (DBTT) to characterize the fracture

Home-synthesized carbon aerogels were used as reinforcements for epoxy nanocomposites in different weight contents (0.1, 0.3, and 0.5 wt%). The relationship between physical structure of aerogels (specific surface area and total pore volume) and mechanical properties of nanocomposites were evaluated. The fracture toughness of nanocomposites was investigated by both direct and indirect methods. The

In this work, we present crack propagation experiments evaluated by digital image correlation (DIC) for a carbon black filled ethylene propylene diene monomer rubber (EPDM) and numerical modeling with the help of variational phase-field fracture. Our main focus is the evolution of cracks in one-sided notched EPDM strips containing a circular hole. The crack propagation experiments are complemented

Based on least-squares support vector machine optimized using a quantum particle swarm optimization algorithm (QPSO-LSSVM), a prediction model was established to predict the fracture properties of polyvinyl alcohol fiber-reinforced cementitious composites (CCs) containing nano-SiO2 (PVA-CCNS) and improve its accuracy and effectiveness. Nineteen groups of measured data obtained from fracture performance

In this paper, a new approach for evaluating the Stress Intensity Factors (SIFs) using the interaction integral method with correction terms for cracks in three-dimensional Functionally Graded Material (FGM) is presented. The present interaction integral method allows us to adopt finite element models consisting of only tetrahedral finite elements with unstructured mesh arrangements. The proposed interaction

The mode-I fracture toughness of rock is one of the key mechanical indexes to measure the resistance of rock to its own crack propagation. The mode-I fracture toughness of rock mass in cold region is normally deteriorated by freeze–thaw cycle under temperature variation. Based on the theory of pore expansion, the meso-deterioration mechanism of pores in rock under the action of ice frost heave is analyzed

The influence of the 10% uniaxial and equi-biaxial tensile pre-strain on the notch fatigue performance of DP590 steel is investigated in the present study. Comparison has been made between smooth and notched specimens to recognize the effect of pre-strain on notch fatigue performance. The material’s fatigue strength improves from 240 MPa to 270 MPa, 294 MPa for the smooth specimen and from 91 MPa to

Fracture is an inherently statistical phenomenon as it is a function of micro-structural heterogeneities such as distributed defects and inclusions. This is evidenced by scatter in the toughness of seemingly identical specimens. Therefore, deterministic approaches do not give full picture of scatter in fracture behaviour. More suitable probabilistic methods have been devised to describe the scatter

The development of cracks inside concrete is harmful to the structural durability of seawater coral aggregate concrete (CAC) subjected to an aggressive marine environment. Thus, three-point bending (TPB) tests were performed on the notched beams to determine the fracture properties of cement-based CAC and slag-based alkali-activated CAC (AACAC) at different initial crack-depth ratios (a0/H = 0.2, 0

In this paper a simple analytical method is proposed to estimate an elastic-plastic strain and stress in the plastic zone ahead of the tip of a stable growing fatigue crack. Analytical estimations are compared with experimental results from digital image correlations (DIC) and integrated finite element (FE) analyses taken from literature. A fairly good agreement is demonstrated between the proposed

The study of dynamic fracture mechanism of pre-stressed coal is of great importance to the coal bursts prevention and the coal pillar reinforcement subjected to the dynamic disturbance. In this paper, the effect of pre-static load and dynamic load on the initiation fracture evolution and destruction states of coal were studied using experimental and theoretical approaches. The results show that the

Facture toughness measurement by cantilever bending has been widely used to study the fracture behaviour of different class of materials especially at the micro-scale. However, standard protocols of testing do not exist in these non-conventional geometries, leading to variable results. In this study we assess the geometric factors affecting the stress intensity factor solutions of a single edge notched

An ordinary state-based peridynamic (PD) shell model with arbitrary horizon domains is presented. In computations of the PD parameters, the model removes the complete horizon assumption when treating the PD surface effect. In this study, the membrane, bending, and transverse shear deformations in the PD framework are taken into account. To examine fracture mechanics behavior, crack opening displacements

Fissured rock mass is the most common construction object in geotechnical engineering and its mechanical properties are closely related to the stability of geotechnical engineering. A laboratory uniaxial compression test and a numerical simulation test were separately carried out on the fissured sandstone samples. Based on parameters, such as crack coalescence modes, the ratio of rise time to amplitude

The present article discusses the fracture behavior of medium-density fiberboard (MDF) and particleboard (PB), under mixed mode loading conditions. With wide applications in construction, marine and furniture industry, MDF and PB are two well-known, wood-based composites that are made of wood particles and fibers, adhered together using a standard polymer glue. Our examination of the elastic properties

A comparative study is carried out between two methods to estimate the strain intensity factor of a rigid line inclusion using the displacement and strain fields from digital image correlation (DIC). The two methods are (i) a proposed hybrid domain integral method and (ii) the linear over-deterministic least-squares technique involving multi-parameter displacement field equations (multi-parameter method)

Cracking simulation in concrete-like structures is the subject of numerous investigations of computational kind, in which different modeling techniques based on either smeared or discrete fracture approaches have been proposed. In this work, two different finite element-based cohesive fracture models, proposed by some of the authors and belonging to the discrete approaches, have been compared: (i)

In this research, the solution of linear elastic fracture mechanics problems when using spherical Hankel shape functions in the boundary element method is investigated. These shape functions benefit from the advantages of Bessel function fields of the first and second kind in addition to the polynomial ones, which makes them a robust and efficient tool for interpolation. Among the most important features

Subcritical crack propagation and rock creep deformation are the main factors affecting the long-term stability and strength characteristics of rocks under hydro-mechanical coupling. Triaxial creep tests were performed on rock-like mortar specimens containing a pre-existing 3-D crack to investigate the time-dependent mechanical behavior of the cracked rock. A modified theoretical model for the irreversible

This paper focuses on the effects of specimen type and thickness on the fracture parameters for I-II and I-III mixed mode cracks. Results show that mode III and mode II components emerge simultaneously near free surfaces of specimens under I-II and I-III mixed mode loadings, which is called coupling effect. For specimen under I-II mixed mode loading, the level of coupling effect is independent of specimen

When subjected to long-term static loading, with the accumulation of damage and fracture, brittle rock would fails when the static loading is lower than the compressive strength of the rock, and the increasing of the static loading can generally shorten the time required for the brittle rock failure. To explore the relationship between the durability of the brittle rock and the applied static loading

Reliability analysis of crack growth fatigue of titanium alloy is one of the important guarantees for the safety of deep-sea manned cabin. However, the traditional probabilistic fatigue reliability analysis methods often need accurate parameter statistics information. In this paper, under the condition of the limited test data, a first-order approximate ellipsoid non-probabilistic reliability analysis

The crack tip constraint effect should be considered in the fracture assessment of structures with cracks, and the in-plane constraint and out-of-plane constraint should be illustrated simultaneously for the three-dimensional cracks in practical engineering structures. The constraint effect of central cracked plate (CCP) specimens with I-II mixed mode crack under uniaxial compression has been investigated

Voronoi cell finite element models (VCFEM) containing pores and various cracks were developed in this study to simulate crack propagation in porous materials. In addition to polynomial terms, singular items were inserted into the stress function to capture the stress concentration at the tip of the crack. During crack propagation, the Voronoi element type changes such that an element may contain an

A novel isogeometric analysis enriched element for accurate evaluation of singularities arising at the interface in V-notched one-dimensional hexagonal piezoelectric quasicrystals (PQCs) under anti-plane loading is developed. By taking the advantages of IGA and symplectic methodology, an enriched element centered at the notch tip is constructed by analytical symplectic eigensolutions. Explicit expressions

Fracture toughness of anisotropic shale is an important parameter in shale-gas exploitation technology. Currently available literature is mainly focused on Mode I fracture toughness (KIC) of anisotropic rock under tensile loading. Although there are the cracked straight through Brazilian disk and crack ring disk used to determine Mode II fracture toughness (KIIC) of anisotropic rock under pure shear

Thin metal films in the nanometer range are extensively used for electronic and optoelectronic devices. However, the residual stress has a profound impact on the durability of the devices during their lifetime. This paper developed a two-dimensional (2D) elastic model to study the residual stress and opening-mode fractures (OMFs) in a film/substrate assembly. The fracture strength expressed by crack

A joint in the medium has a significant impact on the propagation of explosion stress wave and the growth of explosion-induced crack. In this work, the crack growth experiment in the PMMA(polymethyl methacrylate) medium with vertical open joints under explosion loading was first carried out on the digital laser dynamic caustics experimental system (DLDC), in order to analyze the crack initiation, growth

Crack paths in ferroelectrics under combined electromechanical loading have been investigated both experimentally and numerically in the past. The influence of electric fields on the deflection behavior being of particular interest, specimens exhibiting a pronounced curvature of crack growth have been predominantly considered. In this regard, a series of three-point bending tests with eccentric notch

The mismatch effect in weldment is widely to be found in engineering practices. In this paper, the material mismatch effect on the mode II creep crack tip field is investigated and discussed. The mismatch effect on the C(t)-integral is presented. Both the local mismatch and the general mismatch are found to play important role in C(t)-integral under mode II condition. The mismatch effect on the stress

We consider crack tip deformations under plane stress conditions of a Neo-Hookean sheet reinforced by Neo-Hookean fibers, whose orientation and elastic properties are described by discrete and continuous spatial distributions. The mechanical behavior of the composite is described in terms of the first and fourth invariant of the right Cauchy-Green tensor following Guo et al. [1], [2], [3]. The crack

It is difficult to accurately judge the crack propagation behavior at the interfaces of layered composite structures under impact loads. By mainly considering the influence of the loading rate on the interaction between a crack and an interface, this paper presents a new discrimination model to predict the crack propagation behavior. Based on the energy release rate criterion, which is used to judge

The fracture assessment of additively manufactured PLA and graphene reinforced PLA (PLA-GR) has been performed in this paper. Tensile and fracture specimens were fabricated with three different raster orientations (0/90, 30/−60 and 45/−45) in order to analyse the effect of the printing strategy on the resulting mechanical properties. A total of 30 tensile tests and 120 fracture tests were performed

To explore the deterioration response of rock engineering structure under seasonal acid rain, a large number of mixed mode I-III fracture experiments were conducted on sandstone with the edge notched disc bending (ENDB) specimens. Before fracture tests, all the sandstone samples were respectively subjected to 0, 2, 4, 7 and 10 wetting–drying cycles with hydrochloric acid solution to simulate the periodic

This paper proposes an effective FE modeling for simulating fracture propagation in linear elastic media under mechanical and thermal loadings. The model joins Moving Mesh (MM) technique with Interaction integral (M-integral) method to simulate crack advancing phenomena. MM reproduces growing cracks by moving the mesh nodes around the crack front, according to proper fracture criteria. In particular

Most studies of thermal effects on rock fracture have focused on Mode I, while the temperature-dependence and loading rate effect on Mode II fracture are rarely involved. We present the static and dynamic punch-through shear (PTS) tests, implemented on the INSTRON 1342 and the modified split Hopkinson pressure bar (SHPB) system respectively, as the approaches for determining the Mode II fracture toughness

This paper addresses a physical damage model and continuum damage-based fracture simulation procedure for simulating crack initiation, growth and cracks coalescence of quasi-brittle geomaterials. The model is proposed by using the principle of minimum dissipative energy combining with Drucker-Prager criterion, in which every parameter of the damage model has clear physical meaning. The procedure coupled

This paper aims to analyze the discontinuous crack closure behavior observed after a single tensile overload (OL) under otherwise constant ΔK loading. The investigation was performed on a disk-shaped compact tension DC(T) specimen made of Al6351-T6 with thickness of 2 mm, in order to simulate the case of a crack propagating under plane stress conditions. The Digital Image Correlation (DIC) technique

The presented paper deals with the mechanical properties of Friction Stir Welded (FSW) AA2024-T351-joints. The material’s response to the static and fatigue strength (S–N curve) is summarised from previous work and referenced, while the testing methods and results for the fatigue and fracture mechanics’ parameters regarding to the fatigue crack growth and occurrence of final fracture are discussed