Towards measuring the mixed-mode I + III fracture toughness independent of geometry and loading type, two test specimens were numerically and experimentally compared. The capabilities of edge-notched disc bend (ENDB) and edge-notched diametrically compressed disc (ENDC) fracture test specimens were compared in producing the full range of mixed-mode I + III. Although the geometry of both specimens was

The present work addresses the micromechanical modeling and the simulation of crack initiation and propagation in ductile materials failing by void nucleation, growth and coalescence. A cohesive-volumetric approach is used and the overall material behavior is characterized both by a hardening bulk constitutive law and a softening surface traction-separation law embedded between each mesh of a finite

Our chief target of this paper is to study the temperature-dependent Nishihara-type model(TDNM) with creep damage based on the Caputo fractional derivative. The Vogel–Fulcher–Tammann (VFT) law is considered due to its property between the viscoelastic and the temperature. Consequently, the improved Nishihara-type model coupled with the thermal effect is reassembled by the Caputo-Mainardi dashpot and

The VCHF fatigue characteristics of orthogonal plain weave composite material under UV radiation had been carried out by an ultrasonic resonance device. A compound cooling method was used to ensure the fatigue test working under continuous loading conditions. S-N curves under different reliability levels, and fatigue life survival probability distribution were plotted. UV radiation reduced the mechanical

In the present work, a phase field numerical manifold method (PFNMM) is proposed for crack growth in brittle materials. The advantages of the phase field method (PFM) in modeling crack initiation and crack branching, and those of the numerical manifold method (NMM) in discretizing the computational model are integrated together in the proposed numerical model. The proposed numerical model is very suitable

This investigation focuses on the dependence of stable crack growth resistance, as measured by the short-rod fracture toughness test, on secondary void-initiating particles such as AlN and Ti-based grain-refining precipitates in a variety of high-strength steels with tempered martensitic microstructures. The model developed by Ritchie and Thompson is modified to illustrate the significant amounts of

In this work, a novel methodology for fracture characterization of metallic notched components including the effect of notch root radius and temperature is proposed based on the brittle-to-ductile transition curve. To this aim, two different regression models are derived, either by considering temperature as an influencing variable or combined with the notch radius effect. In the former case, the compatibility

The determination of fracture behaviour of welds in presence of internal hydrogen is essential for the integrity assessment of CrMo vessels and pipes working under high hydrogen pressures. Homogeneous coarse-grain tempered bainitic/martensitic microstructures were obtained in 42CrMo4 and 2.25Cr1Mo steels by means of laboratory heat treatments in order to reproduce the coarse grain heat affected zone

To compare the rock breaking mechanism of the tunnel boring machine (TBM) hob under traditional condition and free-face condition, a series of rock cutting tests and rock cutting simulations of the TBM hob under two cutting conditions are conducted. The rock chip, rock breaking forces and rock breaking efficiency etc. are investigated in this study. The research results denote that the rock chip size

This work focuses on the technological size effect of the cast aluminium alloy EN-AC 46200. Herewith, specimens inheriting specific local cooling rates and therefore varying local dendrite arm spacings are taken from crankcases with hot isostatic pressing (HIP) post-treatment. In order to evaluate the statistically distributed microstructural properties, the dendrite arm spacing λ2 is probabilistically

A finite element model of a tapered tensile specimen with a hardness transition zone in the gauge section and a varying width parameter is used for creating corresponding solution snapshots. Subsequently, a long short-term memory (LSTM) recurrent neural network (RNN) is trained on the selected snapshots, providing a parametrized solution model for a computationally efficient prediction of the structural

Peeling and cleavage are common load cases for studying and evaluating adhesion between materials. The former is suitable for testing adhesion of thin or highly flexible materials for which the bending energy is negligible while the latter uses the rate of released bending energy as a measure of fracture energy. Their data reduction schemes are very different, which could lead to situations where peel-cleavage

The applicability of Irwin’s estimate to metals containing particles becomes dubious when the plastic zone (PZ) size is comparable to the particle spacing. Therefore, a multiscale model is used to investigate the crack tip plasticity in a cyclically loaded elastic-perfectly plastic matrix containing a realistic distribution of spherical particles. Homogenization and dimensional analysis demonstrate

For a better understanding of acoustic emission (AE) characteristics and failure mechanism of specimens containing hole-like flaw, a series of uniaxial compression tests are carried out by using the bonded-particle model (BPM). In the BPM, the AE simulation combined with moment tensor inversion is adopted. The results indicate that the stress drop in the stress-strain curve corresponds to a sudden

The general consensus in the literature is that the fracturing behavior of nuclear graphite shows a certain degree of nonlinearity due to the presence of a fracture process zone (FPZ) ahead of the crack tip. Thus, it is necessary to take the influence of the FPZ into account when investigating the fracture properties of nuclear graphite. Besides, the energy-based approach has been widely used to characterize

The most important ability of fracture mechanics is how to apply the material test data obtained by standard specimens with the through-thickness cracks to practical structures where partially penetrating crack growth usually spends most of the service life, but complicated stress states make it difficult to describe the creep crack border stress states effectively. Based on the creep stress intensity

To study rock breakage between indentations for various indenters, a constant cross section (CCS) indenter and 4 built-up indenters (named W1, M1, M2 and M3) containing various cutting teeth were prefabricated. Then, 25 indentation tests were performed on sandstone specimens using these indenters. The indentation tests show that internal cracks connected the adjacent plastic zones when the indentation

Laser cladding is an additive manufacturing process which is spreading as a valuable resource for manufacturing and repairing mechanical components that are subjected to intense wear. Advantages over conventional welding include a much lower heat input and minimal dilution, also surpassing metal spraying due to the resulting metallurgical bond. In this paper, the effect of laser cladding on the fatigue

Since its proposal, the simplified Spb method has been successfully applied to the fracture toughness evaluation of metallic and polymer materials. However, some points of this methodology remain unclear, like the applicability on standardized geometries in which ηpl depends on the a/W ratio. In order to discuss this and other aspects, theoretical analyses of the Spb method were made and some experimental

Studies show that sharp and blunt notches can be classified in the same research system. In the present study, the virtual-real caustics experimental method is applied to investigate the influence of the notch curvature on the impact fracture behavior of the three-point bending beam with a notch. Moreover, the loading characteristics of the drop hammer impact and the dynamic process of specimen fracture

This work aims to introduce an alternative technique to address the fracture process of brittle and quasi-brittle materials under the Material Point Method (MPM) framework. With this purpose the eigensoftening algorithm, developed originally for the Optimal Transportation Meshfree (OTM) approximation scheme, is extended to the MPM to present a suitable alternative to the existing fracture algorithms

The paper describes a numerical approach to represent cracking along non-pre-established directions, in 2-D structures or domains of quasi-brittle materials such as concrete or rock. The approach is developed on the basis of the FEM with zero-thickness interface elements, combined with the principles of Configurational Mechanics. Interface elements are pre-inserted along all potential crack lines in

Being a combination of sand, cement, water, and asphalt emulsion, Cement Emulsified Asphalt Mortar (CEAM) has better toughness and flexibility properties than cement mortar. Given the multiphase nature of CEAM, it is susceptible to micro-cracking during the setting process and also due to other factors such as traffic loads, undesirable atmospheric conditions. Given the typical direction of loading

This research work reports the impact of adding synthesized Tricalcium Phosphate (β-TCP) and commercial Titania powder (TiO2) on the mechanical and tribological properties of Alumina (Al2O3). In fact, the commercial Al2O3 mingled with β-TCP and commercial (TiO2) to obtain a mixture which considered as a bioactive coating that may be used in orthopedic implants. Representative bioceramic samples of

Rock masses consist of various discontinuities that significantly affect the crack development patterns which dominates the ultimate failure of geostructures. The interaction of the pre-existing flaws with each other and with the newly formed cracks is complicated and demands a comprehensive investigation. This paper couples the 3D printing technology with the digital image correlation (DIC) and the

A methodology for simulating plasticity induced crack closure and crack shape evolution based on elastic–plastic fracture parameters is proposed, which represents a new way to predict fatigue crack growth in small and large scale yielding scenarios. The methodology consists in solving iteratively a single elastic–plastic finite element model, for which the load history is kept by remeshing and mapping

The present study is focused on the characterization of the fatigue damage features in carbon/epoxy laminates under mode-II loading conditions. To this aim, a sinusoidal cyclic load was applied to the End-Notched Flexural (ENF) specimens and the fatigue behavior of specimens was investigated. Scanning Electron Microscope (SEM) was used to identify the damage features on the fracture surface, i.e. fiber

Rocks in civil and mining engineering usually experience rather complex stress disturbance. Rock dynamic mechanical behaviors under constant stress amplitude condition have been widely studied. However, the rock fracture evolution characteristics subjected to multi-level cyclic loading conditions are not well understood. In this work, multi-level cyclic compressive loading experiments were performed

Electrically conductive adhesives (ECAs) are starting to replace metallic solders in recent designs of photovoltaic (PV) modules. This transition represents a significant material change, and a proper understanding of the durability and reliability of the new interconnect needs to be established. This paper presents our continued work on developing a degradation model for ECA interconnects in PV modules

The present work aims to present a new complete procedure to characterize fracture toughness in terms of stress intensity factor K or the J−Integral for Mode I of loading using four-point bending specimens. Four-Point Bending (4PB) specimens are shown to be valid configurations for fracture toughness characterization tests with certain advantages when compared to traditional three-point bending geometries

This technical note demonstrates the use of tetrahedral meshing for modelling a slanted semi-elliptical surface crack at a solid cylinder by finite element method (FEM). For a relatively small ratio of the crack depth over cylinder diameter, Modes I and II (in-plane) stress intensity factors (SIFs) at the corner points by FEM were observed to be in good agreements with those by the dual boundary element

Rock masses contain various discontinuities such as flaws, cracks, join sets and more, each significantly affect the crack initiation, propagation and coalescence patterns of new cracks which dominates the ultimate failure of geostructures. The interaction of the pre-existing flaws with each other and with the newly formed cracks is complicated which demands a comprehensive look into the phenomenon

A great research effort has been spent during the latest years in the characterization of additive manufacturing (AM) alloys, mostly focused on the analysis of microstructure and on the assessment of mechanical strength, especially under high cycle fatigue loads. Post-process treatments have been also investigated, as methods to further improve the AM materials performance. On the contrary, still fewer

The failure and mechanical behavior of transversely isotropic rock are significantly affected by the original bedding planes. Until now, few studies have been performed to investigate the influence of the geometrical and mechanical parameters of the bedding planes on the fracture characteristics of transversely isotropic rocks under planar shear fracture loading conditions. For this purpose, experimental

A continuous-discontinuous cellular automaton method (CDCA) is developed for dynamic crack propagation. First, a separated time integral scheme is built, in which time difference is divided into two separated time steps: one balances the change of the geometric discretization caused by crack growing, and the other balances the dynamic loading. Second, an adaptive energy conservation strategy is proposed

The load-carrying cruciform welded joint usually fails in the weld root or the weld toe. Determining the failure location in terms of the stress intensity factor (SIF) of the crack at the weld root and the weld toe is an alternative. Various SIF equations have been proposed and incorporated in the British Standard (BS) 7910:2013, including the equations for the welded cruciform joint with a weld toe

In this study, the fracture toughness at the bi-material interface of layered test pieces is determined using digital image correlation (DIC) measurements as part of dynamic shear tests. High-strain-rate shear tests are conducted on a three-layered bonded test piece comprising a central aluminum layer with PMMA resin layers. When the crack is sufficiently shorter than the bonding interface length,

The grain-based model (GBM) in two-dimensional Particle Flow Code (PFC2D) is widely employed to investigate the mechanical response characteristics of crystalline rocks under external load considering the realistic petrographic texture. However, due to the poor self-locking effect of the Parallel-Bond (PB) inside the minerals and unreasonable parametric assignment for the Smooth-Joint (SJ) at the mineral

To introduce more fibre-reinforced polymers in cars, the automotive industry is strongly dependent on efficient modelling tools to predict the correct energy absorption in crash simulations. In this context, an adaptive modelling technique shows great potential. However, as the critical energy absorption in a crash occurs over a very short period of time, and since the deformation behaviour is very

The scaled boundary finite element method is developed for transient thermoelastic fracture analysis. To enable this, a set of novel shape functions are derived considering thermoelastic equilibrium. The salient features of the proposed framework are: (a) can be formulated on polygons with an arbitrary number of sides leading to flexible mesh generation and (b) facilitates an accurate and direct evaluation

In this contribution, a nonlocal approach is proposed to model the dynamic damage of quasi-brittle composites within the framework of the scaled boundary finite element method (SBFEM). The image-based quadtree decomposition is used to automatically achieve multi-level mesh of a domain with geometric as well as material discontinuities. By enforcing a 2:1 balanced condition, only limited types of S-domains

The development of a fracture process zone (FPZ) (microcrack zone) ahead of a fracture tip is a prominent fracture characteristic of rock-like materials. At present, understanding of the quasi-static loading-rate effect on the FPZ development of a mixed-mode (I-II) fracture remains challenging for rock-like materials. In this paper, the centrally cracked Brazilian disk (CCBD) specimens of artificial

Tension and fracture toughness JIc tests were performed on both as-welded and heat-treated conditions. The softer tempered martensitic matrix and the transformation-induced plasticity (TRIP) of reformed austenite improved significantly the strain hardening behavior of the heat-treated material. These matrix characteristics were found to retard micro-void nucleation during straining. The onset of necking

This paper is concerned with the problem of a Yoffe-type moving crack along the interface of an infinitely long piezoelectric bi-layer with the distinct strip-like electrical saturation and mechanical yielding zones in front of the crack tips. In this paper, we simplify the mixed boundary value problem into coupling Fredholm integral equations of the second kind by applying the Fourier integral transformation

Foreign object damage (FOD) tests and high-cycle fatigue (HCF) tests were carried out for Ti-17 titanium alloy simulation blades. The results showed that damage notches could be divided into semicircular and deflection types. The HCF strength of deflection-type specimens was lower than that of semicircular-type specimens. FOD and fatigue properties were characterized by scanning electron microscopy

The mechanical behavior of earth concrete for sustainable construction has been studied in this paper. The effect of flax fibers on the fracture behavior has been monitored using digital image correlation (DIC) and acoustic emission (AE) techniques to better understand the fracture process and damage mechanism. Three-point bending tests have been conducted on prismatic specimens with different percentages

Fatigue design assessment is a crucial step in the design process of ships and offshore structures. To date, the stochastic approach is commonly used to calculate the total lifetime accumulated fatigue damage and the probability of fatigue failure for the structures. Meanwhile, the details of damage initiation and propagation are infrequently investigated. In terms of predicting crack growth, the traditional

In order to investigate the development characteristics and size effect of rock fracture process zone (FPZ), the GCTS RTX-3000 rock mechanics testing machine was used to carry out on semi-circular bend (SCB) sandstone specimens with diameters of 50 mm, 100 mm, 150 mm and 200 mm, respectively. Combined with the digital image correlation (DIC) method, the variations of the displacement field at the crack

We propose a new direction-dependent model for the unilateral constraint involved in the phase field approach to fracture and also in the continuous damage mechanics models. The construction of this phase field model is informed by micromechanical modeling through the homogenization theory, where the representative volume element (RVE) has a planar crack in the center. The proposed model is made closely

Since welded joints in structures are known to be critical regions for crack initiation and growth, study of fatigue crack growth behavior of welded joints under various loading scenarios are essential. In present study, two groups of experiments were conducted. At first, fatigue crack growth behavior of Al5083 butt welded joint subjected to mixed mode loading with constant amplitude has been studied

In this work, an extended finite element method with partial Heaviside function enrichment (XFEM-P) in the crack tip element is proposed for fracture analysis for the first time. In this method, the crack tip element is divided into cracked and uncracked domains naturally by the crack geometry. In the cracked domain, Heaviside function enrichment is employed to simulate the crack discontinuity across

This paper highlights a method for determining crack initiation force in adhesives used for single-lap joints (SLJs). Crack onset behavior was investigated by combining multiple techniques of failure progressive analysis. The proposed relative displacement method (RD) incorporated digital image correlation (DIC), focusing on bending strain behavior responses to the RD of substrates. Deformation acceleration

The zero-degree peeling behavior of the highly stretchable adhesive tape on a rigid substrate was investigated. To explicitly consider the influences from the viscoelasticity, hyperelasticity and visco-hyperelasticity of the tape on the peeling performance, the analytical formulae were proposed based on a simple and effective energy approach. Assuming the interface adhesion energy to be constant, the