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In this study, finite element modeling and experimental studies on a mode-I/III specimen similar to the compact tension specimen are presented. By using bolts, the specimen is attached to two loading apparatus that allow different levels…
The paper deals with the Stress Intensity Factor assessment of cracks at the intersection of holes loaded by internal pressure. Triangular flaws are considered at the intersection of two holes inside a specific specimen. The research…
The CJP model of crack tip stresses is a modified version of the Williams crack tip stress field which takes account of simplified stress distributions that arise from the presence of a zone of plastic deformation associated with the crack…
This paper describes a novel method to model the stress gradient effect in fretting-fatigue. The analysis of the mechanical fields in the proximity of the contact edges allows to extract nonlocal intensity factors that take into account…
The weight function method provides a powerful and reliable tool for the determination of the stress intensity factor around the crack tip in a linearly elastic cracked solid subjected to arbitrary loading conditions. However, it is…
In stress analysis of cracked plates, alongside the stress intensity factor which quantifies the singular stress component perpendicular to the crack plane, the role played in crack growth by the constant term parallel to the crack plane…
In this work, a link between the averaged strain energy density (SED) approach and the peak stress method in the case of cracks subjected to mixed mode (I+II) loading has been investigated. Some closed-form expressions of the strain energy…
In this work, a link between the averaged strain energy density (SED) approach and the peak stress method in the case of cracks subjected to mixed mode (I+II) loading has been investigated. Some closed-form expressions of the strain energy…
This study based on a new fracture mechanics parameter is concerned with assessing the integrity of cracked steam turbine disk which operate under startup-shutdown cyclic loading conditions. Damage accumulation and growth in service have…
This paper focusses on discussing equivalent stress intensity factors and kink angles after a change of mode-mixity from one cycle to the next and when the mode-mixity changes continuously during the fatigue cycles. Thin-walled tubes with…
The linear elastic analysis of cracked bodies is a Twentieth Century development, with the first papers appearing in 1907, but it was not until the introduction of the stress intensity factor concept in 1957 that widespread application to…
Nowadays, fibre-reinforced composite materials are widely used in many fields, e.g. automotive and aerospace. Natural fibres such as flax and hemp provide good density specific mechanical properties. Additionally, the embodied production…
The crack growth behavior of the aluminum alloy 6061 T651 was investigated using cruciform specimens with a measurement area of 120 x 120 x 2 mm3 with two center crack configurations of the starting notch parallel to one of the loading…
According to the classical definition for in-plane modes of crack deformation, the constant stress term T exists only in the presence of mode I. However, recent studies show that this term can exist in mode II conditions as well, and…
The linear elastic analysis of homogeneous, isotropic cracked bodies is a Twentieth Century development. It was recognised that the crack tip stress field is a singularity, but it was not until the introduction of the essentially two…
The purpose of this article is to present the stress intensity factors (SIF) solutions for semi-elliptic crack in pipelines under internal pressures, the stress intensity factors are calculated by the three-dimensional finite element…
In this paper the effect of reinforcement crack position and loading conditions (in mode I) on the stress intensity factors of the Al/SiCp metal matrix composite was examined using a finite element method. A simple cubic cell model with…
In this study, multiple and non-planar crack propagation analyses are performed using Fracture and Crack Propagation Analysis System (FCPAS). In an effort to apply and validate FCPAS procedures for multiple and non-planar crack propagation…
This is the first part of a short three-paper series, aiming to revisit some classical concepts of Linear Elastic Fracture Mechanics. The motive of this first paper is to highlight some controversial issues, related to the unnatural…
This study develops stress intensity factor (SIF) solutions for cladded WWER reactor pressure vessel nozzles subjected to pressurised thermal shock loading. Although finite element analysis is widely used for fracture assessment…
A finite rectangular plate of unit thickness with two inclined cracks (parallel and non parallel) under biaxial mixed mode condition are modelled using finite element method. The finite element method is used for determination of stress…
In this study a procedure to stress intensity factors calculation for imitation models made of titanium alloy is described. In service fatigue cracks are detected in a disk and blade “dovetail type” attachment. On the base of this…
In the last two decades, visual image techniques such as Digital Image Correlation (DIC) enabled to experimentally determine the crack tip displacement and strain fields at small scales. The displacements are tracked during loading, and…
Fully automatic fatigue crack growth simulation system is developed using S-version FEM (SFEM). This system is extended to fracture in heterogeneous material. In the heterogeneous material, crack tip stress field becomes mixed mode…
In this study, to investigate and understand the nature of fracture behavior properly under in-plane mixed mode (Mode-I/II) loading, three-dimensional fracture analyses and experiments of compact tension shear (CTS) specimen are performed…
This paper is devoted to the analysis of the load path effect on I+II+III mixed mode fatigue crack propagation in a 316L stainless steel. Experiments were conducted in mode I+II and in mode I+II+III. The same maximum, minimum and mean…
Axles and shafts are of prime importance concerning safety in the transportation industry and railway in particular. Design rules for axles and shafts are mainly based on endurance curves for the material used according to the established…
A three-dimensional crack propagation simulation is performed by the Dual Boundary Element Method (DBEM). The Stress Intensity Factors (SIFs) along the front of a semi elliptical crack, initiated from the external surface of a hollow axle…
In this work it is proposed a methodology for the evaluation of plasticity-induced crack shielding from the analysis of the crack tip displacements fields measured by digital image correlation. This methodology is based on the evaluation…
This paper deals with the influence of the cold drawing process on the fracture behaviour of pearlitic steels. To this end, fracture tests under axial loading were performed on steel wires with different drawing degree (from a hot rolled…
In this study, the three-dimensional finite element method is used to analyze an API 5L X70 steel cylindrical pipeline subjected to an internal pressure load by calculating the stress intensity factors and the integral J at the peak of…
In this paper the fatigue crack growth tests were carried out on surface-crack tension (SCT) specimens, made of 7050 and Ti6Al4V alloys, with initial semi-elliptical surface cracks. Pure Mode I conditions were realized on SCT specimens…
The stress-strain state analysis of the gas turbine engine compressor disk was carried out taking into account damage accumulation under various loading conditions in the temperature range. Characterization of the constraint effects was…
This paper analyses industrial PVC sheets structural integrity assessment widely used for different ranges of industrial applications. We investigated combined approaches focused on fracture toughness assessment to predict PVC mechanical…
The initiation and propagation of fatigue cracks during cyclic torsion loading was studied in a cast Al alloy (A357) with a relatively large (~500 ?m) grain size. 2D observations, revealed that multi site crack initiation occur on the…
An experimental campaign was carried out on thin-walled tubes under tension and torsion. The results from experiments are measured and compared. It is observed that cracks follow a shear-dominated growth pattern with increasing crack…
In this paper, a general weight function was developed to calculate the stress intensity factors (SIFs) for quarter-elliptical cracks in a wide range of lug attachment family. For this purpose, a series of finite element analyses were…
From experimental and theoretical investigations it is known that cracks are sensitive to geometry, e.g., to the inclination angle to the load. A small deviation of a crack from the normal direction to a tensile load causes mixed mode…
Ductile cast irons (DCIs) are characterized by a wide range of mechanical properties, mainly depending on microstructural factors, as matrix microstructure (characterized by phases volume fraction, grains size and grain distribution)…
For various configurations examined in a series of fatigue experiments on thin-walled tubes under tension and torsion, the experimental results – crack path, crack growth life, near crack tip deformations, and crack closure – are measured…
An important topic of the Collaborative Research Centre TRR 30 of the Deutsche Forschungsgemeinschaft (DFG) is the crack growth behaviour in graded materials. In addition, the growth of cracks in the neighbourhood of regions and through…
Digital image correlation (DIC) is a technique in experimental mechanics to acquire full-field measurement data of displacements and deformations from the surface of specimens or components. Especially for the investigations of cracks it…
In this paper, determination of the accurate notch stress intensity factors (NSIFs) have been demonstrated using a recently proposed technique: The point substitution displacement technique (PSDT) for the sharp Vnotched configurations. In…
The present work summarizes a numerical procedure aimed at the evaluation of the residual strength of a cracked lap joint, based on the competing failure mechanisms regulated by the R-curve analysis and plastic collapse. The model adopted…
In mixed-mode conditions, the competing contribution of the different stress intensity factors predicts fracture initiation load as well as crack propagation direction. Commonly, mixed-mode fracture resistance is based on the assumption of…
Closure-free long cracks under the remote mode III loading grow in a more complicated way than those under the remote mode II. For bcc metals, a coplanar in-plane spreading of tongues driven by the local mode II loading components at…
In this study, experimental and numerical results of compact tension shear (CTS) specimen and a new specimen type under in-plane mixed mode (Mode-I/II) loading conditions are compared with existing inplane mixed mode fracture criteria to…
The fivefold symmetric modular stellarator Wendelstein 7-X (W7-X) is currently under construction in Greifswald, Germany. The superconducting coils of the magnet system are bolted onto a central support ring and interconnected with five…
The publication presents a cruciform specimen for the determination of cyclic crack growth data under biaxial loading. The design of the specimen with slotted loading arms allows good decoupling between the two loading directions. For…
This study represents a methodology to assess the probability of failure based on three the driving force formulations defined by the corresponding brittle and ductile fracture criteria for compact and bending specimens made of 34XH3MA and…
