October 2014
The browsable journal is available at this link
Dear Friend,
this issue is one of the most rich we ever published!! Dozens of high quality papers mainly, but not uniquely, connected to the Multilateral workshop organized in cooperation with our portuguese and spanish friends. Grupo Español de Fractura, Gruppo Italiano Frattura and Sociedade Portuguesa de Materiais (SPM)/Fracture Division organized The First Multi-Lateral Workshop on Fracture and Structural Integrity related Issues in Catania, in the same venue that will be used in 2016 for the 21st European Conference on Fracture (ECF21)… a test is always better!
The organizers of The First Multi-Lateral Workshop on Fracture and Structural Integrity related Issues were:
- Paulo De Castro (Universidade do Porto, Portugal);
- Manuel de Freitas (EDAM MIT, Portugal);
- Francesco Iacoviello (Università di Cassino e del Lazio Meridionale, Italy);
- Antonio Martín-Meizoso (Universidad de Navarra, Spain);
- Luca Susmel (University of Sheffield, UK);
- Jesús Toribio (Universidad de Salamanca, Spain)
More than 70 presentations are an undoubted success … and the success of this event was also due to the efforts of all the members of the IGF ExCo… without their help, the organization of this event, and also of all the IGF events, would be simply impossible.
Beppe and Donato (the Vice Presidents), Angelo (the Treasurer) and Andrea, Carmine, Giacomo, Vittorio …
THANK YOU!!
Warmly acknowledgments are also due to GOM Tecnologie di Misurazione Ottica, MTS and Leica Microsystems. Their support allows to IGF to organize its events and we are grateful for their constant help. In addition, we wish to thank ESIS (European Structural Integrity Society), ICF (International Congress on Fracture) and AIM (Associazione Italiana di Metallurgia) for their sponsoring.
Finally, a few words about the cover. After some years, we decided to change the cover of the IGF journal, simplifying the content and modifying the main picture. As you can see, this picture is a “scheme” of the Eiffel Tower with some evident modifications, in order to underline the main topics of our journal. Hoping that the new cover will be appreciated, we wish to propose to all of you to send us your ideas for new covers. The best ones will be used for the next issues, obviously with warm acknowledgements to the authors!!
Francesco Iacoviello
F&IS Chief Editor
In Nature there are many examples of materials performing structural functions. Nature requires materials which are stiff and strong to provide support against various forces, including self-weight, the dynamic forces involved in movement…
The dynamic fragmentation of rock within rock avalanches is examined using the fragmentation concepts introduced by Grady and co-workers. The analyses use typical material values for weak chalk and limestone in order to determine…
Cutting processes affect the material to a deeper or shallower attached-to-the-cut zone. Its microstructure, its hardness and mechanical properties are changed. Also the cutting process introduces surface roughness and residual stresses.…
Engineering components often contain notches, keyways or other stress concentration features. These features raise the stress state in the vicinity of their apex which can lead to unexpected failure of the component. The Theory of Critical…
Chemical reactions between carbon steel, water and chemical species produce corrosion layers (scales) on the internal surface of pipelines transporting hydrocarbons. Scales act as a diffusion barrier and prevent the progress of corrosion…
Offshore wind parks at locations further from the shore often involve serious difficulties, e.g. the maintenance. The bearings of offshore wind turbines are prone to suffer hydrogen-assisted rolling-contact fatigue (HA-RCF). Three…
The Bartolomeo Colleoni monument suffered for years damage from the local climate. The process of restoring the Colleoni equestrian statue, started in 2003, allowed to understand how the bronze statue was originally cast and manufactured…
The aim of the paper is to estimate a value of the critical applied stress for a crack initiation from a sharp V-notch tip. The classical approach of the linear elastic fracture mechanics (LELM) was generalized, because the stress…
The analysis of the damaging micromechanisms in Ductile Cast Irons is often focused on ferritic matrix. Up to ten years ago, for this grades of DCIs, the main damaging micromechanism was identified with the graphite elements – ferritic…
Chemical Vapour Infiltration (CVI) technique has been long used to produce carbon/carbon composites. The Pyrolytic Carbon (Py-C) matrix infiltrated by CVI could have different microstructures, i.e. Rough Laminar (RL), Smooth Laminar (SL)…
There is growing interest in the use of self-consolidating cementitious systems in construction industry. The present research was conducted to enhance the mechanical performance of cement composites by the utilization of micro-sized inert…
In the present article, a review of the complete characterization in different aggressive media of a Ti-6Al-4V titanium alloy, performed by the Structural Mechanics Laboratory of the University of Bergamo, is presented. The light alloy has…
There has been a trend recently to use specimen geometries for toughness measurement that are more representative of actual flaw geometries in service. A prominent example is the use of single-edge-notched tension specimens for assessment…
This paper investigates the fracture properties and notch effect of PUR materials with four different densities. The asymmetric semi-circular bend specimen was adapted to perform mixed mode fracture toughness tests. This semi-circular…
This paper analyses the influence that the type of geometry used to obtain the stress/strain fields in a cylindrical contact has on fretting fatigue life predictions. In addition, this work considers the effect that the fatigue crack shape…
In order to correctly assess the biaxial fatigue material properties one must experimentally test different load conditions and stress levels. With the rise of new in-plane biaxial fatigue testing machines, using smaller and more efficient…
The present work has investigated the fracture toughness of a model DGEBA epoxy system subject to Hidro-Thermal aging. A Photoelastic Stress Analysis technique has been implemented, showing the evolution of stresses arising throughout the…
The soil mechanic laboratory results help in accurate soil foundation design and enhancement failure mitigation. The mixing soil design has been used in many geotechnical engineering for soil improvement. In this paper, several types of…
Marble slabs, typically used as façade panels to externally cover buildings, might permanently deform after a certain time of environmental exposure. This phenomenon, called bowing, is generally accompanied by a reduction of strength which…
Very often computations on structural elements or machine components subjected to variable loading require using an advanced finite element model. This paper reports the numerical implementation of a model for multiaxial cyclic…
A set of heterogeneous and homogeneous materials differing in their brittle and ductile characteristics (granite, marble, silica ceramics, silicon carbide, organic glass) were subjected to impact damaging by a falling weight. Multiple…
Crack tip stress-induced phase transformation mechanisms in nickel-titanium alloys (NiTi) were analyzed by Digital Image Correlation (DIC), under fatigue loads. In particular, Single Edge Crack (SEC) specimens, obtained from a commercial…
In the present paper, the well-known wedge splitting test (WST) is applied on specimens with different geometries (S= 150, 200, 300 mm) and variants of the specimens’ configurations. K-calibration (B1) and T-stress (B2) calibration curves…
The aim of this paper is to calculate how the surface crack front and the dimensionless compliance evolve in cracked cylindrical bars subjected to cyclic tension or bending with different initial crack geometries (crack depths and aspect…
The energy dissipated to the surroundings as heat in a unit volume of material per cycle, Q, was recently proposed by the authors as fatigue damage index and it was successfully applied to correlate fatigue data obtained by carrying out…
Static traction tests on material samples for mechanical constructions have pointed out the loss of linearity of the specimen surface temperature with the applied load. This phenomenon is due to the heat generation caused by the local…
Residual stresses occur in many manufactured structures and components. Great number of investigations have been carried out to study this phenomenon. Over the years, different techniques have been developed to measure residual stresses…
In this paper the so-called Theory of Critical Distances is reformulated to make it suitable for estimating the strength of notched metals subjected to dynamic loading. The TCD takes as its starting point the assumption that engineering…
Aim of the present work was the instrumentation of a maxi scooter for the field collection of service loads acting on the scooter main components such as frame, fork, handlebar, rear frame and suspension. Service loads were collected on an…
Peeling is a physical mechanics involved in the detachment of many natural and industrial applications. In this paper, we investigate the double peeling of an endless elastic pre-stressed tape adhering to a flat smooth rigid substrate.…
In this paper a methodology for evaluating crack initiation under biaxial conditions is presented. The methodology consists of evaluating the crack length automatically with digital processing of highmagnification images of the crack. The…
In this work, the use of circumferentially cracked bar (CCB) sample to determine material fracture toughness in the upper shelf regime for carbon steels has been investigated. Since high fracture toughness materials are known to exhibit…
Cracks in cover of reinforced and pre-stressed concrete structures significantly influence the ingress of deleterious species causing decrease in durability of these structures. The paper is focused on the effect of fracture process on two…
AISI 304L stainless steel specimens have been tested in fatigue. The tests were axial, torsional and in-phase biaxial, all of them under load control and R=-1. The S-N curves were built following the ASTM E739 standard and the method of…
Components and structures are designed based in their material’s mechanical properties such as Young's modulus or yield stress among others. Often those properties are obtained under monotonic mechanical tests but rarely under cyclic ones.…
Learning from history is, by popular account, something at which human beings are not particularly good; George Bernard Shaw having stated that “we learn from history that we learn nothing from history”, while the Spanish philosopher…
The aim of this scientific work was to investigate the behaviour of cruciform welded joints under static loading using a full-field technique: Digital Image Correlation. The material curves, relative to different zones (base material, heat…
The plastic zone is theoretically and numerically analyzed for various combinations of the nonsingular terms xx T to zz T ratios in connection with specimen thickness under mode I loading. The plastic zone size distribution is based on the…
In this work the mechanical behaviour of a core reinforced composite sandwich structure is studied. The sandwich employs a Glass Reinforced Polymer (GRP) orthotropic material for both the two external skins and the inner core web. In…
The Miner number M, used as a tool for lifetime prediction of mechanical and structural components in most of the standards related to fatigue design, is generally accepted as representing a damage stage resulting from a linear progression…
The paper delivers a critical review of the research data on the crack initiation and crack growth patterns characteristic of the components of the spline-bolted joints between the propeller shaft and reducer shaft at An-24, An-26, and…
In this work, the mechanical properties of Waspaloy superalloy have been evaluated in case of welded repaired material and compared to base material. Test program considered flat specimens on base and TIG welded material subjected to…
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…
This paper presents a simple experimental procedure that greatly facilitates the use of digital image correlation (DIC) techniques in fatigue test conducted in resonant testing machines, without the need of test interruptions. This is…
This paper describes the use of models of fracture-plastic materials for reinforced concrete in numerical modelling of beams made from reinforced concrete. The purpose of the paper is to use of a model of concrete for modelling of a…
The modified compact tension (MCT) test, though not yet recognized as a valid test for determining fracture energy of concrete, is believed to represent a plausible and suitable alternative versus other well established procedures, such as…
Experimental indentations are carried out on items of two different materials, taken in several location of various components from high pressure gas turbine rotor which have seen an extensive service. The components object of…
The benefits of resins nano-enhanced on the impact response of sandwich composites made by fiber glass/epoxy skins and balsa wood core were studied. Afterwards, the influence of the core's discontinuity was analyzed in terms of impact…
During a ferry flight, in a standard operation condition and at cruising level, a military cargo experienced a double hydraulic system failure due to a structural damage of the dual booster actuator. The booster actuator is the main…
In recent years, very-high-cycle fatigue (VHCF) behavior of metallic materials has become a major point of interest for researchers and industries. The needs of specific industrial fields (aerospace, mechanical and energy industry) for…
This paper analyses how the microstructure of an eutectoid pearlitic steel affects its conventional mechanical properties (obtained by means of a standard tension test) and the associated micromechanisms of fracture. Results show how the…
This paper describes an experimental study developed to characterize the mode I and mode II fracture toughness of carbon/epoxy woven composites, using DCB and ENF tests, respectively. The laminates were manufactured using an epoxy resin…
The structural integrity and reliability of glass components are key issues for concentrated solar power (CSP) systems. For example, the glass windows in a solar furnace may suffer catastrophic fracture due to thermal and structural…
Crack propagation in gears is a problem related not only to the life of the components, but also to the concept of failsafe design. Fail safe design means to design a component in order that, if a failure occurs, this may cause a “safe…
In recent years, mechanical property of many SMA has improved in order to introduce these alloys in specific field of industry. Main examples of these alloys are the NiTi, Cu-Zn-Al and Cu-Al-Ni which are used in many fields of engineering…
In the last decades, damaging micromechanisms in ductile cast irons (DCIs) have been widely investigated, considering both the matrix microstructure and the loading conditions influence. Considering the graphite nodules, they were…
In recent years the implementation of the electric engine in the automotive industries has been increasingly marked. The speed of the electric motors is much higher than the combustion engine ones, bringing transmission gears to be…
Several studies have been carried out until now by various Research Agencies and Railway Administrations to quantify the effects of the track-bed geometrical characteristics on the transverse strength of the track. Unfortunately, not all…
During an earthquake, the nonlinearity of the bridge structure mainly occurs at the supports, bridge piers and restrainers. When entering nonlinear stage, members of the bridge structure affect the elasto-plastic seismic response of the…
Haimenkou site is the largest railing-enclosed wooden architecture settlement site on the waterfront in current China. This research conducts degradation assessment of waterlogged wood at Haimenkou site with various methods, including…
To compensate for the poor quality of thick-plate blanking parts in cross-section, this paper suggests using the optimizing bilateral ring gear holder parameters to increase burnish zone and improve cutting precision. With the bilateral…
Marble conventional triaxial loading and unloading failure testing research is carried out to analyze the elastic strain energy and dissipated strain energy evolutionary characteristics of the marble deformation process. The study results…
Earthquake action is the main external factor which influences long-term safe operation of civil construction, especially of the high-rise building. Applying time-history method to simulate earthquake response process of civil construction…
The method aims to recognize and extract the characteristic parameters of bridge cracks based on images of the cracks obtained through the application of preprocessing technologies, such as graying, graphical enhancements, spatial…
This paper primarily aims to introduce different stiffness ratio requirements for hospital buildings of various structural styles, to achieve a new standard. The requirements of each stiffness ratio are analyzed, according to the…
In this paper Digital Image Correlation (DIC) is used to study the evolution of the plastic zone close to a crack tip. A modified CT-specimen was used in order to fulfill the plane stress condition. The strain field around the crack tip…
This work deals with the notch sensitivity of sharp notches under multi-axial fatigue loading. The main discussion concerns the differences in notch sensitivity at high cycle fatigue regime, between tensile, torsional and combined loading.…
Nowadays, many components and structures are subjected to fatigue loading with a number of cycles higher than 107. In this scientific work, the behaviour of two kinds of tool steel was investigated in very high cycle fatigue regime. The…
In the present paper, testing methods currently adopted to measure the in service ballast resistance are synthetically reviewed to identify the main sources of uncertainty influencing the test loads and to define an experimental…
In the present paper the design and construction choices of a test field for the ballast lateral resistance measurement, in order to produce data useful for the development of a numerical model able to simulate the service critical…
