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To substitute for a traditional replication technique, an in-situ fatigue crack observing system for rotating bending testing machine has been newly developed. For verifying performance of this observing system, fatigue tests were carried…
The work is devoted to experimental study of heat flow evolution at the fatigue crack tip during biaxial loading. The plane samples of titanium alloy Graid-2 with thick of 1 mm were weakened by notch to initiate fatigue crack at the center…
Experimental and numerical studies investigating fatigue crack growth were conducted on flat samples made of stainless steel AISE 304 and titanium alloy Grade 2. The heat flux from the crack tip caused by plastic deformation localization…
The structures in service are subjected to loads whose amplitude varies most often over time. These differences in loading cycle levels will have a direct impact on the propagation of cracks that can lead to accelerations or slowdowns in…
This paper presents a study on the tensile, fracture, damage, and reliability properties of 3D printed polylactic acid (PLA), based on a series of experiments. The study focuses on polylactic acid (PLA) samples produced using fused…
Simulating the concrete fracture unlike other elastic and brittle materials quite different due to its quasibrittleness. The present research focussed on assess softening behavior by varying different fractions of aggregates and cement…
In Portugal there is a number of old metallic riveted railway and highway bridges that were erected by the end of the 19th century and beginning of the 20th century, and are still in operation, requiring inspections and remediation…
The reduced state of stress triaxiality observed in shallow cracked components allows an increased capacity to resist crack propagation compared to that observed in deeply cracked specimens. This may be regarded as a higher fracture…
The variation of crack shape factor (a/c) during propagation has an important role on calculation of the stress intensity factor (SIF), where imprecise estimation of this latter can lead us to an inaccurate prediction of failure…
In-service fatigue cracking of turbine disks of EI698 superalloy is discussed based on crack growth analyses. In the bolt joint for disks to shaft connecting there is high level of stress-state, which directed to earlier in-disks fatigue…
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…
Mechanical components fabbricated with quenched and tempered steels, exhibiting mixed microstructures as derived from slant quench conditions, are frequently encountered in the industrial practice, owing to a tendency to employ quite low…
In this work two different titanium dental implants are analyzed in order to evaluate their mechanical strength. An ad-hoc designed experimental apparatus is prepared to test against fatigue these implants in a way that approximates as…
This study has used the strain energy density (SED) approach to evaluate the stress intensity factor (SIF) of cracked cruciform welded joints in Hardox 450 steel. A microstructural analysis was made of Hardox 450 steel which is composed of…
While Additive Manufacturing (AM) of polymers has matured from rapid prototyping to functional production, the layer-wise fabrication process introduces significant mechanical anisotropy and microstructural heterogeneity, which complicates…
Adding fibres to concrete provides several advantages, especially in terms of controlling the crack opening width and propagation after the cracking onset. However, distribution and orientation of the fibres toward the active crack plane…
Shape memory property characterizes the behavior of many Ti based and Cu based alloys (SMAs). In Cu-Zn-Al SMAs, the original shape recovering is due to a bcc phase that is stable at high temperature. After an appropriate cooling process…
This work is devoted to the comparative analysis of three techniques for measurement of energy dissipation in metals under fatigue crack propagation: original contact heat flux sensor, post-processing of the infrared thermography data and…
Magnesium (Mg) alloys are attractive as structural materials due to their light weight and high specific strength. It is well known that Mg alloy has hexagonal close-packed (HCP) structure and only basal slip or twinning can operate during…
The theory of critical distances (TCD) has been applied to predict notch-based fracture and fatigue in a wide range of materials and components. The present paper describes a series of projects in which we applied this approach to human…
The work is devoted to the experimental study of heat dissipation process caused by fatigue crack propagation. To investigate a spatial and time temperature evolution at the crack tip set of experiments was carried out using specimens with…
Cracking direction in multiaxial low cycle fatigue is an important research subject because crack initiation and propagation behavior is a physical background for developing an estimation method of multiaxial low cycle fatigue lives.…
Blades of combustion turbines are extremely loaded turbojet elements, which transmit operative energy onto a rotor. Experiences of many years indicate, that cracks initiation and propagation in the blades during the operation time can…
Two cracks, initiated from the opposite tips of a central notch inclined by 45°, were considered in cruciform specimens made of Ti6246. A static load was applied to a cruciform arm while a cyclic load was applied along the other arm.…
A mixed-mode geometry has been chosen to investigate a crack propagation using the multi-parameter fracture mechanics concept. The so-called Williams’ series expansion is used for the crack-tip stress field approximation. It has been shown…
The use of miniaturized specimen testing methods is a promising way to solve the problem of limited materials in RPV monitoring programs. The use of miniature specimens allows the evaluation of fracture toughness from other specimen…
Some numerical studies of crack propagation are based on using constitutive models that account for damage evolution in the material. When a critical damage value has been reached in a material point, it is natural to assume that this…
The monitoring of a heat dissipation process can give an important information about kinetics of deformation process and current crack propagation rate. The work is devoted to the theoretical and experimental study of the problem. The…
The study presents and compares an application of two procedures to identify the crack tip location in PVC Sent samples under a uniaxial tensile test based on the image processing method. An IDS camera captures several photos of the PVC…
Due to their severe operating conditions, many industrial components are subjected to complex combinations of cyclic mechanical stresses and thermal pressures. These combinations are responsible for the initiation and propagation of…
The goal of this work is to improve the understanding of the relation between the microstructural characteristics of Intercritical Austempered Ductile Cast Iron (IADI) and the damage micromechanisms observed during its tensile loading. The…
Europe has a number of ancient riveted metallic bridges, constructed during the second half of the 19th century up to the middle of the 20th century, which are still in operation. In this paper, a unified approach is presented to generate…
Ultrasonic fatigue tests were carried out on stainless steel AISI 316 and 304, under two modalities: at room temperature and in immersion (water for 316 and antifreeze for 304 steels); all tests were carried out with a loading ratio R=-1.…
Austenitic stainless steel (JIS-SUS304L) with a bimodal harmonic structure, which is defined as a coarse-grained structure surrounded by a network of fine grains, was fabricated using powder metallurgy to improve both the strength and…
Since the last two centuries, concrete has become the number one building material in the world. Therefore, we are interested in studying the mechanical behavior at failure of this material and calculate its toughness. In this paper, we…
In the present work, the fracture resistance of a carbon fiber composite under mode I and mode II loading have been experimentally determined. For the mode I and II, the energy release rate G has been determinate for each material. In some…
In this paper, an experimental procedure to evaluate the elastic-plastic J-integral at the tip of a fatigue crack is presented. According to this new approach, the elastic component of the J-integral is derived from Thermoelastic Stress…
This paper discusses the application of machine learning techniques, notably artificial neural networks (ANN), in the fracture analysis of semi-infinite elastic plates with edge cracks. The Stress Intensity Factor (SIF) model for a…
The work reviews some preliminary recent micromechanical tests aimed at the evaluation of the fracture toughness of silicon. Pre-cracked nano specimens and alternatively notched nano specimens combined with the theory of critical distances…
Most of the prior studies on the prediction of fatigue lives have been limited to uniaxial loading cases, whereas real world loading scenarios are often multiaxial, and the prediction of fatigue life based upon uniaxial fatigue properties…
The investigation of low-cycle fatigue behaviour of lotus-type porous material is presented in this paper. Porous materials exhibit some unique features which are useful for a number of various applications. This paper evaluates a…
A present study reveals the influence of nano Al2O3 and ZrO2 reinforcements on the fracture toughness of Hybrid Metal matrix Composites (HMMCs) made of Al6061 alloy. Composites are synthesized by varying weight fraction of alumina and…
This study reports an experimental investigation of the fatigue and fracture resistance of R350HT, a heat-treated pearlitic rail steel with refined microstructure used in rails. Monotonic tensile, rotating bending, linear elastic plane…
Ultra-high-strength steels (with tensile strength higher than 980 MPa) are widely used in automobile manufacturing owing to their lightweight that contributes to fuel efficiency. The fatigue strength of ultra-high-strength steels with a…
The compliance method was first applied to short rod specimens to determine the nonlinear fracture toughness of rock materials by ISRM (International Society for Rock Mechanics) in the 1980s. In this study, utilizing the techniques of the…
This work deals with investigations of the stress field distribution around a steel anchor embedded in a concrete. Tensile loading - pulling force of the steel anchor is considered, which is very often connected to concrete cone failure.…
Cracks in clayey soil cause a reduction in the seismic loading capacity which can lead to structural failures. Seismic acceleration is the primary cause of crack propagation and damage to the earth's structure. This study investigated the…
Metallic structural components, placed in contact with other bodies while experiencing vibrations in operating conditions, are susceptible to fretting, which can have a significant impact on their fatigue performance. Although extensive…
In this work, the effects of natural particles on the micro failure mechanisms and static strength of an epoxy are studied using scanning electron microscope (SEM) technique. To this end, bulk specimens and adhesively bonded single lap…
This work presents an in-depth study of the low-cycle fatigue behaviour of ferritic-pearlitic HSLA-420 high-strength steel sheets, with emphasis on the influence of loading direction on fatigue life and damage mechanisms. Plastic…
