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Fatigue failures are a concern for old riveted steel bridges since most of them were not originally designed taking into account fatigue. The usual fatigue assessment approach for riveted joints consists of using the fatigue class 71 S-N curve proposed in Eurocode 3, part 1–9. However, this approach may lead to excessive conservative predictions since it is applied indistinctly for different riveted connection geometries and materials. Riveted joints fatigue classification according to the proposal of Taras and Greiner produce more consistent description of the experimental data rather than the Class 71 S-N curve as proposed in the EC3. Local approaches are an alternative methodology to perform fatigue characterization of any type of joints, made of any material, providing that material fatigue properties are available as well as accurate numerical models of the joints. This paper presents an experimental campaign and a numerical analysis concerning down-scale riveted specimens. The fatigue behaviour of these riveted joints was also modelled using standard and extended finite element methods. The different models produced diverse predictions, depending on the failure modes considered.

In this paper, the failure probability of corroded pipelines made by X60 steel grade is evaluated. For this complex real engineering failure problem, the burst corroded performance function is developed using an M5Tree model based on calibration with real burst test database. In addition statistical analysis of ILI-report data is conducted for best modeling of corrosion defects geometries (i.e. defects length and depth) based on Anderson-Darling statistic where different PDFs (i.e. Normal, Lognormal, Frechet, Gumbel, Weibull) were tested. Moreover, the effect of defects geometries on the failure probability of the case-studies were investigated for various operating regimes. Then the influence of distributions on the reliability analysis were also illustrated. Results indicated that increases in defects depth are strongly reduced the safety levels of this problem, where miss-selection of defects distributions could lead to conservatives results.

In this paper, the problem of fatigue crack growth resistance and fracture toughness in steel structural components have been discussed. For investigation were extracted parts of bridges made of 19th century puddled steel and early 20th century mild steel. The object of interest of the authors were fragments of steel structures from ancient bridges located in Warsaw (Poland): Most pod Cytadelą (marked as “C” material); Most Kierbedzia (marked as “W”); and, a parts from the Main Railway Station hall in Wroclaw, Poland (marked as “B”). In all cases, the metallographic analyses were performed. It has been proofed the presence of degradation processes in such old steel. The mentioned processes consisted mainly in precipitations of the brittle phases inside the ferrite grains, as well on the grain boundaries. The mechanical properties and crack growth resistance, as well as fracture toughness expressed by the J-integral method have been determined for the specimens collected from the Main Railway Station hall in Wroclaw (Poland). It has been shown that crack resistance – expressed with the critical value of J-integral – in the rolling direction is significantly higher than in the direction perpendicular to rolling. For fatigue analysis, fatigue crack growth experiments were performed for all materials in rolling direction as well as in transversal direction. Based on the experimental results is worth to notice that, the obtained values are far lower than the critical values of the J-integrals characterizing the modern low-carbon constructional steels (S235JR or S355JR steels).

In the context of fatigue evaluation of riveted railway bridges, cross-girder to main beam connections are frequently critical details. Secondary effects, such as out-of-plane bending and dynamic amplifications due to the proximity to loading paths which in the case of old bridges were not taken into account in the original design, may lead to severe increase of fatigue damage. The fatigue assessment of old riveted railway bridges has been addressed in the last years by developing local models of critical riveted joints that are linked to global models. This local-global modelling approach aims at evaluating local secondary stresses. Former fatigue probabilistic analyses of riveted joints have been focused on resistance variability rather than on loading/stresses (actions) variability. In this paper a probabilistic procedure to include the variability of loading in the fatigue analysis of complex riveted joints of railway bridges is proposed assuming loading as a random variable. Local finite element models were developed and later coupled with the global model in order to obtain the real stresses associated to real trains crossing the bridge. To reduce computational time, the results obtained from these local models were inputted in a Linear Fracture Mechanics model, supported by Paris fatigue crack propagation law. Monte Carlo simulation technique was applied to calculate the fatigue reliability of an old riveted railway bridge, considering traffic records from previous studies on the bridge.

Wire arc additive manufacturing (WAAM) has increasingly attracted attention in the construction sector because of its ability to produce large metallic structural parts in short times. In this paper, Coffin-Manson and Morrow (CMM) equation is employed to compare the fatigue life of WAAM stainless steel with the structural steels S355 and S690. The results showed that the fatigue performance of structural steel is better than the WAAM stainless steel, the fatigue performance vertical to printing direction (WAAM-900) is better than it along the printing direction (WAAM-00). In addition, the fatigue cycle of the transition reversals of structural steel is much less than it of WAAM stainless. With the increasing the fatigue cycle, the maximum density of the strain amplitude ratio is gradually increased to 1.0. The probabilistic parameters of CMM equation were obtained by a stochastic analysis using Latin hypercube sampling strategies. The probabilistic strain-fatigue life behaviour obtained from the constant exponent sampling strategy is higher when compared with the varied exponent sampling strategy for both WAAM stainless and structural steels.

Single shear lap joints have been a common method to fasten steel plates in railroad bridges and can be highly susceptible to fatigue cracking under the cyclic loading bridges experience. To better comprehend the fatigue process of these connections, it is important to understand the stress state near the rivet hole. While the fatigue behavior of these riveted connections has been studied, few have been carried out on stress distribution and crack formation in riveted lap joints fastening thick steel plates. This study is to provide information regarding the stress distributions developed in a single shear lap joint connecting plates of varying thicknesses. Results from the stress contour analysis are utilized to detect possible regions for fatigue crack nucleation under cyclic heavy axle loads. The study also provides information regarding the fatigue crack geometry typically found in single shear lap joints.

The 1st Virtual European Conference on Fracture (VECF1) has gathered more than 300 researchers from all over the world. They have presented more 320 papers, including 9 plenary lectures in the scope of the main VECF1 topics. Starting with 1800 views on the first day, there were 9300 views in the “hottest period” (June 20–July 2), making this event a great success. Conference was organized through number of Symposia, managed by ESIS Technical Committees. In the scope of these topics number of papers dealt with damage, cracks and related failures, including large structures like bridges, aircrafts, pressure vessels, large rotational equipment, pre-stressed and reinforced concrete constructions. As guest editors, we hope the Damage, Cracks & Failure Special Issue provides a remarkable impact in the research related to residual life assessment, modelling of failure and crack growth analysis. We also would like to express our gratitude to all authors for their contributions and to all reviewers for their generous work to guarantee the excellence of the papers. Finally, the guest editors would like to express a special thanks to Professor Richard Clegg, Editor-in-Chief of Engineering Failure Analysis journal, and to Elsevier staff for their support during the preparation of this issue.

Made available in DSpace on 2022-04-28T19:42:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-10-01 The fatigue crack initiation and propagation phases have been widely studied by the scientific community. There are several models to describe low-cycle fatigue behaviour based on strain damage criteria, but the most widely used is the Coffin-Manson-Morrow relationship, normally used for the fatigue crack initiation modelling. In addition, strain-life models based on hardness measurements and monotonic properties of metals have also been suggested. There are also integrated fatigue models that describe both the fatigue crack initiation and propagation phases, such as the UniGrow, Huffman, Peeker, among others, where the concept of successive crack re-initializations (increments) based on local approaches is adopted. In this paper, the low-cycle fatigue modelling based on Huffman approach using the strain energy density and considering dislocations density is investigated and discussed. For this, various methodologies to evaluating low-cycle fatigue strength based on Huffman approach and exploring different dislocation density parameters are suggested: (i) critical dislocation density driven by the highest strain amplitude; (ii) the mean value of the dislocation density of the available experimental fatigue data and, (iii) Monte Carlo (MC) stochastic prediction considering the variability of dislocation density and the cyclic strain hardening coefficient. Besides, the Monte Carlo stochastic simulations for obtaining the strain-life parameters, fatigue strength and ductility coefficients, it allows the generation of probabilistic fields for the low-cycle fatigue behaviour of metals. In this research, the experimental fatigue data of 1050, 6061-T651, and AlMgSi0.8 aluminium alloys are used to apply the suggested methodologies. A comparison between the experimental fatigue data and strain-life curves based on various suggested methodologies is made. Mechanical Engineering Department São Paulo State University (UNESP) School of Engineering, Av. Brasil Sul, 56 – Centro CONSTRUCT Faculty of Engineering University of Porto, Campus FEUP Faculty of Mechanical Engineering Department of Mechanics Materials and Biomedical Engineering Wroclaw University of Science and Technology INEGI Faculty of Engineering University of Porto, Campus FEUP Department of Mechanical and Industrial Engineering Norwegian University of Science and Technology (NTNU) Mechanical Engineering Department São Paulo State University (UNESP) School of Engineering, Av. Brasil Sul, 56 – Centro

Fibre Reinforced Polymer (FRP) composites can provide efficient enhancements in terms of strength and deformability for concrete structures, in which accurate predictions of FRP confined concrete ultimate conditions is highly essential to maintain safety levels, further structural analysis and members design. In this paper, three novel hybrid intelligence models were proposed based on the hybridization of Support Vector Regression (SVR) model with three bio-inspired optimization algorithms as genetic algorithm (GA), particle swarm optimization (PSO) and Whale optimization algorithm (WOA) for predicting the ultimate conditions of FRP-confined concrete. Moreover, 15 existing empirical relations for the prediction of the ultimate strength and strain of FRP-confined concrete have been comprehensively reviewed. The performances of the empirical models and the proposed hybrid models as SVR-GA, SVR-PSO and SVR-WOA are evaluated and compared based on a large database, including 780 circular FRP-confined concrete specimens, which are collected from the open-source published experiments. By comparing the predicted results based on several statistical indicators, the proposed hybrid SVR-models are generally outperforming the existing empirical relations in terms of accuracy and agreement with the experimental database. SVR-WOA provides superior performances than SVR-PSO, SVR-GA and all existed empirical models. The root mean square error is improved using SVR-WOA by 0.9%, 14.9 % and 37% for the ultimate strain capacity, and 2.7%, 4.6% and 17.3% for the ultimate strength compared to SVR-PSO, SVR-GA and the best empirical relation, respectively.

Elastomers are considered to be a popular vibration damping material for mechanical vehicles. Rubber components are the most commonly used - mainly due to their price. Competing solutions are PUR (Rigid Polyurethane) materials The results of investigations of polyurethane materials in various hardness configurations are presented in this paper. The main attention was paid to tearing and fracture tests using the EWF (Essential Work of Fracture) concept. Significant differences in the behaviour of materials with different stiffnesses expressed as 80ShA and 90ShA hardness were demonstrated. All obtained results were compared to competing materials such as rubbers, also of similar hardness. Each time, higher tear and fracture toughness were significantly exhibited by PUR.

A general procedure for fatigue life prediction of structural details based on Fracture Mechanics approach is presented in this paper, taking advantage of the new normalized fatigue crack growth model proposed by Castillo et al., here denoted as CCS model. An extension to the CCS model is proposed by adopting the cyclic J-integral range instead of the stress intensity factor range as reference parameter. This enables the generalized elastoplastic conditions resulting for the cracked geometry of the structural detail to be considered by means of the cyclic J-integral values obtained from a finite element analysis, for different loading levels and crack lengths. As a practical application, the proposed approach is applied to a notched plate made of P355NL1 steel, using the equivalent initial flaw size (EIFS) concept. Fatigue crack growth data for CT specimens from the literature is evaluated to estimate the modified CCS crack growth model parameters. The predicted fatigue propagation lifetime prediction is compared with the results and, finally, the goodness of the predictions is analysed and deviations discussed.

The maintenance and safety of ancient bridges is a major concern of governmental authorities. In particular, the safety of old riveted bridges fabricated and placed into service at the end of the 19th century deserves particular attention. These structures are susceptible to exhibit high fatigue damage levels due to their long operational period with increasing traffic intensity associated to an original design not covering the fatigue phenomenon. This paper reviews recent fatigue behaviour investigations on single and double shear riveted joints performed by Universities of Porto (Portugal), Tras-os-Montes e Alto Douro (Portugal), and Wroclaw (Poland), in particular concerning the fatigue characterization of riveted joints extracted from representative Portuguese riveted bridges, namely the Eiffel, Luiz I, Fao, Pinhao and Trezoi bridges. In order to overcome the influence of scatter and establish a reliable assessment for the obtained experimental data, two statistical approaches were used: implement linearized boundaries following the recommendation in ASTM E739 standard and defining probabilistic S N fields using the Castillo & Fernandez-Canteli model. This statistical analysis allows to propose design S N curves for single and double riveted joints and evaluate the applicability (safety) of using the design curves suggested in Eurocode 3 as well as design curves proposed by Taras and Greiner.

The paper presents the results of experimental research on polyurethane materials used in car suspension systems. Taking into account the frequency of maintenance and the number of replacement metal-rubber bushings on the market, the authors considered it reasonable to carry out their tests of materials with different hardnesses of 80 and 90 ShA used in conventional applications as well as in sports vehicle suspensions. Two types of PUR material were produced for this purpose. The materials were subjected to mechanical tests; tearing, tensile, compression, abrasive wear. Finally, a model of the polyurethane bushing was created and subjected to fatigue tests. As a result, several significant findings were made regarding the influence of hardness on selected mechanical properties. As evidenced by the results of the investigations, even a small increase in material hardness significantly affects changes of fatigue parameters and material fracture-related parameters in general. The pilot results can serve as reference values in the design of anti-failure bushing systems.

There are many old riveted bridges constructed 100–150 years ago around the world. In Portugal, it is counted that about 100 riveted bridges, which were built based on traffic intensity and vehicle weight, are no longer suitable nowadays. However, mainly due to economic reasons, those riveted bridges are still in service. Thus, the remaining performance is suggested to be accurately evaluated to determine possible repairs. However, the fatigue performance investigation of such riveted joints in old bridges is relatively limited. Then, fatigue assessment concerning the riveted joint is not contemplated in the current standard as EC3. This paper presents an experimental campaign of riveted joints. Three types of riveted connections are conducted to obtain the fatigue behaviour. Then experimental results, and its design curves obtained based on the ASTM E739 standard, are compared to S-N design curves, suggested for riveted connection. The fatigue strength predicted from class 71 in EC3 is lower than it obtained from test results.

Multiaxial stresses are usually present in engineering structures and are often associated to multiaxial fatigue failures. However, multiaxial fatigue is an open topic, full of questions and different points of view. Therefore, an experimental campaign of uniaxial and multiaxial fatigue tests under proportional loading was conducted aiming at evaluating the multiaxial fatigue behaviour of S355 structural steel in the high-cycle fatigue regime. Five different multiaxial models were used and evaluated, namely the Sines, Findley, McDiarmid, Dang Van and Susmel-MWCM. Each of them was applied to experimental data and the mean fatigue curves obtained from it were evaluated and compared. The coefficients present in each model definition were studied and determined through different methods. The Dang Van’s multiscale approach and Susmel model showed great accuracy in the description of the fatigue behaviour of the S355 steel, providing the best correlation of the uniaxial and multiaxial experimental data.

A linear-elastic Fracture Mechanics approach is used to estimate the fatigue life of riveted connections present in railroad bridge built-up steel girders under variable amplitude loading. Special care has been taken to analyze the effect of thermal clamping stresses on fatigue life. The analysis is developed using the variable amplitude stresses generated due to a traversing heavy axle train on a simply supported girder. Stress intensity factors for quarter elliptical corner crack emanating from a through-thickness (rivet) hole under remote tension were used. Thermal clamping stress, typically generated during the installation process, was quantified through a finite element simulation. Superposition principle was utilized to account for localized clamping stress present on the base material along with remote tension. Fatigue life estimations calculated using a linear-elastic Fracture Mechanics approach with and without considering clamping stress are compared. Finally, crack growth proved to be different under the effect of localized clamping stresses when compared to a crack growth emanating from a hole with no clamping stress.

In order to reduce the economic costs of pipeline construction projects and for offering a good combination of strength and toughness for efficient transportation of large quantities of hydrocarbon products under high pressure, High Strength Steels (HSS) such as API 5L X70 to X120 are used recently in the construction of pipeline systems for the large oil and gas projects. The commonly utilized models for the reliability evaluation of the HSS pipelines may lead to some conservatism regarding the used data. This paper aims to evaluate the system reliability of HSS pipelines with combined corrosion and cracks defects. Therefore, two failure modes as the plastic collapse and fracture are considered. The effect of different correlations under the term of the strain-hardening exponent that depends on the yield to ultimate tensile strength (Y/T) ratio is investigated. The reliability index of HSS pipelines is evaluated separately for each failure mode using the subset simulation technique. Herein, the tensile strength proprieties of the HSS pipelines are taken into consideration, while the applied methodology utilizes novel probabilistic models to predict the burst pressure for the plastic collapse failure mode. The steels toughness is taken as equal to the minimum requirement for both the ductile and the brittle fracture arrest applied in the HSS pipelines. Moreover, the reliability of the system with multiple failure modes is evaluated to show the mutual existence effect of crack and corrosion defects on pipeline safety.

The paper presents the fatigue tests results of the different samples configurations subjected to the biaxial type of loading. All test were performed for structural steel. The experimental campaign was conducted with non-proportional bending and torsion without and with phase shift equal to ϕ = 0° and 90° for various stress ratios. One-sided restrained samples were tested under constant load and constant stress ratio R = −1. The development of fatigue cracks was also observed and recorded during the tests. Stress distributions were numerically calculated using the Matlab program. Lifetimes calculated according to modified Huber-Mises, modified Tresca and Nishihara-Kawamoto criteria are compared with experimental ones.

Cumulative fatigue damage is a continuous and irreversible process that refers to the degradation of the component mechanical properties under cyclic loadings. In this work, using the concept of isodamage curves, a new non-linear fatigue damage accumulation model is proposed to account for fatigue damage evolution under multiple load levels. In particular, a computational process is established in which the isodamage curves converge into one point due to the exhaustion of static toughness. Experimental data of five materials are used for model validation and comparison. Results indicate that the proposed model provides better life predictions than the other four models.

FBG sensors are often packaged within composites before they are pasted on the blade surface, and many studies have shown that the materials, fatigue properties, geometric parameters, etc. of intermediate layer have influences on the measuring accuracy of the FBG sensors. Thus, this paper established an reliability calculation model based on strain transfer efficiency for the measuring accuracy of FBG sensors packaged by composites, analyzed the influences of material properties and geometric parameters of the adhesive layer on the performance of FBG sensors based on finite element analysis (FEA) method, and then compared the differences of strain transfer efficiency and reliability of the FBG sensors under different load conditions. The results show that the bond length and the bond thickness of the adhesive layer have greater influences on the performance of the FBG sensors compared with other parameters, both the strain transfer efficiency and the reliability of the FBG sensors will reduce over time under suddenly applied load and increase with increasing frequency of the alternating load.

Fatigue failures are of concern for steel bridges due to the likelihood of the steel to deteriorate under variable stresses. Residual life calculations of existing bridges in operation should take into account fatigue as a progressive damaging mechanism. A consistent residual life prediction should be based on actual fatigue data from bridge members to assess. This paper presents strain-life and crack propagation fatigue data obtained using samples of original material removed from five Portuguese metallic riveted bridges. While four of the analysed bridges are centenaries, the younger bridge is little more than 50 years old which is likely one of the last metallic bridges built in Portugal using the riveting technology. Besides the fatigue properties, the monotonic and cyclic elastoplastic properties are assessed for the samples of materials. From the analysis of the results it is clear that the older materials are puddle iron, a precursor of the modern construction steels, the latter being used in the younger bridge. The generated data is essential for residual fatigue life estimations considering both crack initiation and propagation phases, respectively in the framework of Local Approaches to fatigue and Linear Elastic Fracture Mechanics.