https://www.fracturae.com/index.php/fis/issue/feed Frattura ed Integrità Strutturale 2021-03-01T06:57:52+00:00 Francesco Iacoviello iacoviello@unicas.it Open Journal Systems <p>Frattura ed Integrità Strutturale (Fracture and Structural Integrity) is the International Journal of the Italian Group of Fracture (ISSN 1971-8993). It is an open-access journal published online every three months (January, April, July, October). <br />Frattura ed Integrità Strutturale encompasses the broad topic of structural integrity, which is based on the mechanics of fatigue and fracture and is concerned with the reliability and effectiveness of structural components. The aim of the Journal is to promote works and researches on fracture phenomena, as well as the development of new materials and new standards for structural integrity assessment. The Journal is interdisciplinary and accepts contributions from engineers, metallurgists, materials scientists, physicists, chemists, and mathematicians.</p> <p><strong>More details:</strong></p> <p>- The Journal is financially supported by the <a href="https://www.gruppofrattura.it/">Italian Group of Fracture (IGF)</a> and by crowdfunding. It is completely free of charge both for readers and for authors. Neither processing charges nor submission charges are required.</p> <p>- Papers can be published only after a preliminary plagiarism/autoplagiarism check and a blind peer-review process (two reviewers, at least). More than one reviewing rounds are possible.</p> <p>- The Journal is well indexed (e.g., Scopus, since 2012, and WoS, since 2015).</p> <p>- All the papers are published with their Visual Abstracts (2 minutes max videos with the "cores" of the papers). All the Visual Abstracts are available both in a dedicated <a href="https://www.youtube.com/channel/UC3Ob2GNW8i0phNiiKjEVv0A">YouTube channel</a> and in an "on demand" page (<a href="https://www.gruppofrattura.eu/journal/visual-abstract">LINK</a>). All the issues are also published in a browsable version (<a href="https://fis.cld.bz/Issues">LINK</a>).</p> https://www.fracturae.com/index.php/fis/article/view/3032 Effect machine parameters on surface topography and metal removal rate of carbon and alloy steel in Plano-milling machine 2021-03-01T06:57:52+00:00 Hiralal S. Patil hspatil12@rediffmail.com <p>The work presents performance analysis of converted Plano milling machine from planner machine. In experimental work, machining parametric optimization by Taguchi method has carried out on carbon steel IS2062 and alloy steel ASME SA387 with coated cemented tungsten carbide tip tool using Plano milling machine. The experiments analyses the influence of machine parameters like speed (rpm), feed (mm/rev) and depth of cut (mm) on surface roughness and metal removal rate. The surface characteristics and metal removal rate response for Plano milling operation were investigated by using L9 orthogonal array, signal-to-noise ratio and analysis of variance with Minitab software. In carbon steel, optimum machining parameters of 250 rpm, 1.42 mm/rev, and 1.5 mm gives optimum roughness value of 1.92 μm and optimal parameters 400 rpm, 1.42 mm/rev, and 1.5 mm gives optimum removal rate of 13.24´10<sup>-6</sup> mm<sup>3</sup>/min. Similarly in alloy steel A387, the optimum surface roughness of 2.31 μm were observed at 250rpm, 1.42mm/rev, and 1.5mm along with optimum removal rate of 18.8´10<sup>-6</sup> mm<sup>3</sup>/min at optimal parameters of 400 rpm, 1.42 mm/rev, 1.5 mm. From experimentation, it is observed that machine parameters have significant effect to enhance surface topography and metal removal rate of material while machining.</p> <p>&nbsp;</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3031 Free vibration characteristics of pre-stressed composite plate intended for strengthening pre-stressed concrete beams 2021-02-28T10:10:17+00:00 Baghdad KROUR krour.bag@gmail.com Khaled BENALI benali.kld@gmail.com Mohamed Atif BENATTA benat_atef@yahoo.fr Mohamed BACHIR BOUIADJRA mohamedbachirbouiadjra@gmail.com <p>Strengthening concrete beams by pre-stressed or not pre-stressed composite plates has become one of the widely used techniques in civil engineering in aim to improve durability of infrastructures specifically against seismic solicitations. However this type of reinforcement is quite new for pre-stressed concrete beams.&nbsp;</p> <p>Before using a composite plate for strengthening pre-stressed concrete beams, it is so important to know its vibration characteristics. In this paper an analytical model based on the high order and the laminate theories is proposed in order to well determine the free vibration characteristics of a pre-stressed composite plate.</p> <p>A parametric studies varying pre-stressing effort and fiber orientations are carried out in aim to find the best way to use the composite plate in the reinforcing of pre-stressed concrete beams.</p> <p>As an important result of this study, the pre-stressed composite plate procures interesting free vibration characteristics making it a good candidate for strengthening pre-stressed concrete beams.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3030 PARAMETRIC STUDY OF I-SHAPED SHEAR CONNECTORS WITH DIFFERENT ORIENTATIONS IN PUSH-OUT TEST 2021-02-26T18:32:09+00:00 Boursas Farid farid.boursas@univ-tebessa.dz Djamel Boutagouga d.boutagouga@yahoo.fr <p>Many researches have been carried out on connectors in order to optimize connector’s number and facilitate the assembly tasks and fixing on site as well as the economic side. This article presents the study of I-shaped connectors behavior under monotonic load welded in four different orientations in order to get the position which gives the high shear strength and the best ductility. For this purpose, eight push-out test specimens with I-shaped shear connectors with different orientations and dimensions were tested in C20/25 and C30/37 concrete classes. The load-slip behavior and failure modes of the tested connectors are presented and discussed. Furthermore, a non-linear 3D finite element modelling of the push-out test is performed in order to further investigate the influencing parameters on the I-shaped connectors behavior. Hence, a parametric study is carried out by using the established 3D finite elements model to study the influence of concrete strength, connector’s steel grade, reinforcements, height and length of the connector. Both experimental and numerical results show that there is a privilege orientation for which the shear strength of an I-shaped shear connector is significantly higher than that of all other tested orientations.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3029 Effect of multi-layer prosthetic foam liner on the stresses at the stump–prosthetic interface 2021-02-25T11:25:18+00:00 ismail boudjemaa ismailboubou000@gmail.com Abderahmane SAHLI sahliabderahmen@yahoo.fr Abdelkader benkhettou aekben.dz22@gmail.com Smail Benbarek sma_benbarek@yahoo.fr <p>The prosthetic liner plays a significant role in the redistribution of the pressure between the stump and the socket, as it adding a cushioning layer between the stump and the socket which relieves pain and makes the prosthesis more comfortable.</p> <p>This study employed nonlinear finite element analyses to investigate the peak pressure and shear stress at stump–prosthetic interface in the case of multi-layer prosthetic foam liner, this liner having an inner polymeric foam layer Surrounded by another type of polymeric foam layer, we used three different types of foams in different order to define this liner (flexible polyurethane foam, polyurethane-shape memory polymer foam, and natural rubber latex foam). That’s allows comparing 6 deferent configuration of multi-layer prosthetic foam liner.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3028 Mechanical properties and ductility of a concrete matrix reinforced with polypropylene and sisal fibers 2021-02-22T16:20:29+00:00 hassan suiffi suiffi@gmail.com Anas El Maliki a.elmaliki@ensem.ac.ma Omar Cherkaoui cherkaoui@esith.ac.ma Mohamed Dalal dalal@esith.ac.ma <p>In order to study the durability of cementitious composites with polypropylene fibers, several experimental tests were carried out. In this study, the durability was studied using three major indicators which can be summarized in: the porosity accessible to water ε<sub>b</sub>, the permeability to K<sub>app.gas</sub> oxygen and the D<sub>ns</sub> diffusivity. The porosity test was carried out to evaluate the absorption rate which remains significant compared to concrete without fibers; the chloride permeability test was carried out to assess the permeability of the concrete and the diffusivity test to determine the resistance of the composite to aggressive chemical agents. Test results revealed that all mixtures had low to very low chloride permeability. The increase in porosity for the different strengths with polypropylene fibers ranged from 1.50% to 3.75% compared to the reference mixture.</p> <p>For these durability tests, the composite was tested with different strengths of polypropylene fibers (0.05%, 0.10%, 0.30% and 0.50%). The results showed that the addition of polypropylene fibers in a cement matrix does not affect the durability of the composite which remains normal.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3026 Numerical Evaluation of Dynamic Responses of Castellated Steel beams and columns under Blast Loads 2021-02-21T22:24:02+00:00 mahmoud Nawar mn6w8@mail.missouri.edu Ibrahim Arafa engibrahimtalataat@gmail.com Osama Elhosseiny dr.ossama@bect.net <p>Beams and columns are probably the most susceptible structural elements in steel structures to terrorist attacks. Effects of web openings on the structural performance of steel members under flexure are more substantially complex than those with solid web I-sections under the diversity of blast loading scenarios. The intensive blast pressures create localized various failure modes in castellated steel beams and columns (CSMs) (Vierendeel mechanism, web-post buckling, and lateral torsional buckling). In this paper, the dynamic response of CSMs was numerically evaluated under different levels of blast damages using LS-DYNA software. Explicit finite element analysis was performed to investigate the effects of web opening shapes, boundary conditions and strengthening details on the blast resistance of CSMs. A conclusion of this study is that CSMs give a higher level of ductile responses to the different blast scenarios compared to those members with parent solid steel sections. However, the web opening shapes have slight effects on the global dynamic behavior of CSMs, the members with circular web openings have an effective enhancement to get higher ductility than other shapes. Furthermore, retrofitting using both closed holes at ends (Ch) and continuous vertical stiffener (Cvs) improved the dynamic performance due to high energy absorption capabilities.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3025 The effect of surface texturing in the sliding surface on tribological characteristics of alloy steel under wet condition 2021-02-20T06:35:07+00:00 Hiralal S. Patil hspatil12@rediffmail.com D. C. Patel pateldcp@gmail.com <p>Surface texturing plays a significant role on the tribological performance of contact surfaces. The tribological characteristics are mostly dependent upon the different pattern and methods of surface texturing. This research works investigates lubricated wear behaviour on circular dimples textured EN-31 alloy steel materials using DUCOM linear reciprocating tribometer. The surface dimples are fabricated by micro-EDM and micro-drilling CNC methods. Initially plane surfaces are tested under different lubricants ISO-68 and ISO-220 oil on a couple of EN31 plates with EN8 steel pin. At loading conditions the results clearly shows that the ISO 68 oil gives better performance than ISO-220 oil in terms of frictional force and COF. The operation during test under ISO-220 oil observed is very noisy and wear rate is also more. Then after experiments under different load conditions on textured surfaces were investigated using optimized ISO-68 oil. An experimental results on m-EDM provides superior frictional characteristics with respect to m-CNC. Surface texturing may act as wear debris trapper, lubricant reservoirs, hydrodynamic lift, and retarding the lubricant molecules flow in a particular path where potential exists. Here micro-dimples EDM surface textures can enhance mixed lubrication and in mixed lubrication the friction is least and this may leads to decrement of wear loss.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3024 The effect of surface texturing in the sliding surface on tribological properties of EN31 alloy steel under wet condition 2021-02-18T09:02:17+00:00 Hiralal S. Patil hspatil12@rediffmail.com <p>Surface texturing plays a vital role on the tribological performance of contact surfaces. The tribological characteristics are mostly dependent upon the different pattern and methods of surface texturing. This works investigates lubricated wear behaviour on circular dimples textured EN-31 steel by micro drilling-CNC and EDM processes using DUCOM pin-on-reciprocating plate tribometer. Initially un-textured samples are tested under different lubricants ISO-68 and ISO-220 oil on a couple of plates of EN-31 with EN-8 pin. At loading conditions the results clearly shows that the ISO 68 oil gives better performance than ISO-220 oil in terms of frictional force and COF. The operation during test under ISO-220 oil is very noisy and wear rate is also more. Later on experiments under varying load conditions on surface textured samples were investigated under slide-way ISO-68 oil. Micro EDM provides superior frictional characteristics as compared to micro-CNC. Surface texture has several advantages as it acts as lubricant reservoir, provision for wear particles and area for hydrodynamic action of lubricant. Thus it can be concluded that surface textures, here dimples, can enhance mixed film state of hydrodynamic lubrication. In mixed film state the friction is least, and this may be the reason for decrement of wear loss</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3023 Prediction of the temperature recorded in lap joint at during the friction stir welding of aluminum alloys 2021-02-16T18:40:11+00:00 abdelatif MIMMI abdelatifmimi94@gmail.com <p><strong>.</strong> &nbsp;This research aims to model parameters that affect temperature during friction stir lap welding joint (FSLW). The world of physical understanding is that influence on the temperature, microstructural refinement, material flow resulting and therefore fluid variations on the next mechanical properties of FSW butt lap joints of aluminum 6060 T5 Alloy is influenced by the geometry of pin geometry and material. In general, this numerical approach allowed us to optimize the parameter used for this form of welding (FSLW) such that the maximum temperature along the path of the instrument is reached through the application of a variance analysis strategy (ANOVA). The maximum temperature (207.012, ° C, 337.245 ° C) could be reached by using a joint rotational velocity (1999.99 rpm, 1892.29 rpm), welding velocity (203.698 mm / min, 216.167 mm / min) respective for A and B configurations.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3022 Computation of mode I strain energy release rate of symmetrical and asymmetrical sandwich structures using mixed finite element 2021-02-16T18:33:13+00:00 AMINA MOHAMED BEN ALI benaliamina21@gmail.com SALAH BOUZIANE bouziane_21@yahoo.fr HAMOUDI BOUZERD bib_ham@yahoo.fr <p>The use of composite materials is on the rise in different engineering fields, the main advantage of these materials for the aerospace industry is their low weight for excellent mechanical qualities. The analysis of failure modes, such as delamination, of these materials has received great attention from researchers. This paper proposes a method to evaluate the mode I Strain Energy Release Rate (SERR) of sandwich structures. This method associated a two-dimensional mixed finite element with virtual crack extension technique for the analysis of interfacial delamination of sandwich beams. A symmetrical Double Cantilever Beam (DCB) and asymmetrical Double Cantilever Beam (UDCB) have been analyzed in this study.&nbsp; The comparison of the results obtained by this method and those found in the literature shows efficiency and good precision for the calculation of Strain Energy Release Rate (SERR).</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3020 Prediction of the temperature recorded in lap joint at during the friction stir welding of aluminum alloys 2021-02-15T19:53:54+00:00 abdelatif MIMMI abdelatifmimi94@gmail.com <p>This research aims to model parameters that affect temperature during friction stir lap welding joint (FSLW). The world of physical understanding is that influence on the temperature, microstructural refinement, material flow resulting and therefore fluid variations on the next mechanical properties of FSW butt lap joints of aluminum 6060 T5 Alloy is influenced by the geometry of pin geometry and material. In general, this numerical approach allowed us to optimize the parameter used for this form of welding (FSLW) such that the maximum temperature along the path of the instrument is reached through the application of a variance analysis strategy (ANOVA). The maximum temperature (207.012, ° C, 337.245 ° C) could be reached by using a joint rotational velocity (1999.99 rpm, 1892.29 rpm), welding velocity (203.698 mm / min, 216.167 mm / min) respective for A and B configurations</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3019 Computation of mode I strain energy release rate of symmetrical and asymmetrical sandwich structures using mixed finite element 2021-02-15T17:49:47+00:00 AMINA MOHAMED BEN ALI benaliamina21@gmail.com <p>The use of composite materials is on the rise in different engineering fields, the main advantage of these materials for the aerospace industry is their low weight for excellent mechanical qualities. The analysis of failure modes, such as delamination, of these materials has received great attention from researchers. This paper proposes a method to evaluate the mode I Strain Energy Release Rate (SERR) of sandwich structures. This method associated a two-dimensional mixed finite element with a virtual crack extension technique for the analysis of interfacial delamination of sandwich beams. Asymmetrical Double Cantilever Beam (DCB) and asymmetrical Double Cantilever Beam (UDCB) have been analyzed in this study.&nbsp; The comparison of the results obtained by this method and those found in the literature shows efficiency and good precision for the calculation of Strain Energy Release Rate (SERR).</p> <p>&nbsp;</p> <p>&nbsp;</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3018 Beam damage detection by additional masses using optimizer 2021-02-14T03:36:59+00:00 Alaaeldin Elsisi elsisiae@missouri.edu Abdallah Salama eng_abdullah203@yahoo.com Atef Eraky ateferaky@zu.edu.eg <p>Dynamic characteristics have great interest to researchers in the damage detection field. The natural frequencies are distinguished from the other characteristics as it can be obtained with higher accuracy because it is less affected by noise. However, the limitation of using the natural frequency is that it is not sufficient alone in most cases to determine the depth and location of the damage. Additional masses can be added to different locations in structural element to change the natural frequencies, every change in additional mass location create new dynamic case with new frequencies. these cases can overcome the limitation of using single case natural frequency only. In this paper, the dynamic characteristic technique with additional masses was used to detect the damage in simple spans and two continuous, and three continuous spans beams with different damage scenarios. The grey wolf optimizer is used in this process due to its ability to provide very competitive results. Finite element analysis and MATLAB code were used to perform the optimization. The method was validated with experimental work. Several beam structures were tested by the validated technique. This method provides accurate results in the detection of both damage severity and location.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3017 Mixed Finite Element Method for Crack Analysis in Anisotropic Materials 2021-02-21T08:33:12+00:00 Sami Derouiche sami.derouiche25@gmail.com Salah Bouziane bouziane_21@yahoo.fr Hamoudi Bouzerd bib_ham@yahoo.fr <p>Composite materials are becoming widely essential due to the ease to manipulate their mechanical properties in order to obtain certain quality, achieve safety or a specific behavior. Those kind of materials are considered anisotropic because of the variety constituents contained, giving them the property of behaving differently in different direction.</p> <p>In this work, a special mixed finite element is adapted to evaluate the energy release rate of crack extension in anisotropic materials in two cases scenario; the first is with a kinking crack in a rectangular plat and the second is of a cracked edge rectangular plat with different axes orientations.</p> <p>The results obtained are in good concordance with the analytical results, making the proposed mixed finite element a good model and allow it to study much complicated cases in the future works.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3016 Impact of the adhesive and the composite material moist aging on the mechanical behavior of pre-cracked and reinforced beams. 2021-02-21T08:32:41+00:00 Laid Rezgani lairez1@yahoo.fr Mohamed Amine Errahmene errahmane.amine@gmail.com Kouider Madani koumad10@yahoo.fr Feaugas Xavier xavier.feaugas@univ-lr.fr <p>In this work, a numerical modeling is carried out by the finite element method on the mechanical behavior of reinforced concrete beams pre-cracked and strengthened with composite materials; the aging impact of the adhesive and the composite material by immersion in water on the effectiveness of reinforcement is investigated. The presence of water in the adhesive decreases the tensile strength and the elastic modulus but also increases the ductility of material. These changes in mechanical properties are more important when the duration of immersion in water increases. The evaluation of the stresses in the adhesive joint and in the beam showed us that moisture has a beneficial effect on this structure, the stresses at the adhesive joint decreases with increasing aging time, and that directly affects the rate of load transfer from the damaged area to the composite plate.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3015 Mixed Finite Element Method for Crack Analysis in Anisotropic Materials 2021-02-13T01:16:25+00:00 Sami Derouiche sami.derouiche25@gmail.com <p>Composite materials are becoming widely essential due to the ease to manipulate their mechanical properties in order to obtain certain quality, achieve safety or a specific behavior. Those kind of materials are considered anisotropic because of the variety constituents contained, giving them the property of behaving differently in different direction.</p> <p>In this work, a special mixed finite element is adapted to evaluate the energy release rate of crack extension in anisotropic materials in two cases scenario; the first is with a kinking crack in a rectangular plat and the second is of a cracked edge rectangular plat with different axes orientations.</p> <p>The results obtained are in good concordance with the analytical results, making the proposed mixed finite element a good model and allow it to study much complicated cases in the future works.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3013 Numerical Evaluation of Dynamic Responses of Castellated Steel beams and columns under Blast Loads 2021-02-10T06:50:07+00:00 mahmoud Nawar mn6w8@mail.missouri.edu Ibrahim Arafa engibrahimtalataat@gmail.com Osama Elhosseiny dr.ossama@bect.net <p>Beams and columns are probably the most vulnerable structural components in steel structures to terrorist attacks. Effects of web openings on the structural behavior of steel members under flexure are significantly more complex than the one of solid web I-shaped sections under the diversity of blast loading scenarios. The intensive blast pressures create localized various failure modes in castellated steel beams and columns (CSMs) (Vierendeel mechanism, web-post buckling, and lateral torsional buckling). In this paper, the dynamic response of CSMs was numerically evaluated under different levels of blast damages using LS-DYNA software. Explicit finite element analyses were carried out to investigate the effect of web opening shapes, boundary conditions and strengthening details on the blast resistance of CSMs. A conclusion of this research is that CSMs provide a higher level of ductile response to the different blast scenarios compared to those members with parent solid steel sections. However, the web opening shapes have slight effects on the global dynamic behavior of CSMs, the members with circular web openings have an effective enhancement to get higher ductility. Furthermore, retrofitting using both closed holes at ends (Ch) and continuous vertical stiffener (Cvs) improved the dynamic performance due to high energy absorption capabilities.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3011 E The seismic response of structural outrigger systems in tall building 2021-02-09T19:20:17+00:00 eman el-gharbawy em412019@gmail.com <p>One of the advanced structural systems that have been applied in tall buildings to improve the building strength during quake loads is the outrigger system. For that, this research is interested to study different structural system as a vierendeel system and wall beam system when applied them as outrigger which is connected between the internal core walls and the external columns in one or two stories. The outrigger position changed through the tallness of 40 story building and the building response is examined in this research under El-Centro time history earthquake load. All the models are analyzed in Midas-Gen program and the research conclusions were concluded to help researchers to provide more in the field of civil engineering. The inferred parameters as storey drift, story drift ratio and base storey overturning moment are plotted in graphs between the storey number and the outrigger position for each outrigger system. The results showed that, the one storey wall beam structural system is better than two stories vierendeel structural system when these systems applied as outrigger system. The best position for one storey outrigger is about 0.45 of the total building height and for the two stories outrigger, the .20 and .45 of the total building height are the best positions. Overall, the outrigger system is an effective structural system to make the tall buildings withstand through the earthquake loads.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3010 Effect of Different Reinforcement Configurations on the Behavior of RC Wide Beams 2021-02-09T20:53:50+00:00 Mohamed Husain mo_husain2000@yahoo.com Mahmoud A. El-Hak Khater Khater_civil@yahoo.com Basma Elsayed Helal basmaehm@zu.edu.eg <p>In this paper numerical analysis of wide shallow beams was carried out. Some beams were loaded with lateral load and other loaded vertical and lateral load. Different models of reinforced concrete of wide shallow beams were studied numerically via ANSYS platform and parametric study was conducted. Among the parameters, web reinforcement ratio, lower reinforcement ratio and upper reinforcement ratio. The value of parameters in lower reinforcement ratio (1.5%,1%,0.7%,0.3%) of cross-section area, upper reinforcement ratio (0.8,0.6,0.5,0.4) of the tensile reinforcement ratio and web reinforcement ratio (0.13 %,0.067%), the effect of these parameters on ductility, dissipation, toughness, stiffness, over strength, stress and strain. The results show that the studied parameter effects all these properties, the least ductility was noticed in the wide beam (B7) with a value of 1.1.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3009 Study of the Mechanical Behavior by Fatigue of a Cracked Aluminum Alloy Plate Repaired by different Composite Patch 2021-02-09T12:32:23+00:00 Moulgada Abdelmadjid amoulgada@hotmail.fr Ait kaci Djafar Aitkaci07@yahoo.fr Zagane Mohammed El Sallah salah_cao@yahoo.fr Sahli Abderrahmane sahliabderahmen@yahoo.fr Zahi Rachid zahirachid72@yahoo.fr <p>Our research based on the study of the fatigue behavior of an aluminum alloy plate, presenting a central crack, stressed in tension in its lower and upper part, several parameters have been highlighted namely, the effect loading with a charge ratio R = 0, then the effect of the charge ratio on the repaired and unrepaired plate by two composite patches which are boron / epoxy and graphite / epoxy, finally, the effect of the material of the plate over the life of the plate and compare the different materials</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3008 E The seismic response of structural outrigger systems in tall building 2021-02-03T10:08:23+00:00 eman el-gharbawy em412019@gmail.com <p>One of the advanced structural systems that have been applied in tall buildings to<br>improve the building strength during quake loads is the outrigger system. For that, this<br>research is interested to study different structural system as a vierendeel system and wall beam<br>system when applied them as outrigger which is connected between the internal core walls and<br>the external columns in one or two stories. The outrigger position changed through the tallness<br>of 40 story building and the building response is examined in this research under El-Centro<br>time history earthquake load. All the models are analyzed in Midas-Gen program and the<br>research conclusions were concluded to help researchers to provide more in the field of civil<br>engineering. The inferred parameters as storey drift, story drift ratio and base storey<br>overturning moment are plotted in graphs between the storey number and the outrigger<br>position for each outrigger system. The results showed that, the one storey wall beam<br>structural system is better than two stories vierendeel structural system when these systems<br>applied as outrigger system. The best position for one storey outrigger is about 0.45 of the<br>total building height and for the two stories outrigger, the .20 and .45 of the total building<br>height are the best positions. Overall, the outrigger system is an effective structural system to<br>make the tall buildings withstand through the earthquake loads.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3007 Effect of porosity on fracture mechanics in spot welds 2021-02-21T08:29:25+00:00 Imen Benala Blasius48@hotmail.com Leila Zouambi zouambileila@yahoo.fr Sardar Sikandar Hayat sikandariub@yahoo.com Bouafia Farida fbouafia2011@yahoo.fr Boualem Serier boualems@yahoo.fr <p>The stress intensity factor is the most important parameter in fracture mechanics. In this research work, we have been studied the effect of the defect (porosity) on the behavior of cracks initiated in a welded structure by spot welding three-dimensionally using the finite element method. This behavior is analyzed in terms of variation of stress intensity factors in opening mode and sliding mode. The effect of parameters such as the mechanical load, crack size, porosity form, porosity size, porosity-crack interaction, and crack orientation has been studied. This study is treated as a linear elastic fracture mechanics problem in mixed mode, under plane stress conditions.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3006 Development of mathematical model and optimization of GMA welding parameters of IS 2062 grade A steel weldments 2021-02-17T18:04:58+00:00 Saadat Ali Rizvi alisaadat@rediffmail.com Wajahat Ali Wajahatali@rediffmail.com <p>In this experimental works, the effect of GMA welding process parameters, such as arc voltage, wire feed speed, and gas flow rate on the mechanical quality of IS 2062 structural steel of grade A has been studied. Process parameters play an important role in determining the weld quality. In this research work response surface methodology (RSM) technique via design expert (DOE) 12 version software was applied to determining the weld quality and also to develop a mathematical model that can predict the main effect of the above said parameters on weld quality i.e. toughness and hardness. A set of experiments has been conducted to collect the data using a central composite design and ANOVA was used to predict the impact of welding parameters on toughness and hardness and Comparison also made between the actual result and predicted value and from the result that is clear that toughness and hardness of weldment is significantly affected by arc voltage, wire feed speed, and follow by gas flow rate.</p> Copyright (c) 2021 Saadat Ali Rizvi, Wajahat Ali https://www.fracturae.com/index.php/fis/article/view/3005 Development of mathematical model and optimization of GMA welding parameters of IS 2062 grade A steel weldments 2021-01-31T03:58:43+00:00 Saadat Ali Rizvi alisaadat@rediffmail.com <p>In this experimental works, the effect of GMA welding process parameters, such as arc voltage, wire feed speed, and gas flow rate on the mechanical quality of IS 2062 structural steel of grade A has been studied. Process parameters play an important role in determining the weld quality. In this research work response surface methodology (RSM) technique via design expert (DOE) 12 version software was applied to determining the weld quality and also to develop a mathematical model that can predict the main effect of the above said parameters on weld quality i.e. toughness and hardness. A set of experiments has been conducted to collect the data using a central composite design and ANOVA was used to predict the impact of welding parameters on toughness and hardness and Comparison also made between the actual result and predicted value and from result that is clear that toughness and hardness of weldment is significantly affected by arc voltage, wire feed speed, and follow by gas flow rate.</p> Copyright (c) https://www.fracturae.com/index.php/fis/article/view/3004 Experimental and analytical investigations of reinforced concrete beams strengthened by different CFRP sheet schemes. 2021-02-26T15:35:16+00:00 mahmoud madqour madqour42@gmail.com khaled fawzy khaled_lashen1@yahoo.com Hilal Hassan hilalcivil@yahoo.com <p>The use of bonded externally polymer reinforced fiber (FRP) Laminates has been introduced as an effective approach in rehabilitating (RC) structures due to their high strength, corrosion resistance, reduced weight, and ease of use. This paper discusses the experimental results of the flexural reinforcement of RC beams by CFRP sheets bonded by epoxy adhesive to the tensile surface of the beams. Using a four-point bending load system over an effective clear length of 1800 mm, a total of ten beams with an overall dimension of 150 * 200 * 2000 with different degrees of strengthening schemes were constructed and tested. A numerical study using ANSYS finite element program was conducted by modeling RC beams. The number of layers, strengthening scheme (side and U-shape bonding) and reinforcement ratio are the major parameters of the experimental study. the research indicate that the flexural strength of the beams was substantially improved as the layers of laminate increased between 31.80 and 71.50 % and using U shape in ends delaying or preventing debonding failure. The result obtained using ANSYS model showed acceptable agreement with the experimental results, with deviations varying no more than 10 % for all specimens.&nbsp;</p> Copyright (c)