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Fracture behavior of multi-layered composites under impact loading
, Article Materials Science and Engineering A ; Volume 448, Issue 1-2 , 2007 , Pages 20-24 ; 09215093 (ISSN) ; Bagheri, R ; Sharif University of Technology
2007
Abstract
In this investigation, aluminum layers are bonded together using epoxy adhesive. The adhesive is modified using different additives and the influence of adhesive composition on interfacial fracture energy is measured via double cantilever beam (DCB) test. To characterize the mechanical behavior of the adhesive, compression and impact tests were incorporated. The results of compression and impact tests show that compressive and impact properties of adhesives are functions of type and content of modifier. In the DCB test, it was observed that while addition of rubber particles increase interfacial fracture energy of epoxy, incorporating SiC particles decrease this parameter. Also, the results...
As-cast mechanical properties of vanadium/niobium microalloyed steels
, Article Materials Science and Engineering A ; Volume 486, Issue 1-2 , 2008 , Pages 1-7 ; 09215093 (ISSN) ; Rassizadehghani, J ; Asgari, S ; Sharif University of Technology
2008
Abstract
Tensile and room temperature Charpy V-notch impact tests along with microstructural studies were used to evaluate the variations in the as-cast mechanical properties of low-carbon steels with and without vanadium and niobium. Tensile test results indicate that good combinations of strength and ductility can be achieved by microalloying additions. While the yield strength and UTS increase up to respectively 370-380 and 540-580 MPa in the microalloyed heats, their total elongation range from 20 to 25%. TEM studies revealed that random and interphase fine-scale microalloy precipitates play a major role in the strengthening of the microalloyed heats. On the other hand, microalloying additions...
Investigation of vacuum annealing effects on physical-mechanical properties of thermoplastic parts
, Article Materials and Design ; Volume 26, Issue 1 , 2005 , Pages 89-93 ; 02613069 (ISSN) ; Mousavi, S ; Sharif University of Technology
Elsevier Ltd
2005
Abstract
Impact and tensile strength of polystyrene and nylon 6 samples, which have been produced by injection molding before and after annealing in different conditions are obtained. Polystyrene samples that are heated on vacuum conditions can deform highly even in temperatures much less than polystyrene glass temperature. This phenomenon is reduced significantly by heating samples to annealing temperature in atmospheric pressure and then removing air from sample environment in constant temperature. Deformation problems for nylon were not so important but due to high temperature implied for annealing of nylon parts, some color change due to oxidative degradation are observed. So for nylon parts a...
Microstructure, fractography, and mechanical properties of hardox 500 steel tig-welded joints by using different filler weld wires
, Article Materials ; Volume 15, Issue 22 , 2022 ; 19961944 (ISSN) ; Haowei, M ; Yarigarravesh, M ; Assari, A. H ; Tayyebi, M ; Tayebi, M ; Hamawandi, B ; Sharif University of Technology
MDPI
2022
Abstract
This paper deals with the effects of three low-carbon steel filler metals consisting of ferritic and austenitic phases on the weld joints of the tungsten inert gas (TIG) welding of Hardox 500 steel. The correlation between the microstructure and mechanical properties of the weld joints was investigated. For this purpose, macro and microstructure were examined, and then microhardness, tensile, impact, and fracture toughness tests were carried out to analyze the mechanical properties of joints. The results of optical microscopy (OM) images showed that the weld zones (WZ) of all three welds were composed of different ferritic morphologies, including allotriomorphic ferrite, Widmanstätten...
Experimental and Theoretical Analysis of Plastic Deformation of Metals under Impact Loading Using Taylor Impact Test
, M.Sc. Thesis Sharif University of Technology ; Naghdabadi, Reza (Supervisor)
Abstract
In most of the engineering applications, the mechanical behavior of materials in high strain rate deformations differs from their behavior in quasi-static deformations. In some engineering problems like impact loading on structures, metal forming and explosive forming, the range of strain rate is about . Taylor impact test is one of the experiments used for characterizing the dynamic behavior of materials in high strain rate deformations. In the Taylor impact test a rigid cylindrical projectile is impacted normally onto a hard and massive surface (anvil), the projectile deforms by mushrooming at the impact end. With plastic wave propagation analysis, the plastic deformation of projectile is...
Geometrical Optimization of Aluminum Alloy Wheels for High Fatigue and Impact Strength
, M.Sc. Thesis Sharif University of Technology ; Khayyat, Ali Akbar (Supervisor) ; Pasharavesh, Abdolreza (Supervisor)
Abstract
After the rise of the automotive industry, aluminum wheels have superseded steel counterparts due to their numerous advantages. Foremost among these benefits is their reduced weight, leading to fuel savings and diminished environmental impact. Moreover, aluminum wheels offer enhanced aesthetics and greater strength in comparison to steel alternatives. This thesis focuses on the geometrical optimization of an aluminum wheel model conforming to the standards set by Iran's Department of Standards, aiming to achieve a higher strength-to-weight ratio. While prior research works have mainly focused on weight reduction while maintaining strength within approved standards, this thesis aims at the...
An energy-based approach for analysis of dynamic plastic deformation of metals
, Article International Journal of Mechanical Sciences ; Volume 66 , January , 2013 , Pages 94-100 ; 00207403 (ISSN) ; Naghdabadi, R ; Arghavani, J ; Sharif University of Technology
2013
Abstract
An energy-based ordinary differential equation is derived for a plastic wave propagating through a Taylor impact test specimen. Using the definition of true strain, an analytical equation is presented to calculate the strain rate across the plastic wave front. Having considered a Johnson-Cook plasticity model for the projectile material, the derived energy equation accompanied by a governing kinematics relation and the strain rate equation is numerically integrated to obtain the final deformed profile of the specimen. The results of the energy based model are then compared with those of the commonly used momentum-based approach as well as the existing experimental data in literature for...
Oblique low-velocity impact on fiber-metal laminates
, Article Applied Composite Materials ; 2016 , Pages 1-13 ; 0929189X (ISSN) ; Mohammadkhani, H ; Bagheri, M. R ; Sharif University of Technology
Springer Netherlands
Abstract
In the present study, oblique low-velocity impact (OLVI) on GLARE fiber-metal laminates (FMLs) has been modeled using finite element analysis (FEA) for the first time. Two types of boundary conditions (BCs) can be considered for impactor in the low-velocity impact: constrained (if the impact angle between the impactor and target remains constant during and after the contact) and free (if rotation of the impactor and change in angle with respect to the target is likely) BCs. The more details of these BCs are described in the paper. The OLVI is numerically modeled for four different impact angles. Effect of BC types and impact angle on energy absorption, as well as maximum contact force, is...
Oblique low-velocity impact on fiber-metal laminates
, Article Applied Composite Materials ; Volume 24, Issue 3 , 2017 , Pages 611-623 ; 0929189X (ISSN) ; Mohammadkhani, H ; Bagheri, M. R ; Sharif University of Technology
Abstract
In the present study, oblique low-velocity impact (OLVI) on GLARE fiber-metal laminates (FMLs) has been modeled using finite element analysis (FEA) for the first time. Two types of boundary conditions (BCs) can be considered for impactor in the low-velocity impact: constrained (if the impact angle between the impactor and target remains constant during and after the contact) and free (if rotation of the impactor and change in angle with respect to the target is likely) BCs. The more details of these BCs are described in the paper. The OLVI is numerically modeled for four different impact angles. Effect of BC types and impact angle on energy absorption, as well as maximum contact force, is...
Effect of thickness and reinforcement configuration on flexural and impact behaviour of GFRP laminates after exposure to elevated temperatures
, Article Composites Part B: Engineering ; Volume 157 , 2019 , Pages 76-99 ; 13598368 (ISSN) ; Ashrafi, H ; Jafari, A ; Zhao, X.-L ; Gholipour, H ; Oskouei, A. V ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
This study investigates the flexural and impact behaviour of GFRP laminates after exposure to elevated temperatures. The effect of fibre's length and orientation, laminate's thickness, and exposure time is studied. A total number of 540 tests in terms of three-point bending and Charpy impact tests were conducted to obtain the mechanical properties. In addition, SEM analyses were carried out to investigate the degradation mechanisms. Finally, statistical study was conducted to investigate the contribution of each variable and develop probabilistic models using ANOVA and linear Bayesian regression method. The results showed that generally the flexural and impact properties of GFRP laminates...
Microstructural and mechanical evaluation of submerged arc welded HSLA 4135 steel by modeled and manufactured granular Cr-Mo bonded active basic flux
, Article Journal of Materials Processing Technology ; Volume 290 , 2021 ; 09240136 (ISSN) ; Mohammadmirzaei, M ; Ebadi, M ; Kokabi, A. H ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Bead-on-plate submerged arc welding was performed on the AISI 4135 heat-treatable low-alloy (HTLA) steel using S2 welding wire and granular Cr-Mo basic flux. The Cr-Mo active flux was produced by the bonded -unfused method. The alloying elements were introduced into the weld metal by active flux. Two methods were introduced for calculating the recovery rate (η) of the alloying elements. Moreover, by defining the slag factor (α) of the process and η of the alloying elements, the amount of a specific element transferred from flux into WM was calculated by the proposed equation. Likewise, microstructure evolutions, inclusions characteristics, longitudinal tensile, indentation, and CVN impact...
Microstructural and mechanical evaluation of submerged arc welded HSLA 4135 steel by modeled and manufactured granular Cr-Mo bonded active basic flux
, Article Journal of Materials Processing Technology ; Volume 290 , 2021 ; 09240136 (ISSN) ; Mohammadmirzaei, M ; Ebadi, M ; Kokabi, A. H ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Bead-on-plate submerged arc welding was performed on the AISI 4135 heat-treatable low-alloy (HTLA) steel using S2 welding wire and granular Cr-Mo basic flux. The Cr-Mo active flux was produced by the bonded -unfused method. The alloying elements were introduced into the weld metal by active flux. Two methods were introduced for calculating the recovery rate (η) of the alloying elements. Moreover, by defining the slag factor (α) of the process and η of the alloying elements, the amount of a specific element transferred from flux into WM was calculated by the proposed equation. Likewise, microstructure evolutions, inclusions characteristics, longitudinal tensile, indentation, and CVN impact...
Investigating the effect of rolling strain on fracture behavior of roll bonded Al6061 laminates under quasi-static and dynamic loading
, Article Materials Science and Engineering A ; Volume 558 , 2012 , Pages 82-89 ; 09215093 (ISSN) ; Bagheri, R ; Seyed Reihani, S. M ; Sharif University of Technology
2012
Abstract
Damage tolerance improvement has been reported by laminating aluminum alloys and composites by researchers. Three-layer laminates comprising Al6061 outer layers and Al1050 interlayer have been roll bonded in this research. While most of the works done have focused on fracture properties of roll bonded Al laminates in crack arrester geometry, this study explores their behavior in crack divider configuration. Rolling strain is varied to control the interfacial bonding in laminates. The fracture behavior of laminates and the constituent material was examined via three-point bending and impact tests. This study presents significant improvement in damage tolerance of laminates compared to their...
An investigation into welding of 304 stainless steel to a medium carbon steel
, Article Welding in the World ; Volume 53, Issue SPECIAL ISSUE , 2009 , Pages 575-580 ; 00432288 (ISSN) ; Nasiri, A. M ; Kokabi, A. H ; Serajzadeh, S ; Sharif University of Technology
Abstract
In this work, fusion welding of CK45 carbon steel and 304 stainless steel was performed using GTAW technique. Both ER308-L and ERNi-1 filler metals with and without buttering conditions were employed. Then, the welded samples were studied utilizing optical metallography, scanning electron microscopy, microhardness, polarization and impact tests. It is observed that in the buttered specimens with nickel wire, the structure of weld metal was completely austenitic while the microstructure of unbuttered one was austenitic-ferritic and also, a carburized region in the weld metal next to the fusion line were observed. Microstructures and microhardness variation in the weld metal after socking at...
Failure analysis of bolt connections in fired heater of a petrochemical unit
, Article Engineering Failure Analysis ; Volume 92 , 2018 , Pages 327-342 ; 13506307 (ISSN) ; Chamani, M ; Reza Kashyzadeh, K ; Mostafazade, A ; Mahmoudi, A. H ; Afshin, H ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
The main function of a fired heater in a petrochemical site is to produce supersaturated steam. Due to extremely difficult working conditions and high temperatures, there is a very high probability of failures in different parts of a fired heater. In the fired heater under study, tube guides are frequently damaged due to malfunctions and fractures in bolt connections. To investigate the nature of such fractures, Computational Fluid Dynamics (CFD), Finite Element (FE) method, Charpy impact test and fractography were used. To obtain the temperature of various components of the fired heater, a CFD analysis was carried out by considering the combustion process and modeling the central and side...
Damage behavior of fiber reinforced composite plates subjected to drop weight impacts
, Article Composites Science and Technology ; Volume 66, Issue 1 , 2006 , Pages 61-68 ; 02663538 (ISSN) ; Shokrieh, M. M ; Lessard, L ; Sharif University of Technology
2006
Abstract
Fiber reinforced materials are widely used in many industrial structures including automotive, aviation, and civil due to their lower weights compared to metal structures. Full-composite body structures, especially in automotive and aviation applications, are becoming a proper replacement for current metal ones. For this reason, damage of such structures subjected to impact is a crucial case study in current research. The typical types of damages are mainly caused during production, repair, maintenance, or by particle crashes during function, and collisions between different structures. In this paper, four different fiber reinforced composite plates are studied after being impacted by a...
Microstructural and mechanical evaluations of SAW by manufactured granular basic bonded Cr, Mo, and Cr–Mo active fluxes on ST37 low carbon steel
, Article International Journal of Advanced Manufacturing Technology ; Volume 119, Issue 9-10 , 2022 , Pages 6335-6347 ; 02683768 (ISSN) ; Mohammadmirzaei, M ; Ebadi, M ; Kokabi, A. H ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Abstract: Bead-on-plate submerged arc welding was conducted on St37 steel by manufactured Cr, Mo, and Cr–Mo active basic fluxes produced via the unfused bonded method. The base metal heat-affected zone and weld metal (WM) microstructures were identified and characterized by optical microscopy and scanning electron microscopy. Furthermore, each element’s recovery rate (η) and slag factor (α) determine the amount of element transferred from flux into WM. Then, the ferrite morphologies volume fraction of WMs was measured. Moreover, the chemical analysis of slag and inclusions was evaluated by point scan energy-dispersive X-ray spectroscopy and extensively discussed. The number density and...
Influence of four wires tandem submerged arc welding process on heat affected zone properties in high strength pipeline steel
, Article Proceedings of the 2010 International Conference on Mechanical, Industrial, and Manufacturing Technologies, MIMT 2010, 22 January 2010 through 24 January 2010 ; 2010 , Pages 85-89 ; 9780791859544 (ISBN) ; Kokabi, A. H ; Madaah Hosseini, H. R ; Shang, C. J ; Hui, G ; Wei, L. Z ; Sharif University of Technology
2010
Abstract
The objective of this investigation was to provide a detailed evaluation of the heat affected zone properties of a high-strength pipeline steel. The X80 high-strength low-alloy microalloyed steel was supplied as a hot rolled plate with accelerated cooling. The four-wire tandem submerged arc welding process with different heat input was used to generate welded joints. The microstructure of the heat affected zone depended on heat input values. M/A constituent appeared in the microstructure of HAZ region for all of the specimens along the prior-austenite grain boundaries and between bainitic ferrite laths. Charpy impact specimens were notched in four locations: FL (fusion line), FL+1mm, FL+2mm...
Investigation of in situ prepared polypropylene/clay nanocomposites properties and comparing to melt blending method
, Article Materials and Design ; Volume 31, Issue 1 , 2010 , Pages 76-84 ; 02641275 (ISSN) ; Ramazani S. A. A ; Javan Nikkhah, S ; Sharif University of Technology
Abstract
The morphological, physical and mechanical properties of polypropylene/clay nanocomposites (PPCNs) were prepared by in situ polymerization are investigated. Non-modified scmectite type clay (e.g. bentonite) was used to prepare bi-supported Ziegler-Natta catalyst of TiCl4/Mg(OEt)2/clay. Exfoliated PPCNs were obtained by in situ intercalative polymerization of propylene using produced bi-supported catalyst. X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM) micrograph were used to assess the clay morphology and dispersion of clay. The crystalline structures of PPCNs were characterized by differential scanning calorimetry (DSC). The mechanical properties of PPCNs were...
Role of tandem submerged arc welding thermal cycles on properties of the heat affected zone in X80 microalloyed pipe line steel
, Article Journal of Materials Processing Technology ; Volume 211, Issue 3 , 2011 , Pages 368-375 ; 09240136 (ISSN) ; Kokabi, A. H ; Hosseini, H. R. M ; Sharif University of Technology
Abstract
The influence of thermal cycles on the properties of the coarse grained heat affected zone in X80 microalloyed steel has been investigated. The thermal simulated involved heating the X80 steel specimens to the peak temperature of 1400 °C, with different cooling rates. The four-wire tandem submerged arc welding process, with different heat input values, was used to generate a welded microstructure. The martensite/austenite constituent appeared in the microstructure of the heat affected zone region for all the specimens along the prior-austenite grain boundaries and between the bainitic ferrite laths. The blocky-like and stringer martensite/austenite morphology were observed in the heat...