Search for: tensile-testing
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    Determination of tearing energy from uniaxial tension tests of aluminum alloy sheet

    , Article Journal of Materials Processing Technology ; Volume 147, Issue 2 , 2004 , Pages 185-190 ; 09240136 (ISSN) Mahmudi, R ; Mohammadi, R ; Sepehrband, P ; Sharif University of Technology
    Tearing energy of AA5010 aluminum alloy sheets has been studied by the single tensile testing (STT) and multiple tensile testing (MTT) methods. The total energy required to tear the specimens was assumed to be composed of two components; one associated with uniform plastic deformation, which occurs in the work-hardening range of the material, and the other with post-uniform deformation and tearing which leads to the failure of the specimens. In the STT method, tearing energy was calculated by subtracting the plastic deformation energy, dissipated in the uniform deformation range, from the total energy absorbed by a single specimen during tension. In the MTT method, which uses different... 

    Tearing energy of an annealed bilayer sheet through multiple and single tensile tests

    , Article Materials Science and Engineering A ; Volume 528, Issue 29-30 , November , 2011 , Pages 8800-8803 ; 09215093 (ISSN) Beygi, R ; Kazeminezhad, M ; Sharif University of Technology
    Tearing energies of annealed Al-steel bilayer sheets are investigated through multiple and single tensile tests. Total tearing energy of two layers determined separately by single tensile test is equal to tearing energy of bilayer sheet. It means that the bond between two layers has no effect on tearing energy  

    Simulated and experimental investigation of stretch sheet forming of commercial AA1200 aluminum alloy

    , Article Transactions of Nonferrous Metals Society of China (English Edition) ; Vol. 24, issue. 2 , February , 2014 , pp. 484-490 Esmaeilizadeh, R ; Khalili, K ; Mohammadsadeghi, B ; Arabi, H ; Sharif University of Technology
    The simulation and experimental results obtained from stretching test of a commercial sheet of AA1200 aluminum alloy were compared and evaluated. Uniaxial tensile tests were carried out to obtain the required input parameters for simulation. Finite element analysis of the forming process was carried out using Abaqus/Explicit by considering von Mises and Hill-1948 yield criteria. Simulation results including punch force and strain distribution were compared and validated with the experimental results. The results reveal that using anisotropic yield criteria for simulation has a better match in both cases with the experiments  

    Flow behavior and mechanical properties of a high silicon steel associated with dynamic strain aging

    , Article Journal of Materials Engineering and Performance ; Volume 21, Issue 9 , September , 2012 , Pages 1919-1923 ; 10599495 (ISSN) Akhgar, J. M ; Serajzadeh, S ; Sharif University of Technology
    Springer  2012
    Flow behavior of two grades of steel including a high silicon (HS) steel and a plain low carbon steel as the reference were considered in this work. Tensile testing at temperatures varying between 25 and 550 °C and different strain rates in the range of 4×10-5 to 0.1 s-1 were conducted and the mechanical properties, such as elongation at fracture point and strain rate sensitivity were then determined. It is observed that for both steels, dynamic strain aging occurs in the employed deformation conditions, however, the region of serrated flow and the type of the serration were somehow different. For the case of the HS steel, the serrated flow region is shifted to the higher temperatures and... 

    The effect of remelting on the melt and casting quality in Al-7%Si-Mg castings

    , Article Materials Science and Engineering A ; Vol. 605 , 2014 , Pages 203-209 ; ISSN: 09215093 Eisaabadi, B. G ; Tiryakioglu, M ; Davami, P ; Kim, S. K ; Yoon, Y. O ; Yeom, G. Y ; Kim, N. S ; Sharif University of Technology
    An experiment was conducted to determine whether allowing an aluminum melt to solidify in the crucible and later remelting it would improve the quality of the melt and the casting. To investigate this, data were collected through reduced pressure test, density measurement, metallography, X-ray radiography and tensile testing and analyzed statistically. Results indicated that remelting improved the quality of the melt by reduction of the number of defects in the casting and their area and volume fractions. The improvement in elongation of remelted specimens was found to be statistically significant. Analysis of deformation characteristics showed that the improvement in elongation is due to... 

    Comparison of the mechanical properties of NiTi/Cu bilayer by nanoindentation and tensile test: Molecular dynamics simulation

    , Article Materials Research Express ; Volume 3, Issue 12 , 2016 ; 20531591 (ISSN) Fazeli, S ; Vahedpour, M ; Sadrnezhaad, S. K ; Sharif University of Technology
    Institute of Physics Publishing  2016
    Molecular dynamics simulation was used to study of mechanical properties of NiTi/Cu bilayer by nanoindentation and tensile testing. A comparison has been made among mechanical properties measured and plastic deformation process at different copper thickness during nanoindnetation and tensile test of the samples. Embedded atom method potentials for describing of inter-Atomic interaction and Nose-Hoover thermostat and barostat are employed in the simulation at 400 K. The results showed that as the copper film thickness decreased, the maximum load and hardness values increased during nanoindetation. Saha and Nix model is used to describe reduced young's modulus behaviour of the bilayer system... 

    Effect of weld nugget size on overload failure mode of resistance spot welds

    , Article Science and Technology of Welding and Joining ; Volume 12, Issue 3 , 2007 , Pages 217-225 ; 13621718 (ISSN) Pouranvari, M ; Asgari, H. R ; Mosavizadch, S. M ; Hoveida Marashi, P ; Goodarzi, M ; Sharif University of Technology
    In the present paper, effects of welding current, welding time, electrode pressure and holding time on the weld nugget size were studied. A failure mechanism was proposed to describe both interfacial and pullout failure modes. This mechanism was confirmed by SEM investigations. In the light of this mechanism, the effect of welding parameters on static weld strength and failure mode was studied. Then, an analytical model was proposed to predict failure mode and to estimate minimum nugget diameter (critical diameter) to ensure pullout failure mode in shear tensile test. On the contrary to existing industrial standards, in this model, critical nugget diameter is attributed to metallurgical... 

    Chemo-physical properties of renal capsules under ultraviolet-c exposure

    , Article Journal of Applied Physics ; Vol. 116, Issue. 5 , 2014 ; ISSN: 00218979 Baghapour, Sh ; Parvin, P ; Reyhani, A ; Mortazavi, S. Z ; Mokhtari, S ; Amjadi, A ; Sharif University of Technology
    The renal capsule tissue of lamb was irradiated with ultraviolet-C light and the treated samples were analyzed by uniaxial tensile test, dynamic mechanical analysis, attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and contact angle measurements. It was shown that the skin cross-linking is dominant in low doses in accordance with the contact angle assessment. Conversely, the strong bulk degradation takes place at high doses. Similarly, the bulk cross-linking affects the mechanical tests as to enhance the stiffness at low doses, whereas strong degradation occurs at high doses that mainly arises from the strong bulk chain scission  

    Evaluation of dissimilar welds of 5083-H12 and 6061-T6 produced by friction stir welding

    , Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Volume 44, Issue 8 , 2013 , Pages 3697-3707 ; 10735623 (ISSN) Ghaffarpour, M ; Kolahgar, S ; Dariani, B. M ; Dehghani, K ; Sharif University of Technology
    In the present study, the dissimilar aluminum alloys of 5083-H12 and 6061-T6 were joined by friction stir welding (FSW). Then, the design of experiments (DOE), the Box-Benken method, and the response surface methodology (RSM) were used to optimize the effective parameters of the FSW process. The optimized parameters that led to the maximum tensile strength in dissimilar friction stir welded sheets were determined. The predicted results were then compared with those measured experimentally. The results show that there is good agreement between the predicted and measured amounts. By applying the limit dome height (LDH) test, the formability of friction stir welded sheets was studied. During... 

    A new polypropylene/clay nanocomposite for replacement of engineering plastics in automotive application

    , Article Annual Technical Conference - ANTEC, Conference Proceedings ; Volume 1 , 2012 , Pages 102-109 ; 9781622760831 (ISBN) Zokaei, S ; Motamedi, P ; Bagheri, R ; Sharif University of Technology
    SPE  2012
    Polypropylene matrix nanocomposites reinforced with organoclay are investigated and their ability to replace some polyamide automotive parts is evaluated. This is so interesting from industrial point of view because of cost saving and ease of processing and recycling. This work is focused on different nanocomposite systems which are PP/nanoclay, and PP/PA/nanoclay. Also the effect of compatibilizer is presented here. Structure of these systems are studied by using WAXD, TEM and SEM. Mechanical properties of specimens are studied using uniaxial tensile test. As it will be demonstrated, nanoclay sheets tend to disperse in PA particles. On the other hand, introducing nanoclay into PP/PA blends... 

    Investigation on friction stir lap welding of aluminium to aluminium clad steel sheets

    , Article Science and Technology of Welding and Joining ; Volume 17, Issue 3 , 2012 , Pages 231-236 ; 13621718 (ISSN) Movahedi, M ; Kokabi, A. H ; Seyed Reihani, S. M ; Sharif University of Technology
    In this work, the feasibility of friction stir lap welding an aluminium alloy (Al-5083) to the aluminium clad steel sheet was studied. The welded joints were characterised by various methods including shear-tensile test and optical microscopy and scanning electron microscopy. The results indicated that sound and defect free joints were obtained. The fracture loads of the samples reached up to 94% compared with that of the steel base metal. Moreover, the joint strength linearly increased with the decrease in thickness of the aluminium layer roll bonded on the steel sheet. It was also shown that welding rotation and travel speed variation did not considerably impact the fracture loads in the... 

    Hot ductility of a Fe-Ni-Co alloy in cast and wrought conditions

    , Article Materials and Design ; Volume 32, Issue 5 , 2011 , Pages 2956-2962 ; 02641275 (ISSN) Yazdani, M ; Abbasi, S. M ; Momeni, A ; Karimi Taheri, A ; Sharif University of Technology
    The hot ductility of Fe-29Ni-17Co alloy was studied in both cast and wrought conditions by hot tensile tests over temperature range of 900-1250°C and at strain rates of 0.001-1s-1. Over the studied temperature range, the wrought alloy represented higher elongation and reduction in area as compared to the cast alloy. Dynamic recrystallization was found responsible for the higher hot ductility of the wrought alloy and the improvement of hot ductility of the cast alloy at high temperatures. At temperature range of 1000-1150°C the wrought alloy exhibited a hot ductility drop while a similar trough was not observed in case of the cast alloy. It was also found that at temperatures of 1150-1250°C... 

    Investigation into dynamic strain aging behaviour in high carbon steel

    , Article Ironmaking and Steelmaking ; Volume 37, Issue 2 , Jul , 2010 , Pages 155-160 ; 03019233 (ISSN) Kohandehghan, A. R ; Sadeghi, A. R ; Akhgar, J. M ; Serajzadeh, S ; Sharif University of Technology
    In this work, the phenomenon of dynamic strain aging in a high carbon steel is studied and different initial microstructures including fine and coarse pearlite structures are considered. Tensile tests at different temperatures and strain rates are performed to evaluate the occurrence of dynamic strain aging and mechanical properties as well as to calculate apparent activation energies for onset and termination of dynamic strain aging. The results show that dynamic strain aging occurs for both microstructures while the initial microstructures alters the activation energies for appearance and termination of this phenomenon. The microstructural studies illustrate that a combination of cementite... 

    Computer Simulation of Coiled Carbon Nanotubes Deformation By Molecular Dynamics Approach

    , M.Sc. Thesis Sharif University of Technology Shahini, Ehsan (Author) ; Karimi Taheri, Ali (Supervisor)
    A Coiled Carbon Nanotube (CCNT) can be geometrically viewed as a graphene sheet whose rolled and twisted to form a helically coiled nanotube. It is the strongest material ever measured with strengthexceeding more than hundred times of steel.The strength of a CCNT iscritically influenced by temperature, tube diameter, strain rate and pitch angle. In this study,a Molecular Dynamics (MD) simulationis performed to understand the effect of temperature, strain rate, tube diameter and pitch angle on the mechanical properties of CCNTs. Results indicate thatexisting the stone-wales defects is necessaryfor thermodynamic stability of CCNTs.According to the stress-strain curves it was observed thatyield... 

    Dynamic model of a flying manipulator with two highly flexible links

    , Article Applied Mathematical Modelling ; Volume 32, Issue 10 , 2008 , Pages 2117-2132 ; 0307904X (ISSN) Zohoor, H ; Khorsandijou, S. M ; Sharif University of Technology
    Nonlinear dynamic model of a flying manipulator with two revolute joints and two highly flexible links is obtained using Hamilton's principle. Flying base of the manipulator is a rigid body. Stress is treated three dimensionally in the isotropic linearly-elastic links, but the in-plane and out-of-plane warpings of the links' cross-sections are neglected. Although the links' cross-sections undergo negligible elastic orientation, their models are more accurate than a nonlinear 3D Euler-Bernoulli beam. Tension, compression, twisting and spatial deflections of each link are coupled to each other by some nonlinear terms including two new ones. In the issue of flying flexible-link manipulators new... 

    High temperature mechanical properties of triple phase steels

    , Article Materials Letters ; Volume 61, Issue 4-5 , 2007 , Pages 1023-1026 ; 0167577X (ISSN) Akbarpour, M. R ; Sharif University of Technology
    A 0.15% C-1.2% Si-1.7% Mn steel was intercritically annealed at 780 °C for 5 min and then isothermally held at 400 °C for 4 min followed by oil quenching to room temperature and the annealed microstructure consist of 75% ferrite, 15% bainite and 10% retained austenite was produced. Samples of this steel with triple phase structure were tensile tested at temperature range of 25-450 °C. Stress-strain curves showed serration flow at temperature range of 120-400 °C and smooth flow at the other temperatures. All of the stress-strain curves showed discontinuous yielding at all testing temperatures. Both yield and ultimate tensile strength decreased with increasing temperature, but there exists a... 

    Comparison of the experimental behavior of a shape memory alloy in compression and tension

    , Article 2003 ASME International Mechanical Engineering Congress, Washington, DC., 15 November 2003 through 21 November 2003 ; Volume 68 , 2003 , Pages 471-478 ; 07334230 (ISSN) Hesse, T ; Ghorashi, M ; Inman, D. J ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2003
    The concept of Shape Memory Alloy (SMA) has been a subject of extensive research in the recent few years. In many SMA applications, wire elements have been used in order to control structural specifications like shape and stiffness. Since a wire can only be subjected to tensile forces, the available theoretical models for SMA discuss only the tensile loading. The present paper is an endeavor to overcome this shortcoming. It gives experimental results for tension and compression tests on specimens (having different geometries) made of an identical shape memory alloy. The corresponding results are compared with each other. Using stress-strain diagrams, several important material properties are... 

    Molecular Dynamics Simulation of Mechanical Behavior of Metalic Nanostructures

    , M.Sc. Thesis Sharif University of Technology Rabiefar, Hossein (Author) ; Simchi, Abdolreza (Supervisor) ; Kazeminezhad, Mohsen (Supervisor)
    In this work, mechanical behavior of Ni nanowires with various dimensions under tensile loading at different temperatures and strain rates was simulated by molecular dynamics. Lennard-Jones and Sutton-Chen potential functions were utilized. The relationship between the tensile properties of Ni nanowires and temperature, strain rate, aspect ratio and crystal orientation was studied. It was shown that with increasing the aspect ratio of the nanowires the strength of the material decreases. A change in the fracture mode of the nanowire from slippage at low strain rates (<10 m/s) to amorphous deformation at high loading rates was observed. The crystal orientation was found to influence the... 

    Investigating the Effect of Various Additives on the Curing Time of Chip Seal and Chip Seal Treatments in Different Climate Conditions.

    , M.Sc. Thesis Sharif University of Technology Sadeghi, Amir (Author) ; Motamed, Arash (Supervisor)
    Recently, a new method to investigate chip seal performance has developed by a research team at Sharif University of Technology. This study investigates the effect of various additives such as CRM, SBR Latex, Hydrated Lime and Ordinary Portland Cement (OPC), on the curing time of chip seal by this method. In addition, the chip seal treatments were investigated in different climate conditions like Wet and Wet-Freeze zones. The overall performance of mixture specimens evaluated using creep loading test. In fact, the bonding properties between aggregates and surface of Hot Mix Asphalt measured. The test results were analyzed by using of the work and time parameters. These parameters were... 

    Investigating the Tensile Behaviour of a Type of Fibre-Reinforced Concrete

    , M.Sc. Thesis Sharif University of Technology Irandoust, Mohammad (Author) ; Khonsari, Vahid (Supervisor)
    Low tensile strength and also low strain capacity make plain concrete a ‘brittle’ material. To overcome this shortcoming, the addition of fibre as a reinforcing material has proved to be a reasonable solution. One of the crucial factors in deciding to make this type of concrete is the cost of fibre, which varies depending on its type. In this project a special type of fibre which does not cost a lot and at the same time has a high strength has been used. To investigate the effect of the fibre on the tensile strength of concrete, splitting tensile test (Brazilian test) was adopted. Altogether, 30 standard cylindrical specimens with dimensions of 15 × 30 cm2 were made (3 of each type) which...