2017
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Linear Numerical Stress Analysis of Concrete Specimens under Different Direct Tension Test Setups
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Tensile strength is one of the basic and important mechanical properties of concrete. The measurement of the tensile strength of concrete is not easy. This is because this property of concrete is dependent on the different test setups that must be used. Indirect methods have been used hitherto to measure tensile strength of concrete. These methods though widely accepted, do not provide the true tensile strength of concrete in comparison with direct methods. According to this, the present study focuses on the analytical and experimental investigation of the prismatic concrete specimensunder direct tension test setups. In this paper, different test setups were studied to produce a more uniform tensile stress distribution and minimize stress concentration at both ends of the concrete specimens with normal compressive strength. ABAQUS software was employed to carry out the finite element analysis of the concrete specimens under direct tension test setups.
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12


H.
Dabbagh
Civil Engineering Department, Kurdistan University, Sanandaj, Iran.
Civil Engineering Department, Kurdistan University
Iran
h.dabbagh@uok.ac.ir


A.
Nosoudi
Civil Engineering Department, Kurdistan University, Sanandaj, Iran.
Civil Engineering Department, Kurdistan University
Iran
arina.nosoodi@eng.uok.ac.ir


H.
Mohammad Doost
Civil Engineering Department, Kurdistan University, Sanandaj, Iran.
Civil Engineering Department, Kurdistan University
Iran
hooman.5058@gmail.com
Direct tension
tensile strength
Tensile stress distribution
Finite element analysis
ABAQUS
[[1] J.M. Raphael, Tensile strength of concrete, Aci. J., 81(2) (1984) 158165.##[2] M.P. Luong, Tensile and shear strengths of concrete and rock, Eng. Fract. Mech., 35(13) (1990) 127135.##[3] C. Rocco, G.V. Guinea, J. Planas, M. Elices, Review of the splittingtest standards from a fracture mechanics point of view, Cement. Concrete. Res., 31(1) (2001) 7382.##[4] H. Schuler, C. Mayrhofer, K. Thoma, Spall experiments for the measurement of the tensile strength and fracture energy of concrete at high strain rates, Int. J. Impact. Eng., 32(10) (2006) 16351650.##[5] D. Yan, G. Lin, Dynamic properties of concrete in direct tension, Cement. Concrete. Res., 36(7) (2006) 13711378.##[6] R.S. Olivito, F.A. Zuccarello, An experimental study on the tensile strength of steel fiber reinforced concrete. Compos. Part. BEng., 41(3) (2010) 246255.##[7] Y. Tian, S. Shi, K. Jia, S. Hu, Mechanical and dynamic properties of high strength concrete modified with lightweight aggregates presaturated polymer emulsion. Const. Build. Mater., 93 (2015) 11511156.##[8] M.W. Ibrahim, A.F. Hamzah, N. Jamaluddin, P.J. Ramadhansyah, A.M. Fadzil, Split tensile strength on selfcompacting concrete containing coal bottom ash. Proc. Soc. Behv., 195 (2015) 22802289.##[9] R.V. Silva, J. DeBrito, R.K. Dhir, Tensile strength behaviour of recycled aggregate concrete. Const. Build. Mater., 83 (2015) 108118.##[10] N.N. Gerges, C.A. Issa, S. Fawaz, Effect of construction joints on the splitting tensile strength of concrete. Case Studies in Construction Materials, 3 (2015) 8391.##[11] ASTM, Standard test method for flexural strength of concrete (using simple beam with thirdpoint loading), Am. Soc. Test. Mater. C., (2002) 78102.##[12] ASTM, Standard test method for flexural strength of concrete (Using sample beam with centerpoint loading), Annual book of ASTM standards, Am. Soc. Test. Mater. C., (2003) 293302.##[13] ASTM, Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens, C. (2004) 496/C 496M04.##[14] C. Rocco, G.V. Guinea, J. Planas, M. Elices, Size effect and boundary conditions in the Brazilian test: experimental verification. Mater. Struct., 32(3) (1999) 210217.##[15] C. Rocco, G.V. Guinea, J. Planas, M. Elices, Size effect and boundary conditions in the Brazilian test: theoretical analysis. Mater. Struct., 32(6) (1999) 437444.##[16] W. Zheng, A.KH. Kwan, P.K.K. Lee, Direct tension test of concrete, Materials, 98(1) (2001) 6371.##[17] V. Kadlecek, Z. Spetla, Direct tensile strength of concrete, Materials, 2(4) (1967) 749767.##[18] F. Min, Z. Yao, T. Jiang, Experimental and Numerical Study on Tensile Strength of Concrete under Different Strain Rates. Scientific. World. J., 2014 (2014) 11 173531.##[19] S. Swaddiwudhipong, H.R. Lu, T.H. Wee, Direct tension test and tensile strain capacity of concrete at early age. Cement. Concrete. Res., 33(12) (2003) 20772084.##[20] F. Alhussainy, H.A. Hasan, S. Rogic, M.N. Sheikh, M.N. Hadi, Direct tensile testing of selfcompacting concrete, Const. Build. Mater., 112 (2016) 903906.##[21] H. Wu, Q. Zhang, F. Huang, Q. Jin, Experimental and numerical investigation on the dynamic tensile strength of concrete, Int. J. Impact. Eng., 32(1) (2005) 605617.##[22] Y.B. Lu, Q.M. Li, About the dynamic uniaxial tensile strength of concretelike materials, Int. J. Impact. Eng., 38(4) (2011) 171180.##[23] A. Fahimifar, M. Malekpour, Experimental and numerical analysis of indirect and direct tensile strength using fracture mechanics concepts, B. Eng. Geol. Environ., 71(2) (2012) 269283.##[24] H.F. Gonnerman, E.C. Shuman, Compression, flexure and tension tests of plain concrete, Aci. J., 28(2) (1928) 527564.##[25] M. Saito, Direct tensile fatigue of concrete by the use of friction grips, Aci. J., 80(5) (1983) 431438.##[26] V.S. Gopalaratnam, S.P. Shah, Softening response of plain concrete in direct tension, Aci. J., 82(3) (1985) 310323.##[27] X. Nianxiang, L. Wenyan, Determining tensile properties of mass concrete by direct tensile test, Materials, 86(3) (1989) 214219.##[28] D.V. Phillips, Z. Binsheng, Direct tension tests on notched and unnotched plain concrete specimens. Mag. Concrete. Res., 45(162) (1993) 2535.##[29] RILEM TC, Direct Tension of Concrete Specimens 1975 TC14CPC, RILEM Technical Recommendations for the Testing and Use of Construction Materials, (1994) 2324.##[30] U.S. Bureau of Reclamation, Procedure for Direct Tensile Strength, Static Modulus of Elasticity, and Poissons Ratio of Cylindrical Concrete Specimens in Tension (USBR 491492) Concrete Manual, Part 2, 9th Edition, U.S. Bureau of Reclamation, Denver, (1992) 726731.##[31] ABAQUS Analysis Users Manual, Version 6.142, (2014) Dassault Systemes Simulia Corp. RI, USA.##]
A New Method for Correcting the StressStrain Curves after Bulging in Metals
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True stressstrain curve has a basic role in the analysis of deformation in theoretical plasticity and numerical simulations. Because of the triaxial state of stresses in the necking or bulging zones, in tension and the compression tests respectively, the true stressstrain curves obtained from relationsare no longer valid and must be corrected. Various correction techniques have been proposed and can be found in literatures. In this study, a new semianalytical approach for correction of the stressstrain curve in compression test for circular crosssection specimens was introduced and a relation for the correction factor was derived based on the theory of plasticity. This relation requires only a few experimental surface strain measurements which can easily be done using an image processing technique. The correction factor formula was obtained in terms of the initial radius of specimen, the bulge radius, and the surface strain on the bulge surface. The proposed approach in this study was compared with the results of the numerical simulations. Simulation was used to correct the stressstrain curve based on the optimization method with comparing the bulging profile of tested samples and ones simulated by using genetic algorithm.
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F.
Fariba
Mechanical Engineering Department, Hamedan Branch, Islamic Azad University, Hamedan, Iran.
Mechanical Engineering Department, Hamedan
Iran
farzad.fariba@gmail.com


M.
Ahmadpour
Mechanical Engineering Department, Hamedan Branch, Islamic Azad University, Hamedan, Iran.
Mechanical Engineering Department, Hamedan
Iran
a.ahmadpur@gmail.com


H.
Bahrami
Department of Computer Science, South Tehran Branch, Islamic Azad University, Tehran, Iran.
Department of Computer Science, South Tehran
Iran
hadi.bahrami@gmail.com
Stressstrain curve
Correction factor
Image processing method
Numerical simulation
[[1] G.H. Majzoobi, F. Fariba, M.K. Pipelzadeh, S. Hardy, A new approach for the correction of the stressstrain curves after necking in metals, J. Strain. Analysis., 13 (2014) 253266.##[2] F. Barati, S. Kazemi, Modeling flow stress compressive curves of AZ71 Magnesium alloy at high temperature and various strain rates, J. Science and Today World., 3 (2014) 7274.##[3] P.W. Bridgeman, The stress distribution at the neck of a tension specimen, Trans. Amer. Soc. Metal, 32 (1944) 553574.##[4] E. Siebel, A. Pomp, Determination of flow stress and friction with the upsetting test. Mitt. KWI, 9 (1927) 157171.##[5] Kocaker, B, Production properties prediction after forming process sequence, MSc Thesis. Turkey: Middle East Technical University; 2003.##[6] Y. Sato, Y. Takeyama, An extrapolation method for obtaining stressstrain curves at high rates of strain in uniaxial compression, Tech. Rep. Tohoku. Univ., 44 (1980), 287302.##[7] E. Parteder, R. B¨unten, Determintion of flow curve by means of a compression test under sticking friction condition using an iterative finite element procedure, J. Mater. Process. Tech., 74 (1998) 227223.##[8] G.H. Majzoobi, F. Fres, Determination of material parameter under dynamic loading part I: Experiments and simulation, J. Comp. Mater., 49 (2010) 192200.##[9] G.H. Majzoobi, R. Bagheri, J. PayandehPeyman, Determination of material parameter under dynamic loading part II, Optimization, J. Comp. Mater. Sci., 49 (2010) 201208.##[10] O. Etttouny, D. Ehardt, A method for inprocess failure prediction in cold upset firging, J of engineering and industrial, 105 (1983) 161167.##[11] ASTM, E8. Standard methods of tension testing of metallic materials, Annual book of ASTM standard. American society for testing and materials. 3.01.##]
Evaluation Effects of Modeling Parameters on the Temperature Fields and Residual Stresses of ButtWelded Stainless Steel Pipes
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In this paper, the effects of modeling parameters on the temperature field and residual stresses of buttwelded stainless steel pipes were investigated by using finite element modeling in ABAQUS code. The investigated parameters included, heat flux distribution, latent heat, and heat flux type. The birth and death techniques were utilized to consider mass addition from Y308L filler metal into the weld pool. The moving heat source and convection heat transfer were also modeled by a user subroutine DFLUX and FILM in ABAQUS code. In this work, for verification of FE modeling the temperature fields and residual stresses were compared with available experimental results. The simulation results showed that heat flux with a double ellipsoidal distribution proposed by Goldak associated with latent heat parameter and employed a fully volumetric arc heat input, representing the best match with the experimental data.
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S.
Feli
Mechanical Engineering Department, Razi University, Kermanshah, Iran.
Mechanical Engineering Department, Razi University
Iran
felisaeid@gmail.com


M.E.
Aalami Aaleagha
Mechanical Engineering Department, Razi University, Kermanshah, Iran.
Mechanical Engineering Department, Razi University
Iran
me_aalami_aleagha@yahoo.com


M.R.
Jahanban
Mechanical Engineering Department, Razi University, Kermanshah, Iran.
Mechanical Engineering Department, Razi University
Iran
mohammadreza.jahanban@yahoo.com
Residual stress
Buttwelded
Stainless steel pipe
Temperature field
[[1] D. Deng, H. Murakawa, Numerical simulation of temperature field and residual stress in multipass welds in stainless steel pipe and comparison with experimental measurements, Comp. Mater. Sci., 37(3) (2006) 269277.##[2] B. Brickstad, B.L. Josefson, A parametric study of residual stresses in multipass buttwelded stainless steel pipes, Int. J. Pres. Ves. Pip., 75(1) (1998) 1125.##[3] T. TsoLiang, C. PengHsiang, T. WenCheng, Effect of welding sequences on residual stresses, Comput. Struct., 81 (2003) 273286.##[4] C.H. Lee, K.H. Chang, Threedimensional finite element simulation of residual stresses in circumferential welds of steel pipe including pipe diameter effects, Mat. Sci. Eng., A 487 (2008) 210218.##[5] I. SattariFar, M.R. Farahani, Effect of the weld groove shape and pass number on residual stresses in buttwelded pipes, Int. J. Pres. Ves. Pip., 86 (2009) 723731.##[6] S. Feli, M. E. Aalami Aleagha, M. Foroutan, E. Borzabadi Farahani, Finite element simulation of welding sequences effect on residual stresses in multipass buttwelded stainless steel pipes, J. Press. Vessel. Technol., 134(1) (2012) 9 011209.##[7] M. Foroutan, M. E. AalamiAleagha, S. Feli, S. Nikabadi, Investigation of hydrostatic pressure effect on the residual stresses of circumferentially buttwelded steel pipes, J. Press. Vessel. Technol., 134(3) (2012) 4 034503.##[8] Dean Deng, FEM prediction of welding residual stress and distortion in carbon steel considering phase transformation effects, Mater. Des., 30 (2009) 359366.##[9] A. Goldak John, M. Akhlaghi, Computational Welding Mechanics, Springer Science, 2005.##[10] V. Pavelic, R. Tanbakuchi, O.A. Uyehara, P. S. Myers, Experimental and computed temperature histories in Gas Tungsten Arc Welding of thin plates, Weld. J., 48(7) (1969) 295305.##]
An Analytical Model for Long Tube Hydroforming in a Square CrossSection Die Considering Anisotropic Effects of the Material
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In this paper, a mathematical model was developed to analyze the hydroforming process of a long anisotropic circular tube into a square crosssection die. By using the thickness variation in two extreme cases of friction between the tube and die wall, namely no friction and sticking friction cases, thickness variation in the case of sticking friction was captured in the model. Then by using equilibrium equation for contact length segment, thickness distribution was determined and corresponding forming pressure is predicted. It was shown that in a plane strain state, anisotropic value has no influence on thickness variation of the deformed tube and the forming pressure will increase when the anisotropic value increases. The analytical results of forming pressures and thickness distributions were compared with the results available in theliterature to verify the validity of this simple analytical proposed model.
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41


H.
Haghighat
Mechanical Engineering Department, Razi University, Kermanshah, Iran.
Mechanical Engineering Department, Razi University
Iran
hhaghighat@razi.ac.ir


A.
Janghorban
Mechanical Engineering Department, Razi University, Kermanshah, Iran.
Mechanical Engineering Department, Razi University
Iran
Tube hydroforming
Anisotropic
Square crosssection die
[[1] J. Chen, Z. Xia, S. Tang, Corner fill modeling of tube hydroforming. Proceedings of the ASME, Manufacturing in Engineering Division, 11 (2000) 635640.##[2] G. Kridli, L. Bao, P. Mallick, Twodimensional plane strain modeling of tube hydroforming. Proceedings of the ASME, Manufacturing in Engineering Division, 11 (2000) 629634.##[3] Y. Hwang, T. Altan, Finite element analysis of tube hydroforming processes in a rectangular die, Finite. Elem. Anal. Des., 39 (2002) 10711082.##[4] F. Vollertson, M. Plancak, On the possibilities for the determination of the coefficient of friction in the hydroforming of tubes. J. Mater. Process. Technol., 1125/1126 (2002) 412420.##[5] G.T. Kridli, L. Bao, P.K. Mallick, Y. Tian, Investigation of thickness variation and corner filling in tube hydroforoming, J. Mater. Process. Technol., 133 (2003) 287296.##[6] G. Liu, S. Yuan, B. Teng, Analysis of thinning at the transition corner in tube hydroforming, J. Mater. Process. Technol., 177 (2006) 688691.##[7] Y.M. Hwang, W.C. Chen, Analysis and finite element simulation of tube expansion in a rectangular crosssectional die, Proceedings of the Institution of Mechanical Engineers, Part B: J. Eng. Manufact., 217 (2003) 127135.##[8] Y.M. Hwang, W.C. Chen, Analysis of tube hydroforming in a square crosssectional die. Int. J. Plasticity., 21 (2005) 18151833.##[9] J.H. Orban, S.J. Hu, Analytical modeling of wall thinning during corner filling in structural tube hydroforming, J. Mater. Process. Technol., 194 (2007) 714.##[10] J.E. Miller, S. Kyriakides, A.H. Bastard, On bendstretch forming of aluminum extruded tubes I: experiments, Int. J. Mech. Sci. 43 (2001) 12831317.##[11] J.E. Miller, S. Kyriakides, E. Corona, On bendstretch forming of aluminum extruded tubes II: analysis, Int. J. Mech. Sci., 43 (2001) 13191338.##[12] E. Corona, A simple analysis for bendstretch forming of aluminum extrusions, Int. J. Mech. Sci., 46 (2004) 433448.##[13] Y. Guan, F. Pourboghrat, Fourier series based finite element analysis of tube Hydroforminggeneralized plane strain model, J. Mater. Process. Technol., 197 (2008) 379392.##[14] Y. Guan, F. Pourboghrat, W. Yu, Fourier series based finite element analysis of tube hydroformingan axisymmetric model, Eng. Computations., 23 (2008) 697728.##[15] L.M. Smith, J.J. Caveney, T. Sun, Fundamental concepts for corner forming limit diagrams and closedform formulas for planar tube hydroforming analysis, J. Manufact. Sci. Eng., 128 (2006) 874883.##[16] L.M. Smith, T. Sun, A nonfinite element approach for tubular hydroforming simulation featuring a new sticking friction model, J. Mater. Process. Technol., 171 (2006) 214222.##[17] C. Yang, G. Ngaile, Analytical model for planar tube hydroforming: Prediction of formed shape, corner fill, wall thinning, and forming pressure, Int. J. Mech. Sci., 50 (2008) 12631279.##[18] Z. Marciniak, J.L. Duncan, S.J. Hu, Mechanics of Sheet Metal Forming, second ed., Butter worth Heinemann, 2002. ##]
An Approach to Designing a Dual Frequency Piezoelectric Ultrasonic Transducer
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2
This paper has been devoted to such approach for designed and fabricated the dual frequency piezoelectric ultrasonic transducer having longitudinal vibrations for high power application. By using analytical analysis, the resonance frequency equations of the transducer in the halfwave and the allwave vibrational modes were determined for the assumed first resonance frequency of 25kHz. According to the resonance frequency equation, four transducers with two different constructions (Type A and B) were designed and made. The finite element method provided by commercial ANSYS was employed for FEM modeling and analysis of the transducer to observe its vibration behavior. It was shown that there is a good agreement between the experimental and FEM results. The designed and fabricated transducer can be excited to vibrate at two resonance frequencies, which correspond to the halfwave and the allwave vibrational modes of the transducer, and use of Type B transducer greatly increased the mechanical quality factor (Q) of piezoelectric transducers.
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A.
Pak
Mechanical Engineering Department, Faculty of Engineering, BuAli Sina University, Hamedan, Iran.
Mechanical Engineering Department, Faculty
Iran
a.pak@basu.ac.ir


A.
Abdullah
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran
Department of Mechanical Engineering, Amirkabir
Iran
abdullah.amir@gmail.com
Dual frequency ultrasonic transducer
High power ultrasonic
FEM simulation
Ultrasonic cleaning
[[1] L. Shuyu, Study on the multifrequency Langevin ultrasonic transducer, Ultrasonics, 33(6) (1995) 445448.##[2] Y.R. Yeonbo Kim, New design of matching layers for high power and wide band ultrasonic transducers, Sensor. Actuator., 71 (1998) 116122.##[3] L. Parrini, Design of advanced ultrasonic transducers for welding devices, IEEE Trans. Ultrason., Ferroelect., Freq. Control., 48(6) (2001) 16321639.##[4] B. Dubus, G. Haw, C. Granger, O. Ledez, Characterization of multilayered piezoelectric ceramics for high power transducers, Ultrasonics, 40 (2002) 903906.##[5] H.L.W. Chan, M.W. Ng, P.C.K. Liu, Effect of hybrid structure (1/3 composite and ceramic) on the performance of sandwich transducers, Mat. Sci. Eng., B99 (2003) 610.##[6] S. Saitoh, M. Izumi, Y. Mine, A dual frequency ultrasonic probe for medical applications, IEEE Trans. Ultrason. Ferroelectr. Freq. Control, 42 (1995) 294300.##[7] G. Piazza, P.J. Stephanou, A. Pisano, Singlechip multiplefrequency AlN MEMS filters based on contourmode piezoelectric resonators, J. Microelectromech. Syst., 16 (2007) 31928.##[8] K. Heath Martin, B.D. Lindsey, J. Ma, M. Lee, S. Li, F.S. Foster , X. Jiang, P.A. Dayton, Dualfrequency piezoelectric transducers for contrast enhanced ultrasound imaging, Sensors, 14 (2014) 2082520842.##[9] S. Lin, C. Xu, Analysis of the sandwich ultrasonic transducer with two sets of piezoelectric elements, Smart. Mater. Struct., 17(6) (2008) 6 065008. ##[10] S. Lin, An improved cymbal transducer with combined piezoelectric ceramic ring and metal ring, Sensor. Actuator., 163(1) (2010) 266276.##[11] S. Lin, L. Xu, H. Wenxu, A new type of high power composite ultrasonic transducer, J. Sound. Vib., 330(7) (2011) 14191431.##[12] S¸. Deniz, The design of a multifrequency underwater acoustic transducer with cylindrical piezoelectric elements, MSc Thesis. Turkey: Middle East Technical University; 2011.##[13] T. Asami, H. Miura, Longitudinaltorsional vibration source consisting of two transducers with different vibration modes, JPN. J. Appl. Phys., 55 (2016) 78.##[14] J.W. Rayleigh, The Theory of Sound, New York, 1945.##[15] K.F. Graff, Wave Motion in Elastic Solids, Oxford University Press, 1975.##[16] R.G. Grimes, J.G. Lewis, H.D. Simon, A shifted block lanczos algorithm for solving sparse systematic generalized eigenproblems, Siam. J. Matrix. Anal. Appl., 15 (1994) 228272.##[17] Piezoelectric Ceramics for High Power Applications data sheet, TAMURA CO., 2006.##[18] G.W. Taylor., J.J. Gagnepain, Piezoelectricity, New York: Gordon and Breach Science, 4 (1960).##]
Failure Mechanism and Ultimate Strength of Friction Stir Spot Welded Al5052 Joints under Tensileshear Loading
2
2
In this paper failure mechanism of a joint which was welded by friction stir spot welding method was studied. The 5052 aluminum joint was loaded under tensileshear condition.To find out failure mechanism, several tests were conducted such as: strainstress, macrography, and Vickers hardness. Results of strainstress test state the stages of failure and crack initiation and propagation. Macrography analysis was done in several stages with different penetration depths. It was shown that the material flow, the critical surface of the coupon, and the determined zones were more possible to generate crack. Finally, by using Vickers hardness test, the susceptible zones to crack generation and propagation can be specified.
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61


M.H.
Salimi
Mechanical Engineering Department, K.N. Toosi University of Technology, Tehran, Iran.
Mechanical Engineering Department, K.N. Toosi
Iran
mhsalimi92@yahoo.com


M.
Assadollahi
Mechanical Engineering Department, K.N. Toosi University of Technology, Tehran, Iran.
Mechanical Engineering Department, K.N. Toosi
Iran
morteza_assadollahi@yahoo.com


S.
Nakhodchi
Mechanical Engineering Department, K.N. Toosi University of Technology, Tehran, Iran.
Mechanical Engineering Department, K.N. Toosi
Iran
snakhodchi@kntu.ac.ir
FSSW
Failure mechanism
analysis
tensileshear load
[[1] D. Kim, Resistance spot welding of aluminum alloy sheet 5J32 using SCR type and inverter type power supplie, Mat. Sci. Eng., 38 (2009) 5560.##[2] L. Han, M. Thornton, M. Shergold, A comparison of the mechanical behaviour of selfpiercing riveted and resistance spot welded aluminium sheets for the automotive industry, Mater. Design., 31 (2010) 14571467.##[3] A. Gean, Static and fatigue behavior of spotwelded 51820 aluminum alloy sheet, Weld. J., 78 (1999) 8088.##[4] Y. Tozaki, Y. Uematsu, K. Tokaji, Effect of tool geometry on microstructure and static strength in friction stir spot welded aluminium alloys, Int. J. Mach. Tool. Manu., 47 (2007) 22302236.##[5] Y. Uematsu, K. Tokaji, Comparison of fatigue behaviour between resistance spot and friction stir spot welded aluminium alloy sheets, Sci. Technol. Weld. Joi., 14 (2009) 6271.##[6] D. Choi, Formation of intermetallic compounds in Al and Mg alloy interface during friction stir spot welding, Intermetallics, 19 (2011) 125130.##[7] A. Gerlich, P. Su, T. North, Tool penetration during friction stir spot welding of Al and Mg alloys, J. Mater. Sci., 40 (2005) 64736481.##[8] K. MuciK¨ uchler, S. Kalagara, W.J. Arbegast, Simulation of a refill friction stir spot welding process using a fully coupled thermomechanical FEM model. J. Manuf. Sci., 132 (2010) 145155.##[9] M. Bilici, A.I. Ykler, Influence of tool geometry and process parameters on macrostructure and static strength in friction stir spot welded polyethylene sheets. Mater. Design., 33 (2012) 145152.##[10] M. Merzoug, Parametric studies of the process of friction spot stir welding of aluminium 6060T5 alloys. Mater. Design., 31 (2010) 30233028.##[11] Y. Yin, A. Ikuta, T. North, Microstructural features and mechanical properties of AM60 and AZ31 friction stir spot welds. Mater. Design., 31 (2010) 47644776.##[12] S. Thoppul, R.F. Gibson, Mechanical characterization of spot friction stir welded joints in aluminum alloys by combined experimental/numerical approaches: Part I: Micromechanical studies. Mater. Charact., 60 (2011) 13421351.##[13] M. Kurtulmus, Friction stir spot welding parameters for polypropylene sheets. Sci. Res. Essays., 7 (2012) 947956.##[14] S. Jambhale, S. Kumar, S. Kumar, Effect of process parameters & tool geometries on properties of friction stir spot welds: a review, J. Eng. Sci., 3 (2015) 611.##[15] S. Siddharth, T. Senthilkumar, Study of Friction Stir Spot Welding Process and its Parameters for Increasing Strength of Dissimilar Joints, JSA, 5 (2011) 144150.##[16] W. Yuan, Friction stir spot welding of aluminum alloys, JSA, 1 (2008) 1018.##[17] D. Klobˇcar, Parametric study of friction stir spot welding of aluminium alloy 5754. Metalurgija, 53 (2014) 2124.##[18] C. Jonckheere, Fracture and mechanical properties of friction stir spot welds in 6063T6 aluminum alloy, Int. J. Adv. Manuf. Tech., 62 (2012) 569575.##[19] G. Buffa, L. Fratini, M. Piacentini, On the influence of tool path in friction stir spot welding of aluminum alloys. J. Mater. Process. Tech., 208 (2008) 309317.##[20] Q. Yang, Material flow during friction stir spot welding. Mater. Sci. Eng., 527 (2010) 43894398.##[21] A. Malafaia, Fatigue behavior of friction stir spot welding and riveted joints in an Al alloy, Proc. Eng., 2 (2010) 18151821.##[22] S. Arul, Experimental study of joint performance in spot friction welding of 6111T4 aluminium alloy, Sci. Technol. Weld. Joi., 13 (2008) 629637.##23] H. Badarinarayan, Effect of tool geometry on hook formation and static strength of friction stir spot welded aluminum 5754O sheets, Int. J. Mach. Tool. Manu., 49 (2009) 814823.##[24] S. Baek, Microstructure and mechanical properties of friction stir spot welded galvanized steel, Mater. T., 51 (2010) 10441050.##[25] S. Baek, Structureproperties relations in friction stir spot welded low carbon steel sheets for light weight automobile body, Mater. T., 51 (2010) 399403.##[26] T. Freeney, S. Sharma, R. Mishra, Effect of welding parameters on properties of 5052 Al friction stir spot welds, SAE Technical Paper, 150 (2008) 171191.##[27] Z. Zhang, Effect of welding parameters on microstructure and mechanical properties of friction stir spot welded 5052 aluminum alloy, Mater. Design., 32 (2011) 44614470.##[28] Y. Tozaki, Y. Uematsu, K. Yokaji. Effect of welding condition on tensile strength of dissimilar friction stir spot welds between different aluminum alloys. in 6th International Symposium on Friction Stir Welding (ISFSW6), Montreal, QC, Canada, Oct. 2006.##[29] F. Hunt, H. Badarinarayan, K. Okamoto, Design of Experiments for Friction Stir Stitch Welding of Aluminum Alloy 6022T4Friction Stir Welding of Aluminum for Automotive Applications, SAE Technical Paper, 142 (2006) 8493.##[30] V. Tran, J. Pan, T. Pan, Effects of processing time on strengths and failure modes of dissimilar spot friction welds between aluminum 5754O and 7075T6 sheets. J. Mater. Process. Tech., 209 (2009) 37243739.##[31] S. Sato, Characteristics of the kissingbond in friction stir welded Al alloy 1050. Mat. Sci. Eng., 405 (2005) 333338.##]