@article { author = {Alavi Nia, A. and Shirazi, A.}, title = {A Numerical and Experimental Investigation into the Effect of Welding Parameters on Thermal History in Friction Stir Welded Copper Sheets}, journal = {Journal of Stress Analysis}, volume = {2}, number = {1}, pages = {1-9}, year = {2017}, publisher = {Bu-Ali Sina University}, issn = {2588-2597}, eissn = {2588-3054}, doi = {10.22084/jrstan.2017.12687.1016}, abstract = {One of the important issues in the process of Friction Stir Welding (FSW) is to determine the thermal history and its distribution in the work piece during the welding process. Several analytical and empirical relations have been suggested to estimate the amount of heat transferred to the work piece; one of the relations is Frigaad relation. In the present study, thermal history was determined for joined parts of copper sheets under various welding conditions by Frigaad relation and numerical method. Furthermore, results were compared with the experimental results which had a good agreement with numerical results. In addition, the thermal field was also determined for any welding conditions and at any given moment. By conducting this study, it is evident that the traverse velocity change mainly affects the amount oftransferred heat and change in rotational speed dramatically changes the temperature of the process.}, keywords = {Friction stir welding,Finite element,Copper,Thermal history,Welding parameters}, url = {https://jrstan.basu.ac.ir/article_2006.html}, eprint = {https://jrstan.basu.ac.ir/article_2006_5531568123c61cba685628538f8aa79c.pdf} } @article { author = {Farahinezhad, E. and Nouri, A. and Hosseinian, E.}, title = {Coupled Thermoelastic Analysis of Semi-elliptical Crack in Thick-walled Cylinder Considering Green-Lindsay and Green-Naghdi Type II Theories}, journal = {Journal of Stress Analysis}, volume = {2}, number = {1}, pages = {11-26}, year = {2017}, publisher = {Bu-Ali Sina University}, issn = {2588-2597}, eissn = {2588-3054}, doi = {10.22084/jrstan.2017.12717.1017}, abstract = {In this paper, the stress intensity factors for semi-elliptical cracks in a homogeneous isotropic cylinder have been determined. Athick-walled cylinder is subjected to a one-dimensional axisymmetric thermal shock on the outer surface according to the classic thermo elasticity (CTE), Green-Lindsay (G-L), and Green-Naghdi (G-N) theories. The effect of temperature-strain coupling and the effect of inertia term in governing equations are considered. The semi-elliptical crack stress intensity factors (SIFs) at the deepest and surface pointsare determined using weight function method. The comparison between the temperature, stress, and SIF obtained from CTE, G-L, and G-N theories shows the different behavior of generalized theories and CTE. By considering relaxation times, prediction of higher temperature and stress values, in contrast to CTE theory, will be resulted. Furthermore, the SIF resulted from generalized theories is significantly higher than CTE theory. The temperature, stress, and maximum SIF obtained for G-N II is higher than G-L theory.}, keywords = {Green-Naghdi theory,Green-Lindsay theory,Weight function method,Thermal shock,Semi-elliptical crack in cylinder}, url = {https://jrstan.basu.ac.ir/article_2007.html}, eprint = {https://jrstan.basu.ac.ir/article_2007_33c812ce9558c10a672bd28a51dbd856.pdf} } @article { author = {Khorshidi, K. and Fallah, A.}, title = {Effect of Exponential Stress Resultant on Buckling Response of Functionally Graded Rectangular Plates}, journal = {Journal of Stress Analysis}, volume = {2}, number = {1}, pages = {27-33}, year = {2017}, publisher = {Bu-Ali Sina University}, issn = {2588-2597}, eissn = {2588-3054}, doi = {10.22084/jrstan.2017.12894.1019}, abstract = {The effect of exponential stress resultant on buckling response of functionally graded rectangular plates based on exponential shear deformation theory is investigated in this paper. In exponential shear deformation theory, exponential functions are used in terms of thickness coordinate to include the effect of the transverse shear deformation and rotary inertia. The material properties of the functionally graded plate are assumed to vary according to a power low form according to the thickness direction. The equations of motions are derived based on Hamiltons principle. To validate the formulations, present results in specific cases are compared with available results in literature and good agreement could be seen. Finally, the influence of different parameters like power law indexes, aspect ratio, and the thickness ratio on the non-dimensional critical buckling load of rectangular FG plates are presented and discussed in detail.}, keywords = {Buckling,Functionally graded,Rectangular plate,Navier}, url = {https://jrstan.basu.ac.ir/article_2008.html}, eprint = {https://jrstan.basu.ac.ir/article_2008_9ba3288a8b1e361a1d6306a3293a6c96.pdf} } @article { author = {Hassani, A. and Gholami, M.}, title = {Analytical and Numerical Bending Solutions for Thermoelastic Functionally Graded Rotating Disks with Nonuniform Thickness Based on Mindlin’s Theory}, journal = {Journal of Stress Analysis}, volume = {2}, number = {1}, pages = {35-49}, year = {2017}, publisher = {Bu-Ali Sina University}, issn = {2588-2597}, eissn = {2588-3054}, doi = {10.22084/jrstan.2017.13316.1021}, abstract = {In this paper, analytical and numerical solutions for thermoelastic functionally graded (FG) rotating disks with non-uniform thickness under lateral pressure are studied. The study is performed based on Mindlin’s theory. Considering the fact that bending and thermal loadings in analysis of rotating disk are necessary to study the components such as brake and clutch disks. The governing differential equations arising from FG rotating disk are firstly extracted. Then, Liao’s homotopy analysis method (HAM) and Adomian’s decomposition method (ADM) are applied as two analytical approaches. Calculation of stress components and then comparison of the results of HAM and ADM with Runge-Kutta’s and FEM are performed to survey compatibility of their results. The distributions of radial and circumferential stresses of rotating disks are studied and discussed. Finaly, the effects of temperature, grading index, angular velocity and lateral loading on the components of displacement and stresses are presented and discussed, in detail.}, keywords = {Uniform thickness functionally graded rotating disk,Thermoelastic bending loading,Homotopy analysis method,Adomian’s decomposition method}, url = {https://jrstan.basu.ac.ir/article_2009.html}, eprint = {https://jrstan.basu.ac.ir/article_2009_877fd8e3ab5dbdfa2435781d63857d2d.pdf} } @article { author = {Nourbakhsh, S.H. and Atrian, A.}, title = {Effect of Submerged Multi-pass Friction Stir Process on the Mechanical and Microstructural Properties of Al7075 Alloy}, journal = {Journal of Stress Analysis}, volume = {2}, number = {1}, pages = {51-56}, year = {2017}, publisher = {Bu-Ali Sina University}, issn = {2588-2597}, eissn = {2588-3054}, doi = {10.22084/jrstan.2017.14013.1022}, abstract = {The friction stir process (FSP) is a solid-state process which is used for severe plastic deformation of materials and modification in microstructure. The microstructure evolution, which iscaused by dynamic recrystallization, changes the mechanical properties of the material. In this study, the FSP of the surface of Al7075 alloy is carried out using 0% overlapping of passes. The FSP caused the non-uniform structure of the raw material with an average grain size of 18 micrometers to change into a uniform structure. This process refined the structure to the grain size of about 8.2 and 12.1 micrometersfor overlapped regions in water and air respectively. In order to study the mechanical properties, the tensile specimens were prepared in both parallel and perpendicular directions to the pin motion. Results showed an improvement in the yield stress, ultimate stress, and elongation of the specimens after FSP. Furtheremore, Vickers hardness of the overlapping specimens decreased compared to the raw materials after applying the FSP.}, keywords = {Friction stir process (FSP),Submerged,Overlap,Al7075,Characterization}, url = {https://jrstan.basu.ac.ir/article_2010.html}, eprint = {https://jrstan.basu.ac.ir/article_2010_4ff9e53aa29d688490f9a18a56b00fd9.pdf} } @article { author = {Habibi, N. and Asadi, S. and Moradikhah, R.}, title = {Evaluation of SIF in FGM Thick-walled Cylindrical Vessel}, journal = {Journal of Stress Analysis}, volume = {2}, number = {1}, pages = {57-68}, year = {2017}, publisher = {Bu-Ali Sina University}, issn = {2588-2597}, eissn = {2588-3054}, doi = {10.22084/jrstan.2017.14362.1026}, abstract = {In the present research, an internal semi-elliptical surface crack in a FGM thick-walled cylindrical vessel under internal pressure is assumed. The Poisson ratio is constant throughout the vessel and the material is considered to be isotropic with exponentially varying elastic modulus. The KI is calculated using the BEM and FEM for different values of the relative depths of crack and material gradients. The research results show that increasing the E2/E1, decreases SIF and when E2/E1 = 10, the SIF of the FGM vessel is often lower than the corresponding homogeneous vessel. It can be observed that the relation between KI and internal pressure in FGM is linear as for homogeneous materials, so that increasing internal pressure KI increase as the same. The obtained results of BEM and FEM methods show that good agreement between the results can be seen.}, keywords = {FGM,BEM,Stress intensity factor,Pressure vessel,XFEM,FM}, url = {https://jrstan.basu.ac.ir/article_2011.html}, eprint = {https://jrstan.basu.ac.ir/article_2011_a3b317b36b2b70949b7cc48640bc3a0d.pdf} }