Vibration of sumberged functionally graded cylindrical shell based on first order shear deformation theory using wave propagation method

Hossein Farahani,Farzan Barati 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.3

This paper focuses on vibration analysis of functionally graded cylindrical shell submerged in an incompressible fluid. The equation is established considering axial and lateral hydrostatic pressure based on first order shear deformation theory of shell motion using the wave propagation approach and classic Flügge shell equations. To study accuracy of the present analysis, a comparison carried out with a known data and the finite element package ABAQUS. With this method the effects of shell parameters, m, n, h/R, L/R, different boundary conditions and different power-law exponent of material of functionally graded cylindrical shells, on the frequencies are investigated. The results obtained from the present approach show good agreement with published results.

Vibration of sumberged functionally graded cylindrical shell based on first order shear deformation theory using wave propagation method

Farahani, Hossein,Barati, Farzan Techno-Press 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.53 No.3

This paper focuses on vibration analysis of functionally graded cylindrical shell submerged in an incompressible fluid. The equation is established considering axial and lateral hydrostatic pressure based on first order shear deformation theory of shell motion using the wave propagation approach and classic Fl$\ddot{u}$gge shell equations. To study accuracy of the present analysis, a comparison carried out with a known data and the finite element package ABAQUS. With this method the effects of shell parameters, m, n, h/R, L/R, different boundary conditions and different power-law exponent of material of functionally graded cylindrical shells, on the frequencies are investigated. The results obtained from the present approach show good agreement with published results.

In-vitro experimental analysis of magnetic fluid hyperthermia in soft tissue with artificial blood perfusion

Mohammad Mahdi Attar,Farzan Barati,Gita Rezaei,Behroz Adelinia 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1

Magnetic fluid exposed to an alternating magnetic field generates heat that it can be used for treatment and removal of cancerous tissue. The aim of this study is to investigate the thermal behavior of kidney tissue in magnetic fluid hyperthermia. Considering the fact that doing experiments on live tissue have some limitations, a new method is provided to test on dead tissue. In this study, an artificial circulation of the current vessels of kidney is used to make closer the behavior of dead tissue to live ones. The superparamagnetic nanoparticles with an average diameter of 20 nm have been used to heat tissue and an overview of the hardware devices needed to generate a magnetic field and to record temperature has been mentioned. Finally, the heating process has been simulated by the finite element software of Ansys. The nanoparticles injected to the tissue have a relatively spherical distribution which inevitably increases with increasing the intensity of the magnetic field and temperature difference dose. On the other hand it was observed that the rate of blood flow plays a key role in the analysis of tissue behavior and it is able to decrease the rise in temperature at most 70 %. Based on the results, it is inferred that the circulation along magnetic field intensity and dose of nanoparticles, plays a key role in the process of heating the tissue.

Failure analysis of unidirectional polymeric matrix composites with two serial pin loaded-holes

Mohammad Mahdi Attar,Farzan Barati,Mahdi Ahmadpour,Ehsan Rezapour 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.6

The objective of this study is to investigate the effects of geometrical and physical parameters on failure modes and failure loads in unidirectional polymeric matrix composites with two serial pin loaded holes, analytically and experimentally. It is assumed that all of unidirectional fibers in the laminate lie in one direction while loaded by a load p 0 at infinity, parallel to the direction of the fibers. To derive equilibrium equations based on a Shear-Lag theory, a rectangular arrangement of fibers is considered and with the proper use of boundary and boundness conditions, stress and displacement fields are computed within the laminate, along with the surrounding pinholes. Finally by using the Hashin criterion failure modes and failure loads are estimated. To validate analytical results based on shear-lag theory, an experimental program is carried out. A very good agreement is observed between two procedures. Based on results, in small sizes of two pins, the dominant failure mode is bearing and with the increasing of hole sizes, failure modes are changed to tension and shear modes.

Stress concentration around of pin-loaded hole in unidirectional multi-layered metallic matrix composite material

Sajjad Dehghanpour,Keivan Hosseini Safari,Farzan Barati,Mohammadmahdi Attar 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.10

The objective of this study is to examine the stress concentration factor around a pin-loaded hole in a metallic matrix composite material, analytically and numerically. It is assumed that all unidirectional fibers lie in the metallic matrix while the shear stress in fibers is discarded. To generally derive the equilibrium equation for all fibers and the metallic matrix, the previous shear-lag theory had been improved and the extension in the metallic matrix was considered. Afterwards, the equilibrium equation was solved by the eigenvalue method while the displacement field and stress distribution around the pin-loaded hole were computed. Having calculated stress concentration factors and the displacement field in a unidirectional multi-layered composite material, we compared the analytical results with those numerical values from other references. Additionally, the effect of the pin’s diameter, as well as the edge-hole distance on maximum stress concentration factor was investigated. To recapitulate, it is seen that the modified shear-lag theory can simulate the mechanism of the load transfer between metallic matrices.

Analysis of nonlinear bioheat transfer equation in magnetic fluid hyperthermia

Zahed Zomordikhani,Mohammad Mahdi Attar,Alireza Jahangiri,Farzan Barati 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.9

The objective of this study is to examine the role of blood perfusion in magnetic fluid hyperthermia by drug delivery. Although increasing blood perfusion due to high local temperature difference refers to the intelligent response of the human body, some researchers are accustomed to employing a constant rate of blood perfusion in the bioheat transfer equation. In this study, we considered a variable volumetric rate for blood perfusion in tissue, experimentally and numerically by Galerkin method. To validate the results obtained from numerical methods, an experimental procedure proposed. Furthermore, in order to transfer magnetic fluid by drug delivery, infusion pomp by which the saline serum with nanoparticles through the vein and artery was employed to make a spherical distribution in tissue. This circulation made it possible to transfer nanoparticles to tissue without any injection. After 60 minutes and changing the dark color of the saline serum to light clear, high amount of nanoparticles (about 90 %) was transferred to the tissue. After slicing the tissue, the rather spherical distribution of nanoparticles may be illustrated. Afterward, that circulation at the rate equal to blood perfusion has been made to simulate blood perfusion in dead tissue. To measure temperature, seven Lm35 sensors have been inserted into the tissue to report temperature differences. Based on results, there was seen a significant change in hyperthermic temperature difference in comparison with results obtained from Pennes' bioheat transfer equation. Additionally, a difference of about 5-10 % was seen between numerical and experimental results.

Repairing cracked aluminum plates by aluminum patch using diffusion method

Sobhan Dehghanpour,Alireza Nezamabadi,Mohammad Mahdi Attar,Farzan Barati,Mehdi Tajdari 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.10

The aim of this work is to scrutinize the importance of diffusion bonding temperature, pressure and time on the repair of a cracked aluminum plate while the maximum tensile strength under a quasi-static loading has been investigated. The diffusion method was used to connect aluminum patches to repair the central and mode I cracks in thin aluminum plates. Here, the process of repairing cracked pieces made of aluminum or aluminum alloys involved a chemical and mechanical step to remove aluminum oxide and press the patch and piece under the temperature difference at a certain time. The repaired pieces underwent a quasi-static tensile loading while the maximum tolerable amount of force was obtained in different situations. Having assigned five temperatures, 300, 400, 500, 550 and 600 ° C, as well as four test times 30, 60, 120 and 180 min and five different pressures 10, 20, 50, 80 and 110 bar, we utilized fractional factorial design approach to perform 40 tests while there was seen a 10 mm initial crack in repaired samples . Experimental results showed that the optimum connection was resulted at 550 °C and the pressure of 80 bars within 120 min where the maximum force tolerated by the repaired vs. the unrepaired piece increased by 92 %. Therefore, having weighed the repair method using the diffusion bonding, we suggest that this type of the repair method can be a proper and cheap alternative to composite and adhesive patches.