Search published articles


Showing 3 results for sadough vanini
Analytical modeling of fracture toughness JIC of austenitic–martensitic functionally graded steels with crack arrester layers
Seyed Ali sadough vanini, Meisam Moori Shirbani,
Volume 13, Issue 11 (1-2014)
Abstract
In this article, fracture toughness of austenitic–martensitic functionally graded steels fabricated by electroslag remelting with crack arrester layers is investigated by experimental and analytical methods. The material contains austenite phase in addition to martensite layer. The Young’s modulus and the Poisson’s ratio have been assumed to be constant, while other mechanical properties like the yield strength and the strain hardening exponent vary exponentially along the specimen width. In analytical case, unloading compliance method is modified to calculate the critical value of J-integral for cracked three point bend specimens while standard specimens with different crack lengths are tested in experiments. The effect of crack length on the fracture toughness has been studied. It is observed that, as the crack tip goes toward a martensite layer, fracture toughness of the specimen decreases considerably. The obtained results from the proposed model are in good agreement with the experimental results.
The Extended Finite Element Method Numerical and Experimental Analysis of Mechanical Behavior of Polysulfone/58s Bioactive Glass Synthesized through Solvent Casting Method
A. Pazhouheshgar , A.h. Moghanian , S.a. sadough vanini,
Volume 20, Issue 8 (August 2020)
Abstract
The composites derived from the bioactive glasses, such as BG/polysulfone, have better mechanical properties than pure materials and their characteristics are closer to human bone. In this study, the unknown fracture behavior of 58s BG/PSF composite has been investigated. The extended finite element method (XFEM) was used, in order to model the fracture behavior of 58s BG/PSF composite with greater accuracy. The XFEM doesn’t require remeshing at each step and achieves the precise approximation of singularities by incorporating discontinuity behavior into the elements using the enrichment functions. The aim of using the XFEM was to obtain stress intensity factors, displacements, stress and strain around the crack tip, fracture toughness as well as strain energy release rate. Moreover, the 58s BG/PSF composite with 30% bioactive glass particles was synthesized using solvent casting method and the bending failure test was performed according to the relevant standard. Also, to demonstrate the quality of the interface between the glass particles and polysulfone, SEM investigation was performed on the fracture surface. The obtained fracture toughness was in the range of 1.4 to 1.6 , and the strain energy release rate was in the range of 1600 to 1900 J.m-2, which was comparable to the same properties of natural human bone. Besides, the stress intensity factors and strain energy release rates were calculated by coding in MATLAB and modeling in ABAQUS, and the numerical results were validated with the analytical and experimental data and it was revealed that the numerical results were in great coordinance with the analytical and experimental results.

Influence of the process parameters on induced residual stress by ultrasonic needle peening on Al6061alloy
Mehdi Lak, Seyed Ali sadough vanini, Ali Ghasemi,
Volume 21, Issue 2 (February 2021)
Abstract
 
Abstract
Ultrasonic needle penning is a modern technique that enhances the surface properties of metallic components by imposing static and dynamic loadings. The efficiency of this technique dramatically is dependent on the process parameters. In this study an experimental and numerical investigation on ultrasonic needle penning was carried out. The numerically predicted residual stress profile was verified using X-ray diffraction measurement of residual stress. A 3D finite element model of ultrasonic needle penning was simulated by ABAQUS software. Moreover, a parametric study was performed to investigate the effects of needle diameter, amplitude, device moving speed and static force on residual stress distribution. In order to design of experiments and determine the optimized process parameters of ultrasonic needle penning, Taguchi’s method was implemented. Based on the results, needle diameter had the lowest impact on maximum compressive residual stress and residual stress increases by increasing amplitude and reducing device moving speed. The maximum residual stress was achieved for the needle diameter of 4mm, the amplitude of 16µm, the device moving speed of 1.5cm/s and the static force of 10N. For the optimum case, compressive residual stress was improved 24%.
Page 1 from 1