Showing 13 results for Finite Element
A. Hassani, R. Ravaee,
Volume 5, Issue 2 (6-2008)
Abstract
Abstract: To ensure the rail transportations safety, evaluation of fatigue behavior of the rail steel
is necessary. High cycle fatigue behaviour of a rail steel was the subject of investigation in this
research using fracture mechanics. Finite element method (FEM) was used for analyzing the
distribution of the stresses on the rail, exerted by the external load. FEM analysis showed that the
maximum longitudinal stresses occurred on the railhead. To find out about the relation of crack
growth with its critical size, and to estimate its lifetime, the behaviour of transverse cracks to rail
direction was studied using damage tolerance concept. It revealed that transverse crack growth
initially occurred slowly, but it accelerated once the crack size became larger. Residual service
life was calculated for defective segments of the rails. In addition, allowable crack size for
different non-destructive testing intervals was determined the allowable crack size decreased as
the NDT intervals increased.
S. A. Sajadi, R. Ebrahimi, M. M. Moshksar,
Volume 6, Issue 1 (3-2009)
Abstract
Abstract: In this paper, the forming process of a central hub by radial-forward extrusion is analyzed by using the finite
element software, ABAQUS. Radial-forward extrusion is used to produce hollow parts that generally feature a central
hub with radial protrusions. Effective design factors such as mandrel diameter, die corner radius, die fillet radius,
mandrel corner radius, tube wall thickness and frictional conditions on the force required are investigated by
simulation process. Commercially pure Aluminum AA1100 is selected as a model material for both experimental
investigation and simulation analysis. Comparison is made and good agreement between the experimental result and
that of finite element method is achieved.
Bahman Mirzakhani, Hossein Arabi, Mohammad Taghi Salehi,seyed Hossein Seyedein, Mohammad Reza Aboutalebi, Shahin Khoddam, Jilt Sietsma,
Volume 6, Issue 4 (12-2009)
Abstract
Abstract
Recovery and recrystallization phenomena and effects of microalloying elements on these phenomena are of great importance in designing thermomechanical processes of microalloyed steels. Thus, understanding and modeling of microstructure evolution during hot deformation leads to optimize the processing conditions and to improve the product properties.
In this study, finite element method was utilized to simulate thermomechanical parameters during hot deformation processes. FEM results then were integrated with physically based state variable models of static recovery and recrystallization combined with a realistic microstructural geometry. The thermodynamic software Thermo-calc was also used to predict present microalloying elements at equilibrium conditions.
The model performance was validated using stress relaxation tests. Parametric studies were carried out to evaluate the effects of deformation process parameters on the microstructure development following hot deformation of the API-X70 steel
M. Farzalipour Tabriz, M. Ghassemi Kakroudi*,
Volume 7, Issue 4 (10-2010)
Abstract
Abstract: Cordierite-Mullite based kiln furnitures are widely used in fast-firing of ceramic products because of their low thermal expansion which confer them a very good ability to thermal shock resistance. Difference in CTE of constituent phase can develop damage during thermal cycling due to internal stresses. Increase in industrial competitiveness leads to the development of new means for extending refractory life and increasing reliability of industrial tools so investigations regarding the structuralmechanical behaviour of refractory systems are becoming essential. In this paper, Thermo-mechanical design of commercial Cordierite-Mullite based kiln furniture was investigated by using finite element method (FEM) and possible solutions for improvement of working life have been considered. The results indicated that the change of the kiln furniture geometry can decrease the maximum thermomechanical stress in study conditions which can prolong the refractory service life. Obtained results indicate the existence of an optimal thickness for the section under maximum thermo-mechanical stress. Increasing filet radius of ring region from 3 to 9 mm decreases thermo-mechanical stress value from 113 to 93 MPa.
H. Ashrafi, M. Mahzoon, M. Shariyat,
Volume 9, Issue 1 (3-2012)
Abstract
Abstract: The boundary value problems involving contact are of the great importance in industries related to mechanical and materials engineering. These mixed problems are challenging since a priori unknown deformed surface of the material contacting a rigid indenter is to be determined as a part of the solution. Anisotropic solids represent an important class of engineering materials including crystals, woods, bones, thin solid films, polymer composites, etc. Contact analysis of an anisotropic media, however, is more difficult and is developed less completely in the literature. In this work, both analytical and computational studies of the contact treatment of a semi-infinite orthotropic material indented by a rigid spherical indenter have been considered in two different sections. This approach can be applied to determine the interfacial contact area and pressure distribution for three-dimensional orthotropic materials, and can then be used to calculate the resulting stress and strain fields of the media. Results presented herein can serve as benchmarks with which to compare solutions obtained by ANSYS commercial package.
A. M. Behagh, A. Fadaei Tehrani, H. R. Salimi Jazi, O. Behagh,
Volume 12, Issue 1 (3-2015)
Abstract
n this paper a finite element model has been proposed for evaluation of primary and secondary current
density values on the cathode surface in nickel electroplating operation of a revolving part. In addition, the capability
of presented electroplating simulation has been investigated in order to describe the electroplated thickness of the
nickel sulfate solution. Nickel electroplating experiments have been carried out. A good agreement between the
simulated and experimental results was found. Also the results showed that primary current density can describe the
general form of thickness distribution but the relative value of current density using secondary current density can
present better description of thickness distribution
E. Gharibshahiyan, A. Honarbakhsh Raouf,
Volume 13, Issue 4 (12-2016)
Abstract
Friction welding is widely used in various industries. In friction welding, heat is generated by conversion of mechanical energy into thermal energy at the interface the work pieces during pin rotation under pressure. A three-dimensional thermo mechanical simulation of friction stir welding (FSW) processes is carried out for Aluminium Alloys of 6061and 7050 where the simulation results are compared directly with the measured temperature histories during FSW after process. The objective of the present work is to study and predict the heat transient generated in alloy aluminium plate welded by FSW method. A three dimensional model was developed by LS-Dyna software and heat cycles have been proposed during the welding of aluminium alloys 6061 and 7050. In this research, the simulations were carried out with linear velocity in the range of 140 to 225 mm/min and pin rotational speeds of 390 and 500 rpm. Increase in pin rotational speed, from 390 to 500 rpm, resulted in greater temperatures which translated to rise of recorded temperature of top and bottom of the specimens. This is in turn to a wider HAZ. In addition, it was observed that raising the linear velocity had an opposite effect. Finally, results of experimental and numerical data were correlated and validated
E. Maleki, K. Reza Kashyzadeh,
Volume 14, Issue 4 (12-2017)
Abstract
Hardened nickel coating is widely used in many industrial applications and manufacturing processes because of its benefits in improving the corrosion fatigue life. It is clear that increasing the coating thickness provides good protection against corrosion. However, it reduces the fatigue life. Thus, applying a thin layer of coated nickel might give an acceptable corrosion protection with minimum loss of the fatigue life. In the present study, the effects of hardened nickel coating with different thicknesses on the fatigue behavior of CK45 mild steel were experimentally investigated. After conducting the experimental tests, we carried out two different modeling approaches of finite element method (FEM) and artificial neural network (ANN). In the FEM modeling, an attempt was made to analyze the fatigue of the components by modeling the interface phase between the base metal and coating more accurately and using the spring elements; ANNs were developed based on the back propagation (BP) error algorithm. The comparison of the obtained results from FEM and ANN modeling with the experimental values indicates that both of the modeling approaches were tuned finely.
M. Naseri, M. Alipour, A. Ghasemi, E. Davari,
Volume 15, Issue 1 (3-2018)
Abstract
One of the interesting state-of-the-art approaches to welding is the process of friction stir welding (FSW). In comparison with the fusion processes, FSW is an advantageous method as it is suitable for the non-fusion weldable alloys and polymeric materials joining. Regarding the materials pure solid state joining, it also provides joints with less distortion and enhanced mechanical properties. In the present work, a three-dimensional (3D) model based on finite element analysis was applied to study the thermal history and thermomechanical procedure in friction stir welding of high density polyethylene plate. The technique includes the tool mechanical reaction and the weld material thermomechanical procedure. The considered heat source in the model, includes the friction among three items: the material, the probe and the shoulder. Finally, the model was validated by measuring actual temperatures near the weld nugget using thermocouples, and good agreement was obtained for studied materials and conditions.
M. Imran, R. Khan, S. Badshah,
Volume 16, Issue 1 (3-2019)
Abstract
Composite structures are widely used in many applications ranging from, but not limited to, aerospace industry, automotive, and marine structures due to their attractive mechanical properties like high strength to weight ratios. However composite structures needs utmost care during structures manufacturing and working conditions should be assessed prior to installation. One of the important defect in composite structures is delamination. Present work is focused on investigation of delamination effects on the natural frequencies of composite plate using commercial finite element software, ABAQUS. Analytical results were also analyzed using MATLAB code. Different stacking sequences and boundary conditions are considered for study in both analytical formulation and finite element analysis. Finite element results are compared with analytical results to validate the perfect composite plate. The natural frequency of the composite plate reduced with an increase in delamination size. Additionally, all-sides clamped composite plate showed higher values of natural frequency than other constraints in lower modes for symmetrical laminates. Natural frequency in cross ply laminates are higher for the simply supported composite plates. On comparison, results from both the techniques, finite element analysis and analytical analysis, were in good agreement.
F. Hosseinabadi, A. Rezaee-Bazzaz, M. Mazinani, B. Mohammad Sadeghi,
Volume 17, Issue 1 (3-2020)
Abstract
An experimental–numerical methodology was used in order to study the microstructural effects on stress state dependency of martensitic transformation kinetics in two different TRIP800 low alloy multiphase steels. Representative volume elements extracted from actual microstructure have been utilized for simulating the mechanical behavior of mentioned steels. The mechanical behavior for each constituent phases required in the model has been taken out from those reported in the literature. A stress invariant based transformation kinetics law has been used to predict the martensitic phase transformation during deformation. Crystallographic and thermodynamic theories of martensitic phase transformation have been utilized for estimating the constant parameters of the kinetics law, in a recently performed investigation, but the sensitivity of the transformation to the stress state remained as an adjusting parameter. The results of the current work show that the stress state sensitivity of martensitic phase transformation in the investigated steels is microstructure-dependent and the value of this parameter is almost equal to half of the bainite volume fraction. Therefore, the volume fraction of bainite in the low-alloy multiphase TRIP800 steels can be used as a first postulation for the value of the martensitic phase transformation sensitivity to the stress state and the microstructure based model previously developed for calculating the mechanical behavior of the TRIP800 steels can be utilized as a virtual design tool for development of TRIP steels having specific mechanical properties.
Yogesh Dewang, Vipin Sharma,
Volume 18, Issue 1 (3-2021)
Abstract
Finite element analysis has been carried out to investigate the effect of various parameters on axisymmetric hot extrusion process using aluminum alloy. The objective of the present work is to investigate the effect of friction coefficient, die angle, die-profile radius and predefined temperature of workpiece through FEM simulation of extrusion process. Nodal temperature distribution, heat flux, peak temperature at nodes and peak flux induced are identified as the output variables to assess the thermo-mechanical deformation behavior of aluminum alloy. Mesh sensitivity analysis is performed for the evaluation of mesh convergence as well as depicts the accuracy of present FEM model. Higher will be the coefficient of friction between interacting surfaces of die-billet assembly, more will be the increment in nodal temperature in billet. Higher will be the coefficient of friction, higher will be the generation of heat flux within billet, as this is achieved for highest coefficient of friction. Peak nodal temperature diminishes with increase in die profile radius nearly by 17 %.Maximum heat flux diminishes non-linearly by 30% with increase in die profile radius. Maximum nodal temperature increases nearly linearly by 14% with increment in predefined temperature of billet. Maximum heat flux decreases non-linearly by 5 % with increment in the initial temperature of workpiece. Validation of present numerical model is established on the basis of deformation behavior in terms of evolution of nodal temperature distribution upon comparison with previous studies available in literature.
Ali Ebrahimpour, Amir Mostafapour, Naeimeh Hagi,
Volume 20, Issue 1 (3-2023)
Abstract
In this research, the effect of RSW parameters including current intensity, welding time and welding force (coded by A, B and C) on the radius, thickness and area of the nugget and the radius of the HAZ of TRIP steel joints was investigated by DOE and RSM. A 3D coupled thermal-electrical-structural FEM was used to model RSW. To validate the FE model, two TRIP steel sheets were welded experimentally. During welding, the temperature was measured and the results were compared with the FE results and a good agreement was obtained. The boundaries of the welding zones were determined according to the critical temperatures and the responses in all samples were calculated. Using analysis of variance, direct, quadratic and interaction effects of parameters on the responses were studied and a mathematical model was obtained for each response. The direct linear effects of all parameters on all responses were significant. But among the interaction effects, the effect of B×C on the nugget radius, the effect of A×B on the nugget thickness, the effect of A×B on the nugget area and the effects of A×B and B×C on the HAZ radius were significant. Also, current intensity had the greatest effect on all responses.
