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fatigue-testing
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Geometrical Optimization of Aluminum Alloy Wheels for High Fatigue and Impact Strength
, M.Sc. Thesis Sharif University of Technology ; Khayyat, Ali Akbar (Supervisor) ; Pasharavesh, Abdolreza (Supervisor)
Abstract
After the rise of the automotive industry, aluminum wheels have superseded steel counterparts due to their numerous advantages. Foremost among these benefits is their reduced weight, leading to fuel savings and diminished environmental impact. Moreover, aluminum wheels offer enhanced aesthetics and greater strength in comparison to steel alternatives. This thesis focuses on the geometrical optimization of an aluminum wheel model conforming to the standards set by Iran's Department of Standards, aiming to achieve a higher strength-to-weight ratio. While prior research works have mainly focused on weight reduction while maintaining strength within approved standards, this thesis aims at the...
Experimental and Finite Element Analysis of Vehicle Steering Knuckle Fatigue Life under Road Driving Test
, M.Sc. Thesis Sharif University of Technology ; Farrahi, Gholamhossein (Supervisor)
Abstract
Steering Knuckle is a mechanical part in an automobile which connects the break, suspension system, hub, and steering system to the chassis. In the recent years due to the variant imposing forces on the steering knuckle this part’s fatigue life has attracted engineers and designers’ attention. The considered steering knuckle in this project is a steering knuckle from an Iranian car. The goal of this project is to determine the fatigue life of a steering knuckle under street loads. The fatigue life of a steering knuckle has been investigated with both experimental and finite element methods. In order to perform the fatigue test a test fixture was designed. The finite element analysis consists...
Effect of Different Defects of Spot Welded Joint in Automotive Body on Fatigue Strength: Experimental and Numerical Investigation
, M.Sc. Thesis Sharif University of Technology ; Farrahi, Gholamhossein (Supervisor) ; Mehmanparast, Ali (Supervisor) ; Reza Kashyzadeh, Kazem (Co-Supervisor)
Abstract
On average there are to resistance spot welding connections per vehicle. The quality of these welding directly affects the quality of the finished product and the strength of the vehicle against various loads, including road roughness, different maneuvers and even sudden impacts from accidents. During the spot welding process, unintentional failures occur due to the wrong choice of current, force and time. The aim of this study is to investigate the fatigue strength of three-sheets welding joints in numerical and laboratory methods, considering the defects of (Undersize weld, Stick, edge of sheet metal and Edge of sheet metal-SECANT) . For this purpose, a healthy spot welding model was first...
The Evaluation of Different Parameters on Fatigue Life of Carbon / Epoxy and Carbon / Phenolic Polymer Composite Rods under Tensile-pressure Loads
, M.Sc. Thesis Sharif University of Technology ; Hosseini Kordkheili, Ali (Supervisor)
Abstract
The aim of this dissertation is to analyze the tensile-stress fatigue of composite rods made of a combination of carbon-epoxy resin as well as carbon chopped-phenolic resin and to investigate the effect of different parameters on their fatigue life. The curing process is completely different in carbon / epoxy and carbon / phenolic composites, Carbon / Epoxy is a thermo-plastic composite, but carbon / phenolic is a thermo- set composite. Therefore, differences in the curing process, raw materials, changes in the volume percentage of resin and fibers, the effects of different loading during the production and curing process of the composite, cooling and heating rates during production can...
Influence of residual stress on fatigue life of st-37 butt-mag weldment
, Article 12th International Conference on Metal Forming, METAL FORMING 2008, Krakow, 21 September 2008 through 24 September 2008 ; Volume 79, Issue 2 , 2008 , Pages 280-287 ; 16113683 (ISSN) ; Majzoobi, G. H ; Fadaee, A ; Sharif University of Technology
Wiley-VCH Verlag
2008
Abstract
In this paper residual stresses induced by butt metal arc gas welding (MAGW), in accordance with ASTM E837, are determined by hole drilling. The results are analyzed by probabilistic methods. Also, the effect of fatigue life on relaxation of welding residual stress is investigated. The specimens are tested to measure fatigue life and crack growth rates in accordance with ASTM E466 for force controlled amplitude axial fatigue testing. © 2008 Verlag Stahleisen GmbH, Düsseldorf
Fatigue properties of machinable austempered ductile iron
, Article 16th International Metallurgical and Materials Conference, METAL 2007, 22 May 2007 through 24 May 2007 ; 2007 ; Baghersaee, N ; Varahram, N ; Hanumantha Rao, M ; Sharif University of Technology
TANGER spol. s r.o
2007
Abstract
MADI is new engineering material with very desirable properties such as higher strength at the same hardness compared to regular ductile iron, significantly better fatigue performance than regular ductile iron or austempered ductile iron, better machinability than regular austempered ductile iron and similar to as cast ductile iron. In this study,fatigue properties of Machinable Austempering Ductile was investigated using rotary -bend fatigue testing device. Chemical composition of sample was selected on the base of previous work which results in good mechanical properties and low hardness after austempering process. The results of this study,indicates that for an austempered ductile iron...
Simultaneous effects of cutting depth and tool overhang on the vibration behavior of cutting tool and high-cycle fatigue behavior of product: experimental research on the turning machine
, Article International Journal of Advanced Manufacturing Technology ; Volume 122, Issue 5-6 , 2022 , Pages 2361-2378 ; 02683768 (ISSN) ; Borisovna, K. D ; Ghorbani, S ; Reza Kashyzadeh, K ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
One of the major challenges in the manufacturing parts, especially metals, is turning with good/excellent surface quality, which has a significant effect on the fatigue strength of the industrial components. Selecting incorrect or unsuitable values of machining parameters leads to vibration instability in the cutting tool and as a result, excessive roughness is created on the product’s surface. Therefore, one of the ways to reduce the roughness factor and increase the product fatigue life is to control the relative slip and vibration between the cutting tool and the workpiece. To achieve this goal, the authors attempted to investigate the simultaneous effects of tool overhang and cutting...
Crack-based healing master curve derived from linear amplitude sweep tests: a cohesive healing indicator for asphalt binders
, Article Materials and Structures/Materiaux et Constructions ; Volume 54, Issue 4 , 2021 ; 13595997 (ISSN) ; Tabatabaee, N ; Hajj, R ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
This investigation employed an interrupted torsion fatigue test using the linear amplitude sweep procedure to assess the intrinsic self-healing potential of unaged, aged, rejuvenated, and re-aged asphalt binders. Continuous oscillatory shear strain loading at different damage levels were interrupted with a single rest period of different durations. An index based on the decrease in crack length following the rest period (Ha) has been defined to accurately reflect the occurrence of healing. The results indicate that Ha is higher at lower damage levels and for longer rest-period durations. The amount of irreversible crack growth increased with an increase in crack propagation and aging level....
Comparison between isothermal and non-isothermal fatigue behavior in a cast aluminum-silicon-magnesium alloy
, Article Strength of Materials ; Volume 47, Issue 6 , November , 2015 , Pages 840-848 ; 00392316 (ISSN) ; Winter, G ; Farrahi, G. H ; Sharif University of Technology
Springer New York LLC
2015
Abstract
In the present study, the out-of-phase thermomechanical fatigue (OP-TMF) behavior of a cast aluminum-silicon-magnesium alloy, the A356.0 alloy which has been widely used in diesel engine cylinder heads, is compared to room-temperature and high-temperature low cycle fatigue (RT-, HT-LCF) behaviors. For this purpose, strain/temperature-controlled isothermal and non-isothermal fatigue tests were performed based on realistic loading conditions in cylinder heads. Fatigue tests results showed that the plastic strain increased during cycles under constant mechanical strain amplitude, while the specimen failed. Under LCF loadings, the cyclic hardening occurred at low temperatures for the A356.0...
Effect of severe shot peening on the fatigue life of the laser-cladded Inconel 718 specimens
, Article International Journal of Advanced Manufacturing Technology ; Volume 104, Issue 5-8 , 2019 , Pages 2619-2631 ; 02683768 (ISSN) ; Farrahi, G. H ; Movahhedy, M. R
Springer London
2019
Abstract
This paper presents the influence of the severe shot peening process on the fatigue life of the laser-cladded Inconel 718 specimens which can be employed during refurbishment of components enduring high mechanical cyclic loads such as gas turbine components. In order to quantitatively evaluate the destructive effect of laser cladding on the fatigue endurance, fatigue tests are first performed on the as-received and laser-cladded specimens. Then, microstructural analysis by scanning electron microscope (SEM) is carried out to identify the root causes of the drawback of laser cladding. Moreover, by employing a comprehensive laser-cladding FE analysis considering cyclic plastic material...
Constitutive modeling of elastic-visco-plastic behaviors in aluminum alloys subjected to cyclic loadings at various strain rates
, Article Journal of Strain Analysis for Engineering Design ; Volume 50, Issue 2 , December , 2015 , Pages 103-124 ; 03093247 (ISSN) ; Azadi, M ; Farrahi, G. H ; Sharif University of Technology
SAGE Publications Ltd
2015
Abstract
In this article, simulations of the stress-strain behavior in aluminum alloys were investigated under cyclic loadings at various strain rates. Four plasticity approaches were applied to simulate cyclic behaviors. To validate obtained results, strain-controlled tensile-compressive fatigue tests were performed in the low cycle fatigue regime. Isothermal fatigue experiments were conducted at various strain rates. Thermo-mechanical fatigue experiments were carried out at different rates of cooling and heating processes. Numerical results demonstrated a good agreement with experimental data at the mid-life cycle of the material. Material constants for different models were also presented for...
A progressive multi-scale fatigue model for life prediction of laminated composites
, Article Journal of Composite Materials ; Volume 51, Issue 20 , 2017 , Pages 2949-2960 ; 00219983 (ISSN) ; Toozandehjani, H ; Soltani, Z ; Sharif University of Technology
SAGE Publications Ltd
2017
Abstract
This article presents a multi-scale progressive micro-mechanical fatigue model. The model employs fundamental equation of the kinetic theory of fracture to calculate damage parameters of both fiber and matrix during cyclic loading. In order to adapt the equation, required material coefficients of the constituents can be achieved from fatigue test results of longitudinal and transverse unidirectional composites, only. Sharing stress capacities of fiber and matrix are determined using a modified progressive micro-mechanical bridging model in the presence of damage. The damage parameters in the constituents are calculated employing two different equivalent scalars. However, during sinusoidal...
Fatigue life prediction of pre-corroded AZ31 magnesium alloy based on surface topology
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; 2021 ; 09544062 (ISSN) ; Adibnazari, S ; Sharif University of Technology
SAGE Publications Ltd
2021
Abstract
This research explored the corrosion effect of NaCl solution on the surface quality of AZ31 magnesium alloy. Cubic-shaped specimens were immersed in standard 3.5% NaCl solution for 1, 2, 3, and 4 hours. The size of corrosion pits, fatigue crack propagation area, and surface topology were characterized. Fatigue tests were carried out on pre-corroded AZ31 specimens under different stress amplitudes. The correlation between the corrosion time and the virtual crack size was obtained. The virtual crack size is a new parameter that can relate the corrosion to the fatigue life. A new model was proposed to map the surface topology on the virtual crack size of pre-corroded AZ31 magnesium alloy. The...
Fatigue life prediction of pre-corroded AZ31 magnesium alloy based on surface topology
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 236, Issue 7 , 2022 , Pages 3623-3635 ; 09544062 (ISSN) ; Adibnazari, S ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
This research explored the corrosion effect of NaCl solution on the surface quality of AZ31 magnesium alloy. Cubic-shaped specimens were immersed in standard 3.5% NaCl solution for 1, 2, 3, and 4 hours. The size of corrosion pits, fatigue crack propagation area, and surface topology were characterized. Fatigue tests were carried out on pre-corroded AZ31 specimens under different stress amplitudes. The correlation between the corrosion time and the virtual crack size was obtained. The virtual crack size is a new parameter that can relate the corrosion to the fatigue life. A new model was proposed to map the surface topology on the virtual crack size of pre-corroded AZ31 magnesium alloy. The...
Effects of conventional and severe shot peening on residual stress and fatigue strength of steel aisi 1060 and residual stress relaxation due to fatigue loading: experimental and numerical simulation
, Article Metals and Materials International ; Volume 27, Issue 8 , 2021 , Pages 2575-2591 ; 15989623 (ISSN) ; Farrahi, G. H ; Reza Kashyzadeh, K ; Unal, O ; Gugaliano, M ; Bagherifard, S ; Sharif University of Technology
Korean Institute of Metals and Materials
2021
Abstract
Abstract: This study investigates and compares the effects of different shot peening treatments including conventional and severe shot peening on microstructure, mechanical properties, fatigue behavior, and residual stress relaxation of AISI 1060 steel. Shot peening treatments were applied with two Almen intensities of 17 and 21 A and a wide ranges of coverage (100%–1500%). Various microstructural observations were carried out to analyze the evolution of microstructure. Microhardness, residual stress and surface roughness measurements and also axial fatigue test were performed. Moreover, the extent of the residual stress relaxation during cyclic loading was investigated by means of XRD...
Mechanical and electrochemical behaviors of butt-welded high temperature steel pipes
, Article Engineering Failure Analysis ; 2016 ; 13506307 (ISSN) ; Vanini, S. A. S ; Fereiduni, E ; Rokni, M. H ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
In this study, fatigue, corrosion fatigue and electrochemical behaviors of butt-welded A106-B steel pipes were investigated. These pipes were subjected to mechanical and thermal cyclic stresses due to the internal pressure fluctuations and cooling-heating cycles. Residual stress measurements were carried out for three different depths through the thickness and were correlated to the microstructural observations and microhardness measurements. Results showed that the maximum tensile residual stresses existed at the boundary of weld metal and base metal because of the contraction-expansion effects resulting from phase transformations and cooling rate differences. Fatigue fractures occurred at...
Experimental accuracy assessment of various high-cycle fatigue criteria for a critical component with a complicated geometry and multi-input random non-proportional 3D stress components
, Article Engineering Failure Analysis ; Volume 90 , 2018 , Pages 534-553 ; 13506307 (ISSN) ; Farrahi, G. H ; Shariyat, M ; Ahmadian, M. T ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In the present paper, a steering knuckle of a passenger car that serves as a highly critical component from the safety point of view, is considered to evaluate accuracy some of categories of the multiaxial fatigue criteria, through comparing their predictions with the experimental results. This component is subjected to the highest road- and steering-induced random and non-proportional loads that are exerted on several points of the component. The mechanical properties and fatigue strengths are determined experimentally and the fatigue life assessment tests are performed by the authors. Quantometric analyses and scanning electron microscope (SEM) have been employed to detect the failure...
Effectiveness of linear amplitude sweep (LAS) asphalt binder test in predicting asphalt mixtures fatigue performance
, Article Construction and Building Materials ; Volume 171 , May , 2018 , Pages 281-290 ; 09500618 (ISSN) ; Mirzaeian, D ; Moniri, A ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this research, Linear Amplitude Sweep (LAS) test was conducted on several asphalt binders modified by different percentages of gilsonite and Styrene-Butadiene-Styrene (SBS) polymer. Asphalt mixtures were also made from some of the study binders and tested for fatigue resistance using Four-point Bending Beam (FBB) fatigue test. The results showed that a strong correlation exists between LAS and FBB rankings at all the tested strain levels. Also, SHRP binder fatigue index (G∗sinδ), as a traditional binder fatigue index, was evaluated which did not show a strong correlation with either LAS or FBB tests. It was concluded that LAS test seems to be an effective binder fatigue test in predicting...
Applications of ultrasonic testing and machine learning methods to predict the static & fatigue behavior of spot-welded joints
, Article Journal of Manufacturing Processes ; Volume 52 , 2020 , Pages 26-34 ; Farrahi, G. H ; Kashyzadeh, K. R ; Chizari, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Ultrasonic Testing (UT) is one of the well-known Non-Destructive Techniques (NDT) of spot-weld inspection in the advanced industries, especially in automotive industry. However, the relationship between the UT results and strength of the spot-welded joints subjected to various loading conditions is unknown. The main purpose of this research is to present an integrated search system as a new approach for assessment of tensile strength and fatigue behavior of the spot-welded joints. To this end, Resistance Spot Weld (RSW) specimens of three-sheets were made of different types of low carbon steel. Afterward, the ultrasonic tests were carried out and the pulse-echo data of each sample were...
Effects of two- and three-dimensional graphene-based nanomaterials on the fatigue behavior of epoxy nanocomposites
, Article Materials Today Communications ; Volume 24 , September , 2020 ; Adibnazari, S ; Imam, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Epoxy resins and their derivatives, such as composites and epoxy adhesives, are widely used in various industries. However, epoxy resins have low performance against dynamic loading and crack propagation. Graphene-based nanomaterials can improve the mechanical performance of polymeric composites because of their appropriate mechanical properties and high surface area. This study aimed to investigate the effect of Two-Dimensional Graphene Oxide (2DGO) and Three-Dimensional Nitrogen-Doped Graphene (3D(N)G) nanomaterials on the fatigue behavior of epoxy resin. 2DGO was produced by the modified Hummer's method and 3D(N)G was synthesised by hydrothermal process, followed by freeze-drying....