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Progressive bearing failure modeling of composites with double-bolted joints at mesoscale level
, Article Archive of Applied Mechanics ; Vol. 84, issue. 5 , May , 2014 , p. 657-669 ; 09391533 ; Hosseini Kordkheili, S. A ; Toozandehjani, H ; Sharif University of Technology
Abstract
Both numerical and experimental researches are carried out to study the strength of the composite double-bolted joints and the bearing damage propagation. A mesoscale level progressive damage model along with analytical formulation is used to predict the bearing failure of carbon-epoxy composite plates. This damage model is introduced as a user material subroutine in the commercial software ABAQUS, and the maximum failure load is calculated. In order to validate the numerical results, experimental tests are also conducted in which comparison between the results shows an excellent agreement. Furthermore, the effects of the bolt distances on the maximum failure load are studied. The results...
Numerical Simulation and Investigation of Different Parameters on Performance of Swellable Packers
, M.Sc. Thesis Sharif University of Technology ; Arghavani Hadi, Jamal (Supervisor) ; Asempoor, Ahmad (Co-Supervisor)
Abstract
When swellable elastomers expose to a suitable fluid, they swell by adsorption, which the result composition is called the gel. Gels have a variety of application, including drug delivery, sensors, actuators, micro-valves, and swellable packers. Swellable packers are a widely used tool in the oil and gas industry that are used for various operations such as supporting cement operations, water shut-off and well compartmentization, so appropriate knowledge about their behavior and the impact of various factors on its performance can lead to the optimal and safe designing of these devices. In this thesis, a suitable and validated potential energy function has been selected to evaluate the...
An improvement on the Brinson model for shape memory alloys with application to two-dimensional beam element
, Article Journal of Intelligent Material Systems and Structures ; Volume 25, Issue 15 , 1 October , 2014 , Pages 1905-1920 ; ISSN: 1045389X ; Arghavani, J ; Naghdabadi, R ; Sohrabpour, S ; Sharif University of Technology
Abstract
In this article, the one-dimensional phenomenological constitutive model originally proposed by Brinson for shape memory alloys is improved to predict asymmetric behavior in tension and compression. We propose an approach that decomposes stress-induced martensite volume fraction into two parts, one in tension and one in compression. Results of numerical examples show reasonable agreement with experimental data. Moreover, we implement the proposed model in a user-defined material subroutine in the nonlinear finite element software ABAQUS/Standard as a two-dimensional Euler-Bernoulli beam element. We simulate several beam problems and a shape memory alloy staple. Regarding the results, the...
A continuum constitutive model for mechanical behavior of 5052 resin epoxy containing various percentages of MWCNTs
, Article Journal of Composite Materials ; Volume 51, Issue 17 , 2017 , Pages 2423-2434 ; 00219983 (ISSN) ; Toozandehjani, H ; Ashouri Choshali, H ; Boroumand Azad, S ; Sharif University of Technology
SAGE Publications Ltd
2017
Abstract
In this article, a continuum-based constitutive model is developed to predict the mechanical behavior of 5052 resin epoxy reinforced by multiwalled carbon nanotubes (MWCNTs) based on experimentally generated data. For this purpose, MWCNTs/epoxy specimens with various percentages of functionalized and nonfunctionalized MWCNTs are prepared. The SEM graphs indicate that functionalization leads to a better bound between epoxy and MWCNTs and a higher level of dispersion. The specimens are then tested under standard ASTM D638-02 a procedure and their true plastic stress–strain curves are extracted. Investigations on experimentally generated data reveal that a wt% dependent equation which is...
A Modified JC Constitutive Equation for 5052 Aluminum with 0.3 mm Thickness Considering Loading Rate Effect at Quasi-Static Range
, M.Sc. Thesis Sharif University of Technology ; Hosseini Kordkheili, Ali (Supervisor)
Abstract
In this thesis, both experimental and numerical approaches are conducted to present a constitutive equation for 5052 aluminum diaphragms under quasi-static strain rate loadings. For this purpose the stress-strain curves at different strain rates are obtained using tensile tests. Brittle behavior during tensile tests is observed due to samples thin thicknesses. Employing Johnson-Cook constitutive equation no yields in reasonable agreement with these tensile tests results. Therefore, developing a more suitable constitutive equation for aluminum diaphragms is taken into consideration. This equation is then implemented into the commercial finite element software, ABAQUS, via a developed user...
An improved, fully symmetric, finite-strain phenomenological constitutive model for shape memory alloys
, Article Finite Elements in Analysis and Design ; Volume 47, Issue 2 , 2011 , Pages 166-174 ; 0168874X (ISSN) ; Auricchio, F ; Naghdabadi, R ; Reali, A ; Sharif University of Technology
2011
Abstract
The ever increasing number of shape memory alloy applications has motivated the development of appropriate constitutive models taking into account large rotations and moderate or finite strains. Up to now proposed finite-strain constitutive models usually contain an asymmetric tensor in the definition of the limit (yield) function. To this end, in the present work, we propose an improved alternative constitutive model in which all quantities are symmetric. To conserve the volume during inelastic deformation, an exponential mapping is used to arrive at the time-discrete form of the evolution equation. Such a symmetric model simplifies the constitutive relations and as a result of less...
On the robustness and efficiency of integration algorithms for a 3D finite strain phenomenological SMA constitutive model
, Article International Journal for Numerical Methods in Engineering ; Volume 85, Issue 1 , July , 2011 , Pages 107-134 ; 00295981 (ISSN) ; Auricchio, F ; Naghdabadi, R ; Reali, A ; Sharif University of Technology
2011
Abstract
Most devices based on shape memory alloys experience large rotations and moderate or finite strains. This motivates the development of finite-strain constitutive models together with the appropriate computational counterparts. To this end, in the present paper a three-dimensional finite-strain phenomenological constitutive model is investigated and a robust and efficient integration algorithm is proposed. Properly defining the variables, extensively used regularization schemes are avoided and a nucleation-completion criterion is defined. Moreover, introducing a logarithmic mapping, a new form of time-discrete equations is proposed. The solution algorithm as well as a suitable initial guess...
Implementation of microplane model into three-dimensional beam element for shape memory alloys
, Article International Journal of Applied Mechanics ; Volume 7, Issue 6 , December , 2015 ; 17588251 (ISSN) ; Arghavani, J ; Naghdabadi, R ; Sohrabpour, S ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2015
Abstract
In this study, a three-dimensional (3D) beam element based on Timoshenko beam theory is introduced for shape memory alloys (SMAs). Employing the microplane approach, we use a 3D SMA constitutive model extended from a 1D model proposed by Brinson. The SMA model is implemented into a user-defined subroutine (UMAT) in the nonlinear finite element software ABAQUS/Standard. Results of numerical examples show reasonable agreement with experimental data in proportional and non-proportional loadings. Furthermore, several applications (staple, spring, structure) are simulated and the results are compared with those of continuum elements. According to the results, the 3D SMA beam element can be used...
Numerical study on the effects of main BCC rolling texture components on the formability of sheet metals
, Article International Journal of Advanced Manufacturing Technology ; Volume 80, Issue 1-4 , March , 2015 , Pages 245-253 ; 02683768 (ISSN) ; Assempour, A ; Sharif University of Technology
Springer-Verlag London Ltd
2015
Abstract
Crystallographic texture considerably affects the formability of crystalline materials. In this paper, the effects of BCC ideal rolling fibers—including α, ε, η, γ, and ξ fibers—on the sheet formability are numerically studied. The simulations are based on the numerical procedure developed by the authors in [1] in which a rate dependent crystal plasticity model along with the power law hardening are employed in a user material subroutine to model the behavior of crystalline materials. In order to determine FLD—in a M-K type approach—second-order derivative of sheet thickness variations with respect to time is used as necking criterion. The calculated FLDs of the fibers are compared with each...
An efficient, non-regularized solution algorithm for a finite strain shape memory alloy constitutive model
, Article ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, ESDA2010, 12 July 2010 through 14 July 2010, Istanbul ; Volume 4 , 2010 , Pages 131-138 ; 9780791849187 (ISBN) ; Auricchio, F ; Naghdabadi, R ; Reali, A ; Sohrabpour, S ; Sharif University of Technology
2010
Abstract
In this paper we investigate a three-dimensional finite-strain phenomenological constitutive model and propose an efficient solution algorithm by properly defining the variables and by avoiding extensively-used regularization schemes which increase the solution time. We define a nucleation-completion criterion and modify the regularized solution algorithm. Implementation of the proposed integration algorithm within a user-defined subroutine UMAT in the commercial nonlinear finite element software ABAQUS has made possible the solution of boundary value problems. The obtained results show the efficiency of the proposed solution algorithm and confirm the improved efficiency (in terms of...
Coupling behavior of the pH/temperature sensitive hydrogels for the inhomogeneous and homogeneous swelling
, Article Smart Materials and Structures ; Volume 25, Issue 8 , 2016 ; 09641726 (ISSN) ; Baghani, M ; Naghdabadi, R ; Sohrabpour, S ; Sharif University of Technology
Institute of Physics Publishing
2016
Abstract
In this work, a model is developed to continuously predict homogeneous and inhomogeneous swelling behavior of pH/temperature sensitive PNIPAM hydrogels. Employing the model, homogeneous swelling of the pH/temperature sensitive hydrogel is investigated for free and biaxial constrained swelling cases. Comparing the model results with the experimental data available in the literature, the validity of the model is confirmed. The model is then employed to investigate inhomogeneous swelling of a spherical shell on a hard core both analytically and numerically for pH or temperature variations. In this regard, numerical tools are developed via preparing a user defined subroutine in ABAQUS software....
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...
A particular criterion for progressive failure analysis of carbon/phenolic tape-wounded conic shells
, Article International Journal of Damage Mechanics ; Volume 30, Issue 8 , 2021 , Pages 1238-1260 ; 10567895 (ISSN) ; Karimian, M ; Jafari, H. R ; Sharif University of Technology
SAGE Publications Ltd
2021
Abstract
Conic shell structures are widely used in aerospace industries. In the literature various models have been proposed to failure analysis of composite materials. Clearly, each model has a favorable range of applications. In this paper tensile, compressive, shear and thermal expansion properties of tape-wounded Carbon/Phenolic composites are firstly measured at various temperatures in range 23–200°C. The captured properties are then taken into account to progressive failure analysis of a conic Carbon/Phenolic structure under internal pressure and thermal loadings. For this end, a particular failure criterion is proposed to predict failure in the composite structures with a reasonable margin of...
Life prediction of wind turbine blades using multi-scale damage model
, Article Journal of Reinforced Plastics and Composites ; Volume 40, Issue 17-18 , 2021 , Pages 644-653 ; 07316844 (ISSN) ; Hemati, M ; Torabnia, S ; Sharif University of Technology
SAGE Publications Ltd
2021
Abstract
Wind turbine blade life prediction is the most important parameter to estimate the power generation cost. Due to the price and importance of wind blade, many experimental and theoretical methods were developed to estimate damages and blade life. A novel multiaxial fatigue damage model is suggested for the life prediction of a wind turbine blade. Fatigue reduction of fiber and interfiber characteristics are separately treated and simulated in this research. Damage behavior is considered in lamina level and then extended to laminate; hence, this model can be used for multidirectional laminated composites. The procedure of fatigue-induced degradation is implemented in an ABAQUS user material...
Life prediction of wind turbine blades using multi-scale damage model
, Article Journal of Reinforced Plastics and Composites ; Volume 40, Issue 17-18 , 2021 , Pages 644-653 ; 07316844 (ISSN) ; Hemati, M ; Torabnia, S ; Sharif University of Technology
SAGE Publications Ltd
2021
Abstract
Wind turbine blade life prediction is the most important parameter to estimate the power generation cost. Due to the price and importance of wind blade, many experimental and theoretical methods were developed to estimate damages and blade life. A novel multiaxial fatigue damage model is suggested for the life prediction of a wind turbine blade. Fatigue reduction of fiber and interfiber characteristics are separately treated and simulated in this research. Damage behavior is considered in lamina level and then extended to laminate; hence, this model can be used for multidirectional laminated composites. The procedure of fatigue-induced degradation is implemented in an ABAQUS user material...
Coupled continuum damage mechanics and crystal plasticity model and its application in damage evolution in polycrystalline aggregates
, Article Engineering with Computers ; 2021 ; 01770667 (ISSN) ; Assempour, A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
In the present study, damage initiation and growth in a polycrystalline aggregate are investigated. In this regard, an anisotropic continuum damage mechanics coupled with rate-dependent crystal plasticity theory is employed. Using a thermodynamically consistent procedure, a finite deformation formulation is derived. For this purpose, the damage tensor is incorporated in the crystal plasticity formulation for a cubic single crystal. The damage evolution is considered to be dependent on the history of damage, equivalent plastic strain, stress triaxiality, and Lode parameters. This material model is implemented in the commercial finite-element code Abaqus/Standard by developing a user material...
Mechanical response of single and double-helix SMA wire ropes
, Article Mechanics of Advanced Materials and Structures ; Volume 29, Issue 26 , 2022 , Pages 5393-5406 ; 15376494 (ISSN) ; Arghavani, J ; Choi, E ; Ostadrahimi, A ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
In this paper, based on three-dimensional phenomenological model and using a user-defined material subroutine mechanical behavior of shape memory alloy (SMA) wire ropes (or cables) and their components have been studied through implicit solution method in Abaqus software. Material parameters have been extracted using available experimental data and numerical simulations. Due to the convoluted geometry and interwire contact status within a cable, a finite element analysis is firstly performed for a 1 × 37 steel wire rope to validate modeling and mechanical interactions of a wire rope. Afterwards, superelastic and shape memory effect cables with different constructions (7 × 7 and 1 × 27) are...
Experimental and Numerical Study of Sheet Metals Formability based on Crystal Plasticity and Presentation of High Formability Fibers
, Ph.D. Dissertation Sharif University of Technology ; Assempour, Ahmad (Supervisor)
Abstract
In the classical theories of plasticity, plastic deformation of material is modeled with a macro- scopic viewpoint and without considering the existing physical mechanisms at the crystal scale. However, plastic deformation stems from slip phenomena and evolution of crystalline structure. Furthermore the effects of initial texture of material on its mechanical properties, like formability, and also texture evolution of material can only be calculated by considering these physical mecha- nisms.The main purpose of this thesis is to predict forming limit diagrams of sheet metals based on crystal plasticity approach by considering the effect of initial material texture and presentation of...
A rate-dependent constitutive equation for 5052 aluminum diaphragms
, Article Materials and Design ; Vol. 60, Issue 1 , 2014 , pp. 13-20 ; ISSN: 02613069 ; Ashrafian, M. M ; Toozandehjani, H ; Sharif University of Technology
Abstract
In this article, both experimental and numerical approaches are conducted to present a constitutive equation for 5052 aluminum diaphragms under quasi-static strain rate loadings. For this purpose the stress-strain curves at different strain rates are obtained using tensile tests. Brittle behavior during tensile tests is observed due to samples thin thicknesses. Employing Johnson-Cook constitutive equation no yields in reasonable agreement with these tensile tests results. Therefore, developing a more suitable constitutive equation for aluminum diaphragms is taken into consideration. This equation is then implemented into the commercial finite element software, ABAQUS, via a developed user...
Development of a stress-mode sensitive viscoelastic constitutive relationship for asphalt concrete: experimental and numerical modeling
, Article Mechanics of Time-Dependent Materials ; 2016 , Pages 1-35 ; 13852000 (ISSN) ; Tabatabaee, N ; Jahanbakhsh, H ; Jahangiri, B ; Sharif University of Technology
Springer Netherlands
Abstract
Asphalt binder is responsible for the thermo-viscoelastic mechanical behavior of asphalt concrete. Upon application of pure compressive stress to an asphalt concrete specimen, the stress is transferred by mechanisms such as aggregate interlock and the adhesion/cohesion properties of asphalt mastic. In the pure tensile stress mode, aggregate interlock plays a limited role in stress transfer, and the mastic phase plays the dominant role through its adhesive/cohesive and viscoelastic properties. Under actual combined loading patterns, any coordinate direction may experience different stress modes; therefore, the mechanical behavior is not the same in the different directions and the asphalt...