Finite strain swelling induced bending in bilayer gels: semi-analytical and numerical approaches
MohammadReza
Bayat
PhD student, School of mechanical engineering, University of Tehran
author
Arash
Kargar estahbanati
کارشناسی ارشد، دانشکده مهندسی مکانیک، دانشگاه تهران
author
Mostafa
Baghani
نویسنده مسئول، دانشیار، دانشکده مهندسی مکانیک، دانشگاه تهران
author
text
article
2020
per
The accurate and efficient design of the bilayer sensors and actuators made of hydrogels are of crucial importance. In this work, a semi-analytical method is developed to solve the swelling induced bending of hydrogel bilayer under plane strain condition. The bilayer consists of a neutral incompressible elastomer layer attached to a hydrogel layer. The interface of two layers is assumed to be perfectly bonded. Moreover, the plotted problem is simulated using Finite Element Method (FEM) employing UHYPER subroutine in ABAQUS software. Several cases are solved to demonstrate the validity and performance of the proposed semi-analytical method. A good correspondence between the presented method and the finite element method is observed. The deformation and the stresses inside the layers are presented for various material parameters employing both the developed semi-analytical formulation as well as the finite element method. Finally, the effect of density of cross-link in hydrogel polymer network on curvature is also investigated.
Iranian Journal of Mechanical Engineering Transactions of ISME
ISME
2538-4775
22
v.
1
no.
2020
https://jmep.isme.ir/article_44843_215ece26224ca20ecef029a11f97b841.pdf
dx.doi.org/10.30506/ijmep.2020.78718.1355
Experimental and numerical investigation on performance of sandwich panels using aluminum faces and polyurethane foam core with variable density against explosive loading
Reza
Khondabi
Department of mechanical Engineering
Faculty of Engineering
Imam Hossein Comprehensive University
author
Hossein
Khodarahmi
Department of mechanical Engineering
Faculty of Engineering
Imam Hossein Comprehensive University
author
Rouhollah
Hosseini
Department of mechanical Engineering
Faculty of Engineering
Imam Hossein Comprehensive University
author
Mojtaba
Zia Shamami
Department of Mechanical Engineering
Imam Hossein Comprehensive University
author
text
article
2020
per
Sandwich panels, due to high strength to weight ratio and energy absorption properties, are widely used in various fields including aerospace, marine and automotive industries. This study has explored the blast resistance of sandwich structures with aluminum face-sheets and variable density polyurethane foam core (graded). In this article, several aluminum sandwich panels with polyurethane foam core having different densities is designed and have been tested. Using a blast shock tube facility, the effects of graded changes of core foam density and foam layers sequence with different densities on transverse deflection of back face-sheet are studied. Also using the compression test results performed on the foam, numerical simulations are performed using Autodyn software. The results show that there is a good agreement between numerical and experimental results with a maximum error of 13%. Experimental and numerical investigations indicate that deformation of back face-sheet of the sandwich panel with graded foam core, when the foam layer with higher density is placed in the blast side, is less than a single layer sandwich panel and equivalent mass. So it is better to use it as the main structure. Also, in case the foam layer with less density is placed in the blast side, the energy absorption of the panel increases and so the use of this panel is suggested as a protective structure.
Iranian Journal of Mechanical Engineering Transactions of ISME
ISME
2538-4775
22
v.
1
no.
2020
https://jmep.isme.ir/article_44844_08b04b156a468a6fdcec05f454629b19.pdf
dx.doi.org/10.30506/ijmep.2020.90606.1437
Mechanical Buckling of FG-CNT Reinforced Composite Cylindrical Panels
Raziyeh
Hashemi
Department of Civil Engineering, University of Qom, Qom
author
Mostafa
Mirzaei
Department of Mechanical Engineering, Faculty of Engineering, University of Qom, Qom
author
Mohammad Reza
Adlparvar
Department of Civil Engineering, Faculty of Engineering, University of Qom, Qom
author
text
article
2020
per
In this study, mechanical buckling of composite cylindrical panels reinforced with single walled carbon nanotubes under axial compression is investigated. Distribution of SWCNTs across the thickness of the panel is considered to be uniform or functionally graded. Mechanical Properties of the carbon nanotube reinforced cylindrical panel are obtained using micromechanical approaches such as the modified rule of mixtures and Eshelby-Mori-Tanaka approaches. The governing equations are obtained by using Hamilton’s principle based on first-order shear deformation theory and considering strain-displacement linear relation. An energy based Ritz method and Chebyshev polynomials are used to obtain the critical buckling load of composite cylindrical panels. In addition, the effect of various parameters such as boundary conditions, geometrical conditions, distribution pattern across the thickness of carbon nanotubes and their volume fraction are studied on the critical buckling load. It is shown that, FG-X pattern of SWCNTs distribution results in the maximum critical buckling load and by increasing the volume fraction of carbon nanotubes, the critical buckling load of composite cylindrical panel increases.
Iranian Journal of Mechanical Engineering Transactions of ISME
ISME
2538-4775
22
v.
1
no.
2020
https://jmep.isme.ir/article_44845_ab3bda6372723151bc2d419b4699bc31.pdf
dx.doi.org/10.30506/ijmep.2020.90739.1438
Impedance-based structural health monitoring of a Aluminium frame
Mohsen
Mohsenzadeh
Shahid Rajaee Teacher Training University
author
Seyed Reza
Hamzehloo
استادیار دانشکده مهندسی مکانیک، دانشگاه تربیت دبیر شهید رجایی، تهران
author
Ali
pourkamali anaraki
دانشیار، دانشکده مهندسی مکانیک، دانشگاه تربیت دبیر شهید رجایی، تهران
author
text
article
2020
per
The electro-mechanical impedance method identified as a suitable method for structural health monitoring and damage detection in structures, which is considered as a non-destructive inspection method. Piezoelectric smart materials are used as sensor/actuator to excite the structure and is installed on the structure, which has the task of identifying and measuring any changes in the structure. The basis of the electro-mechanical impedance method is to identify the detections due to the change in the stiffness of the structure, and it depends on geometry and properties of the materials to be studied. Detecting the defects that created on frame structure (L-shaped beam) by electro-mechanical impedance method and validation the analytical method by comparison with the experimental method is this paper’s objective. Defects are created in the groove shape before and after the bend and the real impedance spectrum of damaged frame that obtained from the experimental method at each step compared with healthy frame, and the damage index figure have been extracted. Also, the real spectrum of the impedance obtained from the experimental tests will be compared with the real spectrum of the impedance that obtained from analytic method. Comparison of the impedance spectrum and also the damage indexes from experimental tests for a healthy structures and defective structures shows compliance between the Stiffness and impedance of structure. Also the spectrum of real part of impedance obtained from the analytical method for the frame structure in the case of a cantilever boundary conditions has a correlation with the experimental tests.
Iranian Journal of Mechanical Engineering Transactions of ISME
ISME
2538-4775
22
v.
1
no.
2020
https://jmep.isme.ir/article_44846_50740de5494cd4d617d4520178e0d1f8.pdf
dx.doi.org/10.30506/ijmep.2020.90780.1442
Assessment of the amount of residual stresses in a thermal barrier coating system due to deposition process using analytical, experimental and numerical methods
Maryam
Mohammadi
University of Zanjan
author
Esmaeil
Poursaeidi
Department of Mechanical Engineering, University of Zanjan
author
text
article
2020
per
In this paper, residual thermal stresses caused by quenching of layers as well as the thermal expansion mismatch between the coating layers due to a sharp drop in temperature during the deposition process in the thermal barrier coating system is evaluated using an analytical model, experimental tests and a finite element model. Due to the inherent complexity of these coatings, the problem is solved analytically after some simplification. The residual stresses of the coated samples were measures using XRD method. In order to calculate the stress distribution in the whole system, a finite element model is proposed. In this model, the interface profile of the coating layers was extracted based on SEM images so it was considered to be resemble the real case. Also the boundary conditions were applied to this sub model in a way that it is in a good accordance with the experimental tests loading. The analytical results showed that the quenching residual stresses of the layers have a minor amount compared to the thermal mismatch stresses between the layers in the tests. The average value of the measured residual stresses is -150 MPa, which has a good agreement with the results obtained from the analytical and finite element methods.
Iranian Journal of Mechanical Engineering Transactions of ISME
ISME
2538-4775
22
v.
1
no.
2020
https://jmep.isme.ir/article_44847_2b801c0ea03637b91a5c5aa7313098c8.pdf
dx.doi.org/10.30506/ijmep.2020.90939.1443
Thermoelastic analysis of transient FGM thick cylindrical shells using first order shear deformation theory with considering the vertical transverse strains according to Mirsky- Herman assumption
Seyyed amirreza
Vaziri
Faculty of Mechanical Engineering, Ph.D. Student, ShahroodUT, shahrood,Iran.
author
Mehdi
ghannad
Faculty of Mechanical Engineering, associate professor, ShahroodUT, Shahrood,Iran
author
Mohammadreza
Gharib
Assistant Professor of Mechanical Engineering, University of Torbat Heydarieh
author
text
article
2020
per
In this article, analytical formulation of axisymmetric FGM thick-walled cylinders with power varying of mechanical and thermal properties under transient heating using first order shear deformation theory is presented. Equilibrium equations are derived from virtual work principles and energy method. Also, the transient heat transfer equation is solved by separation of variables, generalized Bessel function, and Eigenfunction method. General thermal boundary condition involving conduction and convection without heat source is considered. At the end the results of the analytical solution are compared with the finite element method, for this aim cylinder is modeled in Abaqus. The effects of time varying on stress and displacement distribution has been studied in this paper. according to results increasing time lead to increase the stress and displacement, by the way after a moment the stress and displacement are time-independent and they become constant. the boundary condition of two ends and thermal boundary condition play a significant role in results.
Iranian Journal of Mechanical Engineering Transactions of ISME
ISME
2538-4775
22
v.
1
no.
2020
https://jmep.isme.ir/article_44848_a0ca8c54105fd59ffee84ffbe3d66c87.pdf
dx.doi.org/10.30506/ijmep.2020.92301.1455
Model Predictive Controller Design for Lateral Behavior in Real Traffic Flow
Alireza
Khodayari
Department of Mechanical Engineering, Pardis Branch, Islamic Azad University
author
Ali
Ghaffari
K. N. Toosi Univ.
author
Amirreza
Mirbeigi Moghadam
KNTU
author
text
article
2020
per
In this paper a model-based predictive controller has been designed to control the lateral vehicle dynamics. Assuming that the road specifications are known, the main goal is to obtain a control input in order to drive along a desired path using a model-based predictive controller under the consideration of the vehicle dynamics constrains and road geometric specifications. Moreover, the curvature of the path is assumed to be specific and determinable. Steering wheel angle is the control input. Optimization problem of the designed controller is solved based on knowledge about vehicle constrains such as magnitude and rate of the steering wheel angle. These constraints are specified based on characteristics of actual vehicle to assure the safety of passengers when control system is active. In order to model the vehicle dynamics, bicycle model has been used with the assumption that considering range of the vehicle and road parameters the dynamics of the tires is in the linear part of their behavior. Using the model-base predictive controller, control input is obtained and applied to the vehicle in order to reduce the look-ahead vertical distance from the desired path to zero. The longitudinal velocity of the vehicle has been assumed to be constant. The robustness of the design controller has been investigated against environmental disturbances in dry and slippery roads. The comparison between the results of the presented control system and previous works shows that proposed method has a better performance and can increase safety of the vehicle and passengers.
Iranian Journal of Mechanical Engineering Transactions of ISME
ISME
2538-4775
22
v.
1
no.
2020
https://jmep.isme.ir/article_44849_91786c7a5290f9494cf74a539e119c5b.pdf
dx.doi.org/10.30506/ijmep.2020.92620.1459
Experimental Investigation of the Effect of Internal Damage on Ballistic Resistance of Layered Composites
majid
azadpour
Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
author
aazam
ghassemi
Department of mechanical engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran
author
text
article
2020
per
In this research , for the first time, the effect of important internal damages; such as debonding , internal cracks , interlayer contamination on the ballistic strength of composite layers have been investigated. In this study , undamaged and damaged samples of composite layers are made by wet lay-up method. The results of this assessment showed that the damage caused the ballistic strength of the composite material to decrease. Also , by comparing the results for three internal damages , it was showed that the highest and lowest loss of ballistic resistance is related to debonding damage and interlayer contamination damage, respectively. Also, in this research , tensile analysis of the samples showed that the tensile behavior of all samples was close enough to each other. However , the maximum and minimum effects on tensile behavior of the samples are related to the sample with crack internal and interlayer contamination.
Iranian Journal of Mechanical Engineering Transactions of ISME
ISME
2538-4775
22
v.
1
no.
2020
https://jmep.isme.ir/article_44850_b35ccf14efbf9005608e1053530ecaa5.pdf
dx.doi.org/10.30506/ijmep.2020.92993.1460
Nonlinear control and Stability of the Tractor Semi-Trailer System based on the Sliding Mode Control In Order to Jackknife Prevention
Mahdi
Abtahi
Industrial and Mechanical engineering faculty, Qazvin islamic Azad University
author
Mahdi
Saraei Sahnesaraei
Ms student
author
Farzin
Zohdi
Ms student
author
text
article
2020
per
In this paper, with applying the direct control on the fifth wheel, the dynamical behavior of the tractor semi-trailer vehicles is modified against the jackknife phenomenon. For this purpose, mathematical model of the system is derived using the Newton-Euler equations and after simulation of the open loop system, the modeling process is verified using the Sim-truck results. In order to control and the lateral stability of the vehicle system, the optimal controller based on the linear quadratic regulator is designed. Furthermore, for achieving to robust control system, the nonlinear controller on the basis of the Sliding mode control is also applied on the system. The comparison of the control system results demonstrates the proper performance in the settling time and the robustness of the sliding mode controller in the stability and improvement of the dynamical behavior in the system. On the other hand, the sliding mode control system can stabilize the system with least energy consumption according to behavior of control signals.
Iranian Journal of Mechanical Engineering Transactions of ISME
ISME
2538-4775
22
v.
1
no.
2020
https://jmep.isme.ir/article_44851_7a4044a046251b741350e3e5340519b9.pdf
dx.doi.org/10.30506/ijmep.2020.65674.1253
Task space path following for planar redundant robots using Pontryagin’s principle in optimal control
Kambiz
Ghaemi Osgouie
Mechanical Engineering Division, Caspian Faculty of Engineering, College of Engineering, University of Tehran, Rezvanshar, Iran.
author
Assal
Haghighatpars
Department of Electronics and Computer, Science and Research Branch, Islamic Azad University, Tehran, Iran.
author
Faezeh
Farivar
Department of Electronics and Computer, Science and Research Branch, Islamic Azad University, Tehran, Iran.
author
text
article
2020
per
Several actuation systems in the nature are modelled as redundant robotic arms for which various criteria, such as time, energy, or jerk, might be optimized to generate the most natural motion trajectories. The most suitable yet challenging optimization criterion is manipulator’s consumed energy. In this paper, the joint space kinematic optimization of a redundant planar robot is performed to follow a given task space path. Considering the redundancy of the robot, an initial guess is made for the joint space excessive degrees of freedom of the robot. Then applying the inverse kinematic equations and Pontryagin’s relations, the whole joint space path is calculated. In the implementation of the transversality conditions, according to the error occurred at the other end of the path, the initial guess is updated. Through a try-error process using shooting method, the optimal initial guess is converged and its corresponding joint space trajectory is also obtained. As a numerical evaluation, a sample task space desired path is considered and using the proposed method the proper joint space trajectory is obtained.
Iranian Journal of Mechanical Engineering Transactions of ISME
ISME
2538-4775
22
v.
1
no.
2020
https://jmep.isme.ir/article_44889_1306dd10328ff545f7da1dc649c4010f.pdf
dx.doi.org/10.30506/ijmep.2020.90792.1441