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Kamal Jahani

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Shiraz Branch, Islamic Azad University

Journal of Space Science, Technology and Applications

State University of Moldova

Hamid Eghbalpour

Memorial University of Newfoundland

Islamic Azad University, Semnan Branch

mostafa pirmoradian

Mohammad mahdi Emamjomeh

Qazvin university of medical science

Scientific Journal of Aerospace Mechanics

Imam Hossein University

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Papers by Kamal Jahani

Energy Harvesting Investigation from Unimorph Trapezoidal Beam Vibrations Using Distributed Parameters Method

In recent years, the need for low power electronic circuits like sensors and wireless systems has... more In recent years, the need for low power electronic circuits like sensors and wireless systems has been considered by many researchers. Excessive weight, limited lifetime of the batteries and also t h e p r o b l em o f r e p la c i n g t h em , a r e t h e m a i n r e a s on s f o r h a r v e s t i n g en e r g y f r o m am bi en t vibrations. Among the various sources of environmental energy, mechanical vibrations have gained in popularity due to their availability. Between the different methods of ambient vibration energy harvesting, piezoelectric method, is one of the good ways to harvest energy due to the favorable effects of electromechanical coupling. The most common means of harvesting energy from vibrations is a cantilevered beam with one or more piezoelectric layers. In the present paper, electrical energy harvesting from Euler-Bernoulli trapezoidal cantilevered unimorph beam with base excitation using distributed parameter method has been considered. First, equations of motion are analytically obtained and then using Assumed modes method(for rectangular beam), system's natural frequencies are calculated and output voltage, current and power diagrams are p res en ted. For verifyin g resu lts , p res en ted voltag e, cu rren t and p ower ou tp u t d iag ram s for trapezoidal configuration close to rectangular configuration, the results of which are published in references, will be compared. Then, functional parameters for trapezoidal energy harvester with resistance value changes for energy consumer have been analyzed.

Determining the Compressive Strength of Green Sand Moulds with Different Moisture Contents, Using Artificial Neural Networks

Investigating the influence of the viscoelastic material as a heart muscle simulator on the powering leadless pacemaker from heartbeats by using a piezoelectric beam

Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

This paper studies experimentally and analytically the influence of the viscoelastic cardiac musc... more This paper studies experimentally and analytically the influence of the viscoelastic cardiac muscle on the energy harvesting from heartbeats for powering the leadless pacemakers by using a piezoelectric beam. An appropriate representative gel-type viscoelastic material that mimics the heart tissue is used in the tests. The piezoelectric beam coupled with a gel-type material is analytically modeled, and experimentally tested. By considering a combination of the translational standard linear solid model and a rotational spring component for the gel-type material, the analytical model of the coupled system is developed utilizing the generalized Hamilton’s principle. The system is attached on top of a shaker and excited harmonically, and the time history of output voltage and accelerations are measured. The analytical model is verified by experimental results for the tip displacement, voltage, generated power, phase-portraits histories, and voltage FRF with harmonic base excitations. Tr...

Experimental Study of Optimum Piezoelectric Energy Harvester Circuit under Various Excitations

Proceedings of the 5th International Conference on Mechatronics and Control Engineering - ICMCE '16

Energy harvesting from environment vibrations by piezoelectric cantilevers is an attractive field... more Energy harvesting from environment vibrations by piezoelectric cantilevers is an attractive field for investigation because of piezoelectric material's inherent mechanical-electrical properties. In this paper, electrical and mechanical characteristics of piezoelectric cantilever are investigated for optimum energy harvesting, experimentally, which this cantilever is excited under harmonic, random and impulse excitations. Consequently, piezoelectric energy harvester is simulated as an equivalent electrical circuit. For this purpose, effect of external load resistance and excitation frequency on the output voltage is studied under harmonic excitation firstly. Furthermore, the effect of load resistances on natural frequency of piezoelectric cantilever is investigated while piezoelectric beam is under random excitation. Furthermore, variation of equivalent viscose damping ratio (ζ) of piezoelectric cantilever due to changes in external load resistance is studied by applying impulse excitation. Finally, the electrical properties of piezoelectric cantilever such as internal load resistance and capacity are acquired experimentally and the effect of load resistance on optimal energy harvesting is considered. Verifying the experimental harmonic and random excitations results in open circuit mode are conducted by finite element modeling in ABAQUS software.

Structural dynamics of offshore Wind Turbines: A review

Ocean Engineering, 2022

Studying effects of joint characteristics on the performance of a cantilever beam shaped piezoelectric energy harvester through joint identification

Journal of Intelligent Material Systems and Structures, 2021

In energy harvesting systems, specifications of the generated electrical energy depend on the str... more In energy harvesting systems, specifications of the generated electrical energy depend on the structure’s dynamics. This dependence can be used to identify the system’s joint characteristics. To this end, an innovative frequency-response-function (FRF) based identification method is presented. The investigated system is a cantilever beam shaped structure with an embedded bimorph piezoelectric bender, connected to a base via bolted joint as a depiction for wing of a UAV connected to fuselage. The implemented FRF is ratio of the piezoelectric output voltage to the base input displacement. The joint identification procedure consists of analytical modeling of the system with joint, experimental testing of the system and a real-coded Genetic Algorithm (GA) method. The joint is modeled as a combination of longitudinal and torsional springs, whose stiffnesses are obtained using the GA method. The obtained results indicate that the analytical model has good correlation with the experimental...

Energy Equipment and Systems Development of a laboratory system to investigate and store electrical energy from the vibrations of a piezoelectric beam

Energy harvesting from surrounding environment has been attractive for many researchers in recent... more Energy harvesting from surrounding environment has been attractive for many researchers in recent years. Therefore, developing appropriate test apparatus to study energy harvesting mechanisms and their performance is of paramount importance. Due to their electromechanical characteristics, piezoelectric materials are used for harvesting energy from environmental vibrations. For optimum utilization of this system in harvesting and storing energy, the studies need to consider the environmental conditions. In this work, the electromechanical system is developed with the aim of conducting tests on piezoelectric materials. It is an integrated system which is developed and built after considering the limitations and sensitivity of piezoelectric material. In this research, the simple piezoelectric beam is also tested. Evaluation results via this system are analysed using Abaqus. The error value in receiving output voltage is 6% because an ideal open circuit state is considered by this softw...

Effects Of Duct Geometry, Thickness And Types Of Liners On Transmission Loss For Absorptive Silencers

Sound attenuation in absorptive silencers has been analyzed in this paper. The structure of such ... more Sound attenuation in absorptive silencers has been analyzed in this paper. The structure of such devices is as follows. When the rigid duct of an expansion chamber has been lined by a packed absorptive material under a perforated membrane, incident sound waves will be dissipated by the absorptive liners. This kind of silencer, usually are applicable for medium to high frequency ranges. Several conditions for different absorptive materials, variety in their thicknesses, and different shapes of the expansion chambers have been studied in this paper. Also, graphs of sound attenuation have been compared between empty expansion chamber and duct of silencer with applying liner. Plane waves have been assumed in inlet and outlet regions of the silencer. Presented results that have been achieved by applying finite element method (FEM), have shown the dependence of the sound attenuation spectrum to flow resistivity and the thicknesses of the absorptive materials, and geometries of the cross s...

Identification of Dynamic Characteristics of Electrorheological Dampers Using a Combination of Least Squares and Radial Basis Function Neural Networks Techniques

Volume 7B: Dynamics, Vibration, and Control, 2021

Dynamic characteristics of electrorheological dampers are identified using a procedure that inclu... more Dynamic characteristics of electrorheological dampers are identified using a procedure that includes dynamic testing, modelling, and a combination of least squares and radial basis function neural networks techniques. A two-step computationally efficient and experimentally affordable approach is chosen to achieve this objective. In the first step, the response of the damper at a certain number of applied command voltages to harmonic excitation is determined and, using the least squares technique, the corresponding damper parameters are identified based on the Bingham viscoplastic model. Since the number of experiments is limited to discrete values of voltage, in the second step the radial basis function neural networks technique is implemented to identify the parameters of the model for any value of the command voltage in the experimentally investigated range. Comparison of the predicted responses of the investigated damper with the corresponding experimental results from the first ...

Application of Computer Aided Engineering Tools in Performance Prediction and Fault Detection of Mechanical Equipment of Mining Process Line

World Academy of Science, Engineering and Technology, International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering, 2016

Nowadays, to decrease the number of downtimes in the industries such as metal mining, petroleum a... more Nowadays, to decrease the number of downtimes in the industries such as metal mining, petroleum and chemical industries, predictive maintenance is crucial. In order to have efficient predictive maintenance, knowing the performance of critical equipment of production line such as pumps and hydro-cyclones under variable operating parameters, selecting best indicators of this equipment health situations, best locations for instrumentation, and also measuring of these indicators are very important. In this paper, computer aided engineering (CAE) tools are implemented to study some important elements of copper process line, namely slurry pumps and cyclone to predict the performance of these components under different working conditions. These modeling and simulations can be used in predicting, for example, the damage tolerance of the main shaft of the slurry pump or wear rate and location of cyclone wall or pump case and impeller. Also, the simulations can suggest best-measuring paramete...

Predicting the shock isolation behavior of a hydraulic engine mount by 3D finite element modeling of fluid-structure-interaction

هب عاجرا يارب دییامن هدافتسا لیذ ترابع زا هلاقم نیا : Please cite this article using: K. Jahani, ... more هب عاجرا يارب دییامن هدافتسا لیذ ترابع زا هلاقم نیا : Please cite this article using: K. Jahani, M. Dehnad, Predicting the shock isolation behavior of a hydraulic engine mount by 3D inite element modeling of luid-structure-interaction, Modares Mechanical Engineering, Vol. 14, No. 4, pp. 122-128, 2014 (In Persian) شیپ ینیب لدم اب كوش کیرحت ندرک هلوزیا رد یکیلوردیه روتوم هتسد کی راتفر يزاس هس دودحم ازجا رب يدعب مه هزاس شنک لایس

Predictingtheshockisolationbehaviorofahydraulicenginemountby3D finite element modeling of fluid-structure-interaction

هب عاجرا يارب دییامن هدافتسا لیذ ترابع زا هلاقم نیا : Please cite this article using: K. Jahani, ... more هب عاجرا يارب دییامن هدافتسا لیذ ترابع زا هلاقم نیا : Please cite this article using: K. Jahani, M. Dehnad, Predicting the shock isolation behavior of a hydraulic engine mount by 3D inite element modeling of luid-structure-interaction, Modares Mechanical Engineering, Vol. 14, No. 4, pp. 122-128, 2014 (In Persian) شیپ ینیب لدم اب كوش کیرحت ندرک هلوزیا رد یکیلوردیه روتوم هتسد کی راتفر يزاس هس دودحم ازجا رب يدعب مه هزاس شنک لایس

Hybrid method for studying the effect of the material change on the blade vibration behavior

To increase the production efficiency of a typical turbine blade, it is necessary to change its m... more To increase the production efficiency of a typical turbine blade, it is necessary to change its material and hence its production technology. In this respect and in order to make sure that newmaterial will not bring about the blade resonant vibrations, the common practice is to use the Campbell diagram approach. This approach only indicates the potential dangers for blade forced vibration. The purpose of this paper is to demonstrate the efficiency of a proposed hybrid procedure for the development of a reliable Campbell diagram, using an updated finite elementmodel and a simplified test setup.

Identification of Parameters of Spencer Model for a Double-Ended Magnetorheological Damper with Different Spherical Iron Carbonyl Powder Sizes

Development of a laboratory system to investigate and store electrical energy from the vibrations of a piezoelectric beam

Environmental Engineering Science, 2016

Energy harvesting from surrounding environment has been attractive for many researchers in recent... more Energy harvesting from surrounding environment has been attractive for many researchers in recent years. Therefore, developing appropriate test apparatus to study energy harvesting mechanisms and their performance is of paramount importance. Due to their electromechanical characteristics, piezoelectric materials are used for harvesting energy from environmental vibrations. For optimum utilization of this system in harvesting and storing energy, the studies need to consider the environmental conditions. In this work, the electromechanical system is developed with the aim of conducting tests on piezoelectric materials. It is an integrated system which is developed and built after considering the limitations and sensitivity of piezoelectric material. In this research, the simple piezoelectric beam is also tested. Evaluation results via this system are analysed using Abaqus. The error value in receiving output voltage is 6% because an ideal open circuit state is considered by this softw...

Experimental Study of the Effects of Iron Particles Size on Damping Force and Energy Dissipation of a Double-Ended Magnetorheological Damper

Cold spray deformation and deposition of blended feedstock powders not necessarily obey the rule of mixture

Surface and Coatings Technology, 2021

Abstract Cold spray additive manufacturing has the potential to be used in repair and manufacturi... more Abstract Cold spray additive manufacturing has the potential to be used in repair and manufacturing of a wide variety of parts and coatings including composite coatings. Understanding materials' fundamental behaviour during deposition is essential for the process development which was not addressed enough for mixed powders. One objective of this study is to explore the process-structure relation of mixed Ni-Ti powders in cold spray to provide a methodology to achieve a coating with the composition of interest. Single/multi-particle impact experiments and FEM modelling were employed to investigate the particle deformation and microstructure evolution using SEM, EBSD and EDS. The sprays of mixed powders were performed using a wide process parameter window and the deposition characteristics and composition variation as a function of process parameters were explored. The experiments and modelling showed that splats in dissimilar multi-particle impacts experience more deformation than those of similar materials, which in microstructural scale translates to variation of deformation mechanism from single-component coatings. This results in higher degree of grain refinement, specifically for Ti in the composite coating with an average grain size of 500 nm. Experiments showed that the DE of mixed powder deviates from the rule of mixture, which means the critical velocity of Ni-Ti powder is different from the single-component Ni and Ti coatings due to material interactions. Findings showed there is a process parameter criteria for which relative DEs of components, and thereby composition of composite coatings, remain at almost constant ratios. η (impact velocity/critical velocity ratio) is used as a measure to predict qualitative composition variation as a function of spraying parameters and powder characteristics.

Identifying the parameters of viscoelastic model for a gel-type material as representative of cardiac muscle in dynamic tests

Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 2021

In this paper, mechanical parameters of a calf heart muscle are identified and a gel-type materia... more In this paper, mechanical parameters of a calf heart muscle are identified and a gel-type material as the representative of the cardiac muscle in dynamic tests is introduced. The motivation of this study is to introduce a replacement material of the heart muscle to use in experimental studies of the leadless pacemaker. A particular test setup is developed to capture the experimental data based on the stress relaxation test method where its outputs are time histories of the force and displacement. The standard linear solid model is used for mathematical modeling of the heart muscle sample and a gel-type material specimen namely α-gel. Five tests with different strain history [Formula: see text] are performed by regarding and disregarding the influence of the initial ramp of the loading. The mechanical parameters of the standard linear solid model were identified with precise curve fitting. Consideration of the initial ramp significantly influences the consequences and they are so clo...

Dynamic microstructure evolution in cold sprayed Ni Ti composite coatings

Surface and Coatings Technology, 2021

Abstract The severe plastic deformation inherent to cold spray provides a unique opportunity to s... more Abstract The severe plastic deformation inherent to cold spray provides a unique opportunity to study dynamic microstructure evolution under extremely high strain rates, not achievable in conventional laboratory experiments. In this study, the correlation between dynamic deformation and microstructure evolution is investigated for a heterogeneous system, using cold spray of blended Ni Ti powder mixtures. EBSD analyses of the Ni and Ti particles show different degrees of dynamic recrystallization (DRX) especially at particle boundaries, which are attributed to different materials properties and dissimilar materials interaction. A heterogeneous structure of Ni Ti composite was achieved with Ni particle being embedded in an ultra-fine grain Ti matrix with an average grain size of 500 nm. Results show hierarchical structures including twins with a thickness of about 500 nm, micro-bands and low angle boundaries, which are associated with a grain subdivision mechanism through continuous dynamic recrystallization (CDRX). The results also demonstrate a drastically different response of Ti and Ni to the same loading conditions, hence provide an insight to the role of intrinsic material properties in DRX at extremely high strain rates.

Experimental and numerical study on the performance of printed alginate/hyaluronic acid/halloysite nanotube/polyvinylidene fluoride bio-scaffolds

Journal of Biomechanics, 2020

 The comparative experiments between the MPVTW and EPVTW are carried out.  Simulation models fo... more

Energy Harvesting Investigation from Unimorph Trapezoidal Beam Vibrations Using Distributed Parameters Method

In recent years, the need for low power electronic circuits like sensors and wireless systems has... more In recent years, the need for low power electronic circuits like sensors and wireless systems has been considered by many researchers. Excessive weight, limited lifetime of the batteries and also t h e p r o b l em o f r e p la c i n g t h em , a r e t h e m a i n r e a s on s f o r h a r v e s t i n g en e r g y f r o m am bi en t vibrations. Among the various sources of environmental energy, mechanical vibrations have gained in popularity due to their availability. Between the different methods of ambient vibration energy harvesting, piezoelectric method, is one of the good ways to harvest energy due to the favorable effects of electromechanical coupling. The most common means of harvesting energy from vibrations is a cantilevered beam with one or more piezoelectric layers. In the present paper, electrical energy harvesting from Euler-Bernoulli trapezoidal cantilevered unimorph beam with base excitation using distributed parameter method has been considered. First, equations of motion are analytically obtained and then using Assumed modes method(for rectangular beam), system's natural frequencies are calculated and output voltage, current and power diagrams are p res en ted. For verifyin g resu lts , p res en ted voltag e, cu rren t and p ower ou tp u t d iag ram s for trapezoidal configuration close to rectangular configuration, the results of which are published in references, will be compared. Then, functional parameters for trapezoidal energy harvester with resistance value changes for energy consumer have been analyzed.

Determining the Compressive Strength of Green Sand Moulds with Different Moisture Contents, Using Artificial Neural Networks

Investigating the influence of the viscoelastic material as a heart muscle simulator on the powering leadless pacemaker from heartbeats by using a piezoelectric beam

Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

This paper studies experimentally and analytically the influence of the viscoelastic cardiac musc... more This paper studies experimentally and analytically the influence of the viscoelastic cardiac muscle on the energy harvesting from heartbeats for powering the leadless pacemakers by using a piezoelectric beam. An appropriate representative gel-type viscoelastic material that mimics the heart tissue is used in the tests. The piezoelectric beam coupled with a gel-type material is analytically modeled, and experimentally tested. By considering a combination of the translational standard linear solid model and a rotational spring component for the gel-type material, the analytical model of the coupled system is developed utilizing the generalized Hamilton’s principle. The system is attached on top of a shaker and excited harmonically, and the time history of output voltage and accelerations are measured. The analytical model is verified by experimental results for the tip displacement, voltage, generated power, phase-portraits histories, and voltage FRF with harmonic base excitations. Tr...

Experimental Study of Optimum Piezoelectric Energy Harvester Circuit under Various Excitations

Proceedings of the 5th International Conference on Mechatronics and Control Engineering - ICMCE '16

Energy harvesting from environment vibrations by piezoelectric cantilevers is an attractive field... more Energy harvesting from environment vibrations by piezoelectric cantilevers is an attractive field for investigation because of piezoelectric material's inherent mechanical-electrical properties. In this paper, electrical and mechanical characteristics of piezoelectric cantilever are investigated for optimum energy harvesting, experimentally, which this cantilever is excited under harmonic, random and impulse excitations. Consequently, piezoelectric energy harvester is simulated as an equivalent electrical circuit. For this purpose, effect of external load resistance and excitation frequency on the output voltage is studied under harmonic excitation firstly. Furthermore, the effect of load resistances on natural frequency of piezoelectric cantilever is investigated while piezoelectric beam is under random excitation. Furthermore, variation of equivalent viscose damping ratio (ζ) of piezoelectric cantilever due to changes in external load resistance is studied by applying impulse excitation. Finally, the electrical properties of piezoelectric cantilever such as internal load resistance and capacity are acquired experimentally and the effect of load resistance on optimal energy harvesting is considered. Verifying the experimental harmonic and random excitations results in open circuit mode are conducted by finite element modeling in ABAQUS software.

Structural dynamics of offshore Wind Turbines: A review

Ocean Engineering, 2022

Studying effects of joint characteristics on the performance of a cantilever beam shaped piezoelectric energy harvester through joint identification

Journal of Intelligent Material Systems and Structures, 2021

In energy harvesting systems, specifications of the generated electrical energy depend on the str... more In energy harvesting systems, specifications of the generated electrical energy depend on the structure’s dynamics. This dependence can be used to identify the system’s joint characteristics. To this end, an innovative frequency-response-function (FRF) based identification method is presented. The investigated system is a cantilever beam shaped structure with an embedded bimorph piezoelectric bender, connected to a base via bolted joint as a depiction for wing of a UAV connected to fuselage. The implemented FRF is ratio of the piezoelectric output voltage to the base input displacement. The joint identification procedure consists of analytical modeling of the system with joint, experimental testing of the system and a real-coded Genetic Algorithm (GA) method. The joint is modeled as a combination of longitudinal and torsional springs, whose stiffnesses are obtained using the GA method. The obtained results indicate that the analytical model has good correlation with the experimental...

Energy Equipment and Systems Development of a laboratory system to investigate and store electrical energy from the vibrations of a piezoelectric beam

Energy harvesting from surrounding environment has been attractive for many researchers in recent... more Energy harvesting from surrounding environment has been attractive for many researchers in recent years. Therefore, developing appropriate test apparatus to study energy harvesting mechanisms and their performance is of paramount importance. Due to their electromechanical characteristics, piezoelectric materials are used for harvesting energy from environmental vibrations. For optimum utilization of this system in harvesting and storing energy, the studies need to consider the environmental conditions. In this work, the electromechanical system is developed with the aim of conducting tests on piezoelectric materials. It is an integrated system which is developed and built after considering the limitations and sensitivity of piezoelectric material. In this research, the simple piezoelectric beam is also tested. Evaluation results via this system are analysed using Abaqus. The error value in receiving output voltage is 6% because an ideal open circuit state is considered by this softw...

Effects Of Duct Geometry, Thickness And Types Of Liners On Transmission Loss For Absorptive Silencers

Sound attenuation in absorptive silencers has been analyzed in this paper. The structure of such ... more Sound attenuation in absorptive silencers has been analyzed in this paper. The structure of such devices is as follows. When the rigid duct of an expansion chamber has been lined by a packed absorptive material under a perforated membrane, incident sound waves will be dissipated by the absorptive liners. This kind of silencer, usually are applicable for medium to high frequency ranges. Several conditions for different absorptive materials, variety in their thicknesses, and different shapes of the expansion chambers have been studied in this paper. Also, graphs of sound attenuation have been compared between empty expansion chamber and duct of silencer with applying liner. Plane waves have been assumed in inlet and outlet regions of the silencer. Presented results that have been achieved by applying finite element method (FEM), have shown the dependence of the sound attenuation spectrum to flow resistivity and the thicknesses of the absorptive materials, and geometries of the cross s...

Identification of Dynamic Characteristics of Electrorheological Dampers Using a Combination of Least Squares and Radial Basis Function Neural Networks Techniques

Volume 7B: Dynamics, Vibration, and Control, 2021

Dynamic characteristics of electrorheological dampers are identified using a procedure that inclu... more Dynamic characteristics of electrorheological dampers are identified using a procedure that includes dynamic testing, modelling, and a combination of least squares and radial basis function neural networks techniques. A two-step computationally efficient and experimentally affordable approach is chosen to achieve this objective. In the first step, the response of the damper at a certain number of applied command voltages to harmonic excitation is determined and, using the least squares technique, the corresponding damper parameters are identified based on the Bingham viscoplastic model. Since the number of experiments is limited to discrete values of voltage, in the second step the radial basis function neural networks technique is implemented to identify the parameters of the model for any value of the command voltage in the experimentally investigated range. Comparison of the predicted responses of the investigated damper with the corresponding experimental results from the first ...

Application of Computer Aided Engineering Tools in Performance Prediction and Fault Detection of Mechanical Equipment of Mining Process Line

World Academy of Science, Engineering and Technology, International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering, 2016

Nowadays, to decrease the number of downtimes in the industries such as metal mining, petroleum a... more Nowadays, to decrease the number of downtimes in the industries such as metal mining, petroleum and chemical industries, predictive maintenance is crucial. In order to have efficient predictive maintenance, knowing the performance of critical equipment of production line such as pumps and hydro-cyclones under variable operating parameters, selecting best indicators of this equipment health situations, best locations for instrumentation, and also measuring of these indicators are very important. In this paper, computer aided engineering (CAE) tools are implemented to study some important elements of copper process line, namely slurry pumps and cyclone to predict the performance of these components under different working conditions. These modeling and simulations can be used in predicting, for example, the damage tolerance of the main shaft of the slurry pump or wear rate and location of cyclone wall or pump case and impeller. Also, the simulations can suggest best-measuring paramete...

Predicting the shock isolation behavior of a hydraulic engine mount by 3D finite element modeling of fluid-structure-interaction

هب عاجرا يارب دییامن هدافتسا لیذ ترابع زا هلاقم نیا : Please cite this article using: K. Jahani, ... more هب عاجرا يارب دییامن هدافتسا لیذ ترابع زا هلاقم نیا : Please cite this article using: K. Jahani, M. Dehnad, Predicting the shock isolation behavior of a hydraulic engine mount by 3D inite element modeling of luid-structure-interaction, Modares Mechanical Engineering, Vol. 14, No. 4, pp. 122-128, 2014 (In Persian) شیپ ینیب لدم اب كوش کیرحت ندرک هلوزیا رد یکیلوردیه روتوم هتسد کی راتفر يزاس هس دودحم ازجا رب يدعب مه هزاس شنک لایس

Predictingtheshockisolationbehaviorofahydraulicenginemountby3D finite element modeling of fluid-structure-interaction

هب عاجرا يارب دییامن هدافتسا لیذ ترابع زا هلاقم نیا : Please cite this article using: K. Jahani, ... more هب عاجرا يارب دییامن هدافتسا لیذ ترابع زا هلاقم نیا : Please cite this article using: K. Jahani, M. Dehnad, Predicting the shock isolation behavior of a hydraulic engine mount by 3D inite element modeling of luid-structure-interaction, Modares Mechanical Engineering, Vol. 14, No. 4, pp. 122-128, 2014 (In Persian) شیپ ینیب لدم اب كوش کیرحت ندرک هلوزیا رد یکیلوردیه روتوم هتسد کی راتفر يزاس هس دودحم ازجا رب يدعب مه هزاس شنک لایس

Hybrid method for studying the effect of the material change on the blade vibration behavior

To increase the production efficiency of a typical turbine blade, it is necessary to change its m... more To increase the production efficiency of a typical turbine blade, it is necessary to change its material and hence its production technology. In this respect and in order to make sure that newmaterial will not bring about the blade resonant vibrations, the common practice is to use the Campbell diagram approach. This approach only indicates the potential dangers for blade forced vibration. The purpose of this paper is to demonstrate the efficiency of a proposed hybrid procedure for the development of a reliable Campbell diagram, using an updated finite elementmodel and a simplified test setup.

Identification of Parameters of Spencer Model for a Double-Ended Magnetorheological Damper with Different Spherical Iron Carbonyl Powder Sizes

Development of a laboratory system to investigate and store electrical energy from the vibrations of a piezoelectric beam

Environmental Engineering Science, 2016

Energy harvesting from surrounding environment has been attractive for many researchers in recent... more Energy harvesting from surrounding environment has been attractive for many researchers in recent years. Therefore, developing appropriate test apparatus to study energy harvesting mechanisms and their performance is of paramount importance. Due to their electromechanical characteristics, piezoelectric materials are used for harvesting energy from environmental vibrations. For optimum utilization of this system in harvesting and storing energy, the studies need to consider the environmental conditions. In this work, the electromechanical system is developed with the aim of conducting tests on piezoelectric materials. It is an integrated system which is developed and built after considering the limitations and sensitivity of piezoelectric material. In this research, the simple piezoelectric beam is also tested. Evaluation results via this system are analysed using Abaqus. The error value in receiving output voltage is 6% because an ideal open circuit state is considered by this softw...

Experimental Study of the Effects of Iron Particles Size on Damping Force and Energy Dissipation of a Double-Ended Magnetorheological Damper

Cold spray deformation and deposition of blended feedstock powders not necessarily obey the rule of mixture

Surface and Coatings Technology, 2021

Abstract Cold spray additive manufacturing has the potential to be used in repair and manufacturi... more Abstract Cold spray additive manufacturing has the potential to be used in repair and manufacturing of a wide variety of parts and coatings including composite coatings. Understanding materials' fundamental behaviour during deposition is essential for the process development which was not addressed enough for mixed powders. One objective of this study is to explore the process-structure relation of mixed Ni-Ti powders in cold spray to provide a methodology to achieve a coating with the composition of interest. Single/multi-particle impact experiments and FEM modelling were employed to investigate the particle deformation and microstructure evolution using SEM, EBSD and EDS. The sprays of mixed powders were performed using a wide process parameter window and the deposition characteristics and composition variation as a function of process parameters were explored. The experiments and modelling showed that splats in dissimilar multi-particle impacts experience more deformation than those of similar materials, which in microstructural scale translates to variation of deformation mechanism from single-component coatings. This results in higher degree of grain refinement, specifically for Ti in the composite coating with an average grain size of 500 nm. Experiments showed that the DE of mixed powder deviates from the rule of mixture, which means the critical velocity of Ni-Ti powder is different from the single-component Ni and Ti coatings due to material interactions. Findings showed there is a process parameter criteria for which relative DEs of components, and thereby composition of composite coatings, remain at almost constant ratios. η (impact velocity/critical velocity ratio) is used as a measure to predict qualitative composition variation as a function of spraying parameters and powder characteristics.

Identifying the parameters of viscoelastic model for a gel-type material as representative of cardiac muscle in dynamic tests

Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 2021

In this paper, mechanical parameters of a calf heart muscle are identified and a gel-type materia... more In this paper, mechanical parameters of a calf heart muscle are identified and a gel-type material as the representative of the cardiac muscle in dynamic tests is introduced. The motivation of this study is to introduce a replacement material of the heart muscle to use in experimental studies of the leadless pacemaker. A particular test setup is developed to capture the experimental data based on the stress relaxation test method where its outputs are time histories of the force and displacement. The standard linear solid model is used for mathematical modeling of the heart muscle sample and a gel-type material specimen namely α-gel. Five tests with different strain history [Formula: see text] are performed by regarding and disregarding the influence of the initial ramp of the loading. The mechanical parameters of the standard linear solid model were identified with precise curve fitting. Consideration of the initial ramp significantly influences the consequences and they are so clo...

Dynamic microstructure evolution in cold sprayed Ni Ti composite coatings

Surface and Coatings Technology, 2021

Abstract The severe plastic deformation inherent to cold spray provides a unique opportunity to s... more Abstract The severe plastic deformation inherent to cold spray provides a unique opportunity to study dynamic microstructure evolution under extremely high strain rates, not achievable in conventional laboratory experiments. In this study, the correlation between dynamic deformation and microstructure evolution is investigated for a heterogeneous system, using cold spray of blended Ni Ti powder mixtures. EBSD analyses of the Ni and Ti particles show different degrees of dynamic recrystallization (DRX) especially at particle boundaries, which are attributed to different materials properties and dissimilar materials interaction. A heterogeneous structure of Ni Ti composite was achieved with Ni particle being embedded in an ultra-fine grain Ti matrix with an average grain size of 500 nm. Results show hierarchical structures including twins with a thickness of about 500 nm, micro-bands and low angle boundaries, which are associated with a grain subdivision mechanism through continuous dynamic recrystallization (CDRX). The results also demonstrate a drastically different response of Ti and Ni to the same loading conditions, hence provide an insight to the role of intrinsic material properties in DRX at extremely high strain rates.

Experimental and numerical study on the performance of printed alginate/hyaluronic acid/halloysite nanotube/polyvinylidene fluoride bio-scaffolds

Journal of Biomechanics, 2020

 The comparative experiments between the MPVTW and EPVTW are carried out.  Simulation models fo... more