Amirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-603255420230622Optimal cooperative braking strategy design of regenerative and mechanical braking systems for in-wheel drive electric vehiclesOptimal cooperative braking strategy design of regenerative and mechanical braking systems for in-wheel drive electric vehicles433460518210.22060/mej.2023.21842.7522FAAliHosseini SalariDepartment of Mechanical Engineering, Shahid Bahonar University of KermanHosseinMirzaeinejadDepartment of Mechanical Engineering, Shahid Bahonar university of Kerman, Kerman, IranMajidFooladi MahaniDepartment of Mechanical Engineering, Shahid Bahonar university of Kerman, Kerman, IranJournal Article20221010Nowadays, a new generation of electric vehicles with in-wheel motor technology has been introduced and is being developed. Increasing system efficiency, eliminating mechanical intermediaries, and achieving regenerative braking torque with better performance are the motivations to seek to improve this technology. In the present study, a half-car model with five degrees of freedom has been developed by considering a vehicle equipped with two in-wheel motors on the rear axle as a sample vehicle. Then, the braking strategy has been designed using a two-stage nonlinear predictive controller. The appropriate pressure for the brake fluid lines will be reached in the first stage. In the second stage, the proper amount of electric regenerative torque is obtained using the electronic braking force distribution function and considering all constraints. The amount of regenerative torque is calculated by considering the system constraints using the Karush–Kuhn–Tucker conditions. Finally, the designed strategy is examined from the perspective of vehicle mileage capability. The results show that optimal braking can be achieved by utilizing the designed controller and the proposed model. Also, the amount of regenerated energy to the battery can be increased during braking by using the proposed braking strategy and the designed control system in comparison with the relevant studies.Nowadays, a new generation of electric vehicles with in-wheel motor technology has been introduced and is being developed. Increasing system efficiency, eliminating mechanical intermediaries, and achieving regenerative braking torque with better performance are the motivations to seek to improve this technology. In the present study, a half-car model with five degrees of freedom has been developed by considering a vehicle equipped with two in-wheel motors on the rear axle as a sample vehicle. Then, the braking strategy has been designed using a two-stage nonlinear predictive controller. The appropriate pressure for the brake fluid lines will be reached in the first stage. In the second stage, the proper amount of electric regenerative torque is obtained using the electronic braking force distribution function and considering all constraints. The amount of regenerative torque is calculated by considering the system constraints using the Karush–Kuhn–Tucker conditions. Finally, the designed strategy is examined from the perspective of vehicle mileage capability. The results show that optimal braking can be achieved by utilizing the designed controller and the proposed model. Also, the amount of regenerated energy to the battery can be increased during braking by using the proposed braking strategy and the designed control system in comparison with the relevant studies.https://mej.aut.ac.ir/article_5182_5cde6dedeb8892e3794f22db57ada073.pdfAmirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-603255420230622Chatter Suppression in turning by applying a tooling mechanism with the ability to change the tool anglesChatter Suppression in turning by applying a tooling mechanism with the ability to change the tool angles461474517210.22060/mej.2023.5172.7490FAHosseinBehrouzBabol Noshirvani University of Technology, Babol, Iran.HamidBaseriBabol Noshirvani University of Technology, Babol, Iran.HosseinNourmohamdiMalek Ashtar University of TechnologyJournal Article20220816Tool angles have a great impact on cutting mechanics and the machining parameters such as surface quality, tool life, specific cutting energy, and dynamic stability of the cutting process<strong>.</strong> One of the research topics in this field is the development of mechanisms that can be used to create more control on the machining process, such as the tool angles, simultaneously in the process. In this research, a tooling mechanism has been presented for the turning machine, which provides the ability to adjust the normal rake and clearance angles, during the turning process. This mechanism is used to develop a new active control system for chatter suppression for increasing the dynamic stability of the turning process. In this technique, the controller detects the chatter through the acceleration sensor and then reduces the clearance angle of the tool by using the mechanism, this increases the process damping and by increasing the overall damping, it suppresses the vibrations. To design the active controller, the simulation was done in the MATLAB-Simulink and then according to the simulation results, an on/off controller was designed and implemented. Then, experimental tests were performed to evaluate the performance of the chatter suppression control system. The test results showed that the proposed method can have a good effect in reducing chatter vibrations in the turning process and leads to a significant increase in the stability of the tuning process.Tool angles have a great impact on cutting mechanics and the machining parameters such as surface quality, tool life, specific cutting energy, and dynamic stability of the cutting process<strong>.</strong> One of the research topics in this field is the development of mechanisms that can be used to create more control on the machining process, such as the tool angles, simultaneously in the process. In this research, a tooling mechanism has been presented for the turning machine, which provides the ability to adjust the normal rake and clearance angles, during the turning process. This mechanism is used to develop a new active control system for chatter suppression for increasing the dynamic stability of the turning process. In this technique, the controller detects the chatter through the acceleration sensor and then reduces the clearance angle of the tool by using the mechanism, this increases the process damping and by increasing the overall damping, it suppresses the vibrations. To design the active controller, the simulation was done in the MATLAB-Simulink and then according to the simulation results, an on/off controller was designed and implemented. Then, experimental tests were performed to evaluate the performance of the chatter suppression control system. The test results showed that the proposed method can have a good effect in reducing chatter vibrations in the turning process and leads to a significant increase in the stability of the tuning process.https://mej.aut.ac.ir/article_5172_08fc80de8121419136e443a70489c123.pdfAmirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-603255420230622Developing a new functionally graded lattice structure based on an elliptic unit cell for additive manufacturing and investigation of its propertiesDeveloping a new functionally graded lattice structure based on an elliptic unit cell for additive manufacturing and investigation of its properties475494514110.22060/mej.2023.21736.7504FAHedyehMojaveryAgahFaculty of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, IranMasoodAsgariFaculty of Mechanical Engineering, K. N. Toosi University of Technology, Tehran, Iran0000-0002-2063-8699Journal Article20220904The use of additive manufacturing provides the opportunity to create complex geometries at a low cost. This paper introduces a novel nature-inspired additive manufactured graded lattice structure based on an elliptic unit cell. Altering the unit cells' dimensions by the dimension ratios in each repetition results in a graded layer. Linear tessellated layers provide a highly porous, graded structure whose specific properties can be customized at any spatial location. Geometric features were calculated with high accuracy using analytical analysis. Abaqus simulations were utilized to determine the mechanical properties of unit cells, layers, and lattices. A compression test was conducted on a polymer specimen made by digital light processing (DLP) to validate the results. For a conformal model, the elastic modulus along the latitude axis is five times bigger than the value along the longitude axis. An 8.8-fold increase in the elastic modulus is achievable by decreasing the longitude ratio from 1 to 0.75. A reduction of 0.3% in porosity by setting the longitude ratio to 0.75 and a decrease of 2% in porosity by lessening the latitude ratio to 0.75 results in increases of 2.6 and 2.77 folds in the elastic modulus along two directions, respectively. It is possible to tailor geometrical and mechanical properties to meet any design preference by selecting the proper dimension ratios, which can be utilized for medical implant design.The use of additive manufacturing provides the opportunity to create complex geometries at a low cost. This paper introduces a novel nature-inspired additive manufactured graded lattice structure based on an elliptic unit cell. Altering the unit cells' dimensions by the dimension ratios in each repetition results in a graded layer. Linear tessellated layers provide a highly porous, graded structure whose specific properties can be customized at any spatial location. Geometric features were calculated with high accuracy using analytical analysis. Abaqus simulations were utilized to determine the mechanical properties of unit cells, layers, and lattices. A compression test was conducted on a polymer specimen made by digital light processing (DLP) to validate the results. For a conformal model, the elastic modulus along the latitude axis is five times bigger than the value along the longitude axis. An 8.8-fold increase in the elastic modulus is achievable by decreasing the longitude ratio from 1 to 0.75. A reduction of 0.3% in porosity by setting the longitude ratio to 0.75 and a decrease of 2% in porosity by lessening the latitude ratio to 0.75 results in increases of 2.6 and 2.77 folds in the elastic modulus along two directions, respectively. It is possible to tailor geometrical and mechanical properties to meet any design preference by selecting the proper dimension ratios, which can be utilized for medical implant design.https://mej.aut.ac.ir/article_5141_130ea938864f051b9a40c85b6a713306.pdfAmirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-603255420230622Three-dimensional micromechanical modelling of effective elastic properties of graphene nanoplatelet-reinforced polymer nanocomposite using a HFGMC-based homogenization approachThree-dimensional micromechanical modelling of effective elastic properties of graphene nanoplatelet-reinforced polymer nanocomposite using a HFGMC-based homogenization approach495514513710.22060/mej.2023.22059.7560FAHadiMehdipourFaculty of Mechanical and Energy Engineering, Shahid Beheshti University,Tehran, IranAbbasRohani BastamiFaculty of Mechanical and Energy Engineering, Shahid Beheshti University,Tehran, IranMohammad HosseinSoorgeeFaculty of Mechanical and Energy Engineering, Shahid Beheshti University,Tehran, Iran0000-0002-7758-7001Journal Article20221227A three-dimensional analytical micromechanical model based on the unit cell is extended to extract the elastic properties of graphene-nanoplatelet reinforced polymer nanocomposites. Graphene-nanoplatelet /epoxy interphase region changing gradually is considered elastic with isotropic behavior. To simulate the random distribution of graphene, the geometry of the representative volume element of the nanocomposite is divided into a three-dimensional cubic with subcells. The obtained results are compared with the available research studies. Moreover, the effect of parameters such as the volume of graphene-nanoplatelet in the epoxy resin, the graphene-nanoplatelet aggregation, and the interphase region are investigated on the response of the nanocomposite. It is shown that the aggregation of graphene-nanoplatelet depends on its volume fraction. The results show that the elastic properties obtained from the present micromechanical model taking into account the random distribution, the agglomeration of nanoparticles, and also interphase are close to the experimental data.A three-dimensional analytical micromechanical model based on the unit cell is extended to extract the elastic properties of graphene-nanoplatelet reinforced polymer nanocomposites. Graphene-nanoplatelet /epoxy interphase region changing gradually is considered elastic with isotropic behavior. To simulate the random distribution of graphene, the geometry of the representative volume element of the nanocomposite is divided into a three-dimensional cubic with subcells. The obtained results are compared with the available research studies. Moreover, the effect of parameters such as the volume of graphene-nanoplatelet in the epoxy resin, the graphene-nanoplatelet aggregation, and the interphase region are investigated on the response of the nanocomposite. It is shown that the aggregation of graphene-nanoplatelet depends on its volume fraction. The results show that the elastic properties obtained from the present micromechanical model taking into account the random distribution, the agglomeration of nanoparticles, and also interphase are close to the experimental data.https://mej.aut.ac.ir/article_5137_d903e9608cfbf08910611e4346a0ba44.pdfAmirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-603255420230622Buckling analysis of tapered laminated composite channel-section beam-columns subjected to combined axial load and end momentBuckling analysis of tapered laminated composite channel-section beam-columns subjected to combined axial load and end moment515542517610.22060/mej.2023.21799.7513FARezaAbolghasemianDepartment of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, Kashan, IranMasoumehSoltaniDepartment of Civil Engineering, Faculty of Engineering, University of Kashan, Kashan, IranAhmad RezaGhasemiDepartment of Solid Mechanics, Faculty of Mechanical Engineering, University of Kashan, Kashan, Iran0000-0002-9326-4990Journal Article20220923Nowadays, the practical applications of shell elements such as beams having thin-wall cross-sections are increasing greatly in various fields of engineering including aerospace, nuclear, marine, and automotive industries. This is due to their ability to optimally use structural materials and simultaneously reduce the total weight of the structure. Fiber polymer composites also have different conspicuous properties such as high stiffness-to-weight and strength-to-weight ratios, corrosion resistance, and high strength. Therefore, laminated composite C-section beam elements simultaneously possess both the beneficial features of fiber-reinforced composite materials and thin-walled cross-sections at the same time. Motivated by these facts, in this research, the flexural-torsional stability of multi-layer fibrous composite tapered beam-columns with channel-section subjected to axial and bending loads is investigated. For this purpose, the total potential energy governing the problem is extracted based on Vlasov’s model for small non-uniform torsion along with the classical laminated plate theory. Then, using Ritz’s methodology as an analytical solution technique, the endurable buckling load is calculated. Eventually, the effect of important parameters such as stacking sequences, fiber composite materials, boundary conditions, axial load eccentricity, and axial preloading on the linear buckling capacity of double-tapered multi-layer composite beam-column with channel-section under axial load and end moment is investigated.Nowadays, the practical applications of shell elements such as beams having thin-wall cross-sections are increasing greatly in various fields of engineering including aerospace, nuclear, marine, and automotive industries. This is due to their ability to optimally use structural materials and simultaneously reduce the total weight of the structure. Fiber polymer composites also have different conspicuous properties such as high stiffness-to-weight and strength-to-weight ratios, corrosion resistance, and high strength. Therefore, laminated composite C-section beam elements simultaneously possess both the beneficial features of fiber-reinforced composite materials and thin-walled cross-sections at the same time. Motivated by these facts, in this research, the flexural-torsional stability of multi-layer fibrous composite tapered beam-columns with channel-section subjected to axial and bending loads is investigated. For this purpose, the total potential energy governing the problem is extracted based on Vlasov’s model for small non-uniform torsion along with the classical laminated plate theory. Then, using Ritz’s methodology as an analytical solution technique, the endurable buckling load is calculated. Eventually, the effect of important parameters such as stacking sequences, fiber composite materials, boundary conditions, axial load eccentricity, and axial preloading on the linear buckling capacity of double-tapered multi-layer composite beam-column with channel-section under axial load and end moment is investigated.https://mej.aut.ac.ir/article_5176_843a4d7fb5b1641b0bb8e3c2b2e75231.pdfAmirkabir University of TechnologyAmirkabir Journal of Mechanical Engineering2008-603255420230622A Numerical and Experimental Study on Fatigue Crack Growth of Ti-6Al-4V Specimens in Presence of Tensile Residual StressesA Numerical and Experimental Study on Fatigue Crack Growth of Ti-6Al-4V Specimens in Presence of Tensile Residual Stresses543554518110.22060/mej.2023.22012.7556FAAmirMohammadZangenehDepartment of Mechanical Engineering, Amirkabir University of TechnologyIrajSattarifarDepartment of Mechanical Engineering, Amirkabir University of TechnologyMohammadNoghabiDepartment of Mechanical Engineering, Amirkabir University of TechnologyJournal Article20221219<span style="letter-spacing: .05pt;">Fatigue crack growth is one of the failure mechanisms in engineering structures, which is intensified by the presence of tensile residual stress. In this research, the effect of tensile residual stress in front of the crack front on fatigue crack growth has been investigated. The mechanical residual stress has been applied to the samples using the four-point bending method, and the residual stress has also been measured using the hole drilling method. Fatigue crack growth tests were performed on single edge notch bend samples with residual stress and without residual stress and the repeatability of the test was checked. To investigate the plastic area ahead of the crack tip, the applied residual stress, and obtain the fracture mechanics parameters, Abaqus commercial software has been used. The results of this study show the increase in the rate of fatigue crack growth in the presence of tensile residual stress. This increase in fatigue crack growth rate can reduce fatigue life up to 50%.</span><span style="letter-spacing: .05pt;">Fatigue crack growth is one of the failure mechanisms in engineering structures, which is intensified by the presence of tensile residual stress. In this research, the effect of tensile residual stress in front of the crack front on fatigue crack growth has been investigated. The mechanical residual stress has been applied to the samples using the four-point bending method, and the residual stress has also been measured using the hole drilling method. Fatigue crack growth tests were performed on single edge notch bend samples with residual stress and without residual stress and the repeatability of the test was checked. To investigate the plastic area ahead of the crack tip, the applied residual stress, and obtain the fracture mechanics parameters, Abaqus commercial software has been used. The results of this study show the increase in the rate of fatigue crack growth in the presence of tensile residual stress. This increase in fatigue crack growth rate can reduce fatigue life up to 50%.</span>https://mej.aut.ac.ir/article_5181_3b7d09dac07c9ccd3aae2025cc195250.pdf