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Volume 43, Number 5, June10 2022

Turbocharger technology is one of the ways to survive in a competitive market that is facing increasing demand for fuel and improving the efficiency of vehicle engines. Turbocharging allows the engine to operate at close to its maximum power, thereby reducing the relative friction losses. One way to optimally understand the behavior of a turbocharger is to better understand the heat flow. In this paper, a 1.7 liter, 4 cylinder and 16 air valve gasoline engine turbocharger with compressible, viscous and 3D flow was investigated. The purpose of this paper is numerical investigation of the number of heat transfer in gasoline engines turbochargers under 3D flow and to examine the effect of different types of coatings on its performance; To do this, modeling of snail chamber and turbine blades in CATIA and simulation in ANSYS-FLUENT software have been used to compare the results of turbine with experimental results in both adiabatic and non-adiabatic (heat transfer) conditions. It should be noted that the turbine blades are modeled using multiple rotational coordinate methods. In the experimental section, we simulated our model without coating in two states of adiabatic and non-adiabatic. Then we matched our results with the experimental results to prove the validation of the model. Comparison of numerical and experimental results showed a difference of 8-10%, which indicates the accuracy and precision of numerical results. Also, in our studies, we concluded that the highest effective power of the turbocharged engine is achieved in the adiabatic state. We also used three types of SiO2, Sic and Si3N4 ceramic coatings to investigate the effect of insulating coatings on turbine shells to prevent heat transfer. The results showed that SiO2 has better results than the other two coatings due to its lower heat transfer coefficient.

Key Words
ceramic coating; engine power; heat transfer; turbocharger

Ali Pakbin, Hamidreza Tabatabaei and Hossein Nouri-Bidgoli:Department of Mechanical Engineering, Kashan Branch, Islamic Azad University, Kashan, Iran

The current article deals with the dynamic stability, and structural improvement of vibrating electrically curved screen on the viscoelastic substrate. By considering optimum value for radius curvature of the electrically curved screen, the structure improvement of the system occurs. For modeling the electrically system, the Maxwell's' equation is developed. Hertz contact model in employed to obtain contact forces between impactor and structure. Moreover, variational methods and nonlinear von Kármán model are used to derive boundary conditions (BCs) and nonlinear governing equations of the vibrating electrically curved screen. Galerkin and Multiple scales solution approach are coupled to solve the nonlinear set of governing equations of the vibrating electrically curved screen. Along with the analytical solution, 3D finite element simulation via ABAQUS package is provided with the aid of a FE package for simulating the current system's response. The results are categorized in 3 different sections. First, effects of geometrical and material parameters on the vibrational performance and stability of the curves panel. Second, physical properties of the impactor are taken in to account and their effect on the absorbed energy and velocity profile of the impactor are presented. Finally, effect of the radius and initial velocity on the mode shapes of the current structure is demonstrated.

Key Words
Coupled Galerkin and Multiple Scales methods; Energy absorption; structural improvement; vibrating electrically curved screen; Von-Karman nonlinearity

Caiyuan Xiao and Guiju Zhang:1)Key Laboratory of Hunan Province for Efficient Power System and Intelligent Manufacturing, Shaoyang 422000, Hunan, China
2)College of Mechanical and Energy Engineering, Shaoyang University, Shaoyang 422000, Hunan, China

Many existing reinforced concrete (RC) structures need to be strengthening for reason such as poor construction quality, low ductility or designing without considering seismic effects. One of the strengthening methods is strengthening technique with eccentrically braced frames (EBFs). The characteristic element of these systems is the link element and its length is very important in terms of seismic behavior. The link element of Y shaped EBF systems (YEBFs) is designed as a short shear element. Different limits are suggested in the literature for the link length. This study to aim experimentally investigate the effect of the link length for the suggested limits on the behavior of the RC frame system and efficiency of strengthening technique. For this purpose, a total of 5 single story, single span RC frame specimens were produced. The design of the RC frames was made considering seismic design deficiencies. Four of the produced specimens were strengthened and one of them remained as bare specimen. The steel YEBFs were used in strengthening the RC frame and the link was designed as a shear element that have different length with respect to suggested limits in literature. The length of links was determined as 50mm, 100 mm, 150m m and 200 mm. All of the specimens were tested under cyclic loads. The obtained results show that the strengthening technique improved the energy consumption and lateral load bearing capacities of the bare RC specimen. Moreover, it is concluded that the specimens YB-2 and YB-3 showed better performance than the other specimens, especially in energy consumption and ductility.

Key Words
inverted Y brace; RC frame; shear link; steel braced; strengthening; vertical link

Gulhan INCE:Department of Civil Engineering, Architectural and Engineering Faculty, Burdur Mehmet Akif Ersoy University, 15030 Burdur, Turkey

This study investigated the yielding capacity and performance of seismic dampers constructed with steel ring plates using numerical and analytical approaches. This study aims to provide an analytical relationship for estimating the yielding capacity and initial stiffness of steel ring dampers. Using plastic analysis and considering the mechanism of plastic hinge formation, a relation has been obtained for estimating the yielding capacity of steel ring dampers. Extensive parametric studies have been carried out using a nonlinear finite element method to examine the accuracy of the obtained analytical relationships. The parametric studies include investigating the influence of the length, thickness, and diameter of the ring of steel ring dampers. To this end, comprehensive verification studies are performed by comparing the numerical predictions with several reported experimental results to demonstrate the numerical method's reliability and accuracy. Comparison is made between the hysteresis curves, and failure modes predicted numerically or obtained/observed experimentally. Good agreement is observed between the numerical simulations and the analytical predictions for the yielding force and initial stiffness. The difference between the numerical models' ultimate tensile and compressive capacities was observed that average of about 22%, which stems from the performance of the ring-dampers in the tensile and compression zones. The results show that the steel ring-dampers are exhibited high energy dissipation capacity and ductility. The ductility parameters for steel ring-damper between values were 7.5 to 4.1.

Key Words
cohesive surface contact; cylindrical shell; sandwich structure; shell/core debonding; truss core

Ali Mohammad Rousta:Department of Civil Engineering, Yasouj University, Yasouj, Iran

Mojtaba Gorji Azandariani:1)Centre for Infrastructure Engineering, Western Sydney University, Penrith, Australia
2) Structural Engineering Division, Faculty of Civil Engineering, Semnan University, Semnan, Iran

The main objective of this research work is to investigate the free vibration behavior of annular sandwich plates resting on the Kerr foundation at thermal conditions. This sandwich configuration is composed of two FGM face sheets as coating layer and a porous GPLRC (GPL reinforced composite) core. It is supposed that the GPL nanofillers and the porosity coefficient vary continuously along the core thickness direction. To model closed-cell FG porous material reinforced with GPLs, Halpin-Tsai micromechanical modeling in conjunction with Gaussian-Random field scheme is used, while the Poisson's ratio and density are computed by the rule of mixtures. Besides, the material properties of two FGM face sheets change continuously through the thickness according to the power-law distribution. To capture fundamental frequencies of the annular sandwich plate resting on the Kerr foundation in a thermal environment, the analysis procedure is with the aid of Reddy's shear-deformation plate theory based high-order shear deformation plate theory (HSDT) to derive and solve the equations of motion and boundary conditions. The governing equations together with related boundary conditions are discretized using the generalized differential quadrature (GDQ) method in the spatial domain. Numerical results are compared with those published in the literature to examine the accuracy and validity of the present approach. A parametric solution for temperature variation across the thickness of the sandwich plate is employed taking into account the thermal conductivity, the inhomogeneity parameter, and the sandwich schemes. The numerical results indicate the influence of volume fraction index, GPLs volume fraction, porosity coefficient, three independent coefficients of Kerr elastic foundation, and temperature difference on the free vibration behavior of annular sandwich plate. This study provides essential information to engineers seeking innovative ways to promote composite structures in a practical way.

Key Words
FGM; kerr elastic foundation; porous graphene nanoplatelet reinforced composite; sandwich structures; thermal effects; vibration analysis

Zhe Zhang:Architectural Engineering Institute, Rizhao Polytechnic, Rizhao,Shandong, 276826, China

Qijian Yang:Rizhao Tiantai Construction and Installation Engineering Co. LTD, Rizhao, Shandong, 276826, China

Cong Jin:Architectural Engineering Institute, Rizhao Polytechnic, Rizhao,Shandong, 276826, China

This article is dedicated to predict the natural frequencies of joined conical shell structures made of Functionally Graded Material (FGM). The structure includes two conical segments. The equivalent material properties are found by using the rule of mixture based on Voigt model. In addition, three well-known patterns are employed for distribution of material properties throughout the thickness of the structure. The main objective of the present research is to propose a novel exponential pattern and obtain the related equivalent material properties. Furthermore, the Donnell type shell theory is used to obtain the governing equations of motion. Note that these equations are obtained by employing First-order Shear Deformation Theory (FSDT). In order to discretize the governing system of differential equations, well-known and efficient semi-analytical scheme, namely Generalized Differential Quadrature Method (GDQM), is utilized. Different boundary conditions are considered for various types of single and joined conical shell structures. Moreover, an applicable modification is considered for the continuity conditions at intersection position. In the first step, the proposed formulation is verified by solving some well-known benchmark problems. Besides, some new numerical examples are analyzed to show the accuracy and high capability of the suggested technique. Additionally, several geometric and material parameters are studied numerically.

Key Words
free vibration; joined conical-conical shell; FGM; modified GDQM; continuity conditions

Mohammad Rezaiee-Pajand, Emad Sobhani and Amir R. Masoodi:Department of Civil Engineering, Ferdowsi University of Mashhad, Mashhad, Iran

Axial compression capacity (Pu) is a significant yet complex parameter of concrete-filled steel tube (CFST) columns. This study offers a novel ensemble tool, adaptive neuro-fuzzy inference system (ANFIS) supervised by equilibrium optimization (EO), for accurately predicting this parameter. Moreover, grey wolf optimization (GWO) and Harris hawk optimizer (HHO) are considered as comparative supervisors. The used data is taken from earlier literature provided by finite element analysis. ANFIS is trained by several population sizes of the EO, GWO, and HHO to detect the best configurations. At a glance, the results showed the competency of such ensembles for learning and reproducing the Pu behavior. In details, respective mean absolute errors along with correlation values of 4.1809% and 0.99564, 10.5947% and 0.98006, and 4.8947% and 0.99462 obtained for the EO-ANFIS, GWO-ANFIS, and HHO-ANFIS, respectively, indicated that the proposed EO-ANFIS can analyze and predict the behavior of CFST columns with the highest accuracy. Considering both time and accuracy, the EO provides the most efficient optimization of ANFIS and can be a nice substitute for experimental approaches.

Key Words
deformation demand; earthquake resistant design philosophy; limit states; structural damage states; levels of earthquake shaking

Yuxin Zheng:School of Civil Engineering and Architecture, Zhejiang Guangsha Vocational and Technical University of Construction,Dongyang 322100, Zhejiang, China

Hongwei Jin:School of Civil Engineering and Architecture, Zhejiang Guangsha Vocational and Technical University of Construction,Dongyang 322100, Zhejiang, China

Congying Jiang:School of Civil Engineering and Architecture, Zhejiang Guangsha Vocational and Technical University of Construction,Dongyang 322100, Zhejiang, China

Zohre Moradi:Faculty of Engineering and Technology, Department of Electrical Engineering, Imam Khomeini International University,
34149-16818 Qazvin, Iran

Mohamed Amine Khadimallah:1)Prince Sattam Bin Abdulaziz University, College of Engineering, Civil Engineering Department, Al-Kharj, 16273, Saudi Arabia
2)Laboratory of Systems and Applied Mechanics, Polytechnic School of Tunisia, University of Carthage, Tunis, Tunisia

Hossein Moaye:Faculty of Civil Engineering, Duy Tan University, Da Nang 550000, Vietnam

The bending and buckling behaviours of FG-GRNC laminated sandwich plates are investigated by using novel five-variables quasi 3D higher order shear deformation plate theory by considering the modified continuum nonlocal strain gradient theory. To calculate the effective Young's modulus of the GRNC sandwich plate along the thickness direction, and Poisson's ratio and mass density, the modified Halpin-Tsai model and the rule of the mixture are employed. Based on a new field of displacement, governing equilibrium equations of the GRNC sandwich plate are solved using a developed approach of Galerkin method. A detailed parametric analysis is carried out to highlight the influences of length scale and material scale parameters, GPLs distribution pattern, the weight fraction of GPLs, geometry and size of GPLs, the geometry of the sandwich plate and the total number of layers on the stresses, deformation and critical buckling loads. Some details are studied exclusively for the first time, such as stresses and the nonlocality effect.

Key Words
bending and buckling responses; five-variable 3D nonlocal shear deformation theory; Galerkin Method; graphene platelet; material and length scale parameters; reinforced composite plate

Muhammad Basha:Faculty of Engineering, Mechanical Engineering Department, King Abdulaziz University, P.O. Box 80204, Jeddah, Saudi Arabia

Ahmed Amine Daikh:1)Department of Technology, University Center of Naama, 45000 Naama, P.O. Box 66, Algeria
2)Laboratoire d'Etude des Structures et de Mecanique des Materiaux, Departement de Genie Civil, Faculte des Sciences et de la Technologie,
Universite Mustapha Stambouli, Mascara, Algerie

Ammar Melaibari:Faculty of Engineering, Mechanical Engineering Department, King Abdulaziz University, P.O. Box 80204, Jeddah, Saudi Arabia

Ahmed Wagih:Faculty of Engineering, Mechanical Design and Production Department, Zagazig University, P.O. Box 44519, Zagazig, Egypt

Ramzi Othman:Faculty of Engineering, Mechanical Engineering Department, King Abdulaziz University, P.O. Box 80204, Jeddah, Saudi Arabia

Khalid H Almitani:Faculty of Engineering, Mechanical Engineering Department, King Abdulaziz University, P.O. Box 80204, Jeddah, Saudi Arabia

Mostafa A. Hamed:Faculty of Engineering, Mechanical Engineering Department, King Abdulaziz University, P.O. Box 80204, Jeddah, Saudi Arabia

Alaa Abdelrahman:Faculty of Engineering, Mechanical Design and Production Department, Zagazig University, P.O. Box 44519, Zagazig, Egypt

Mohamed A. Eltaher:1)Faculty of Engineering, Mechanical Engineering Department, King Abdulaziz University, P.O. Box 80204, Jeddah, Saudi Arabia 2)Faculty of Engineering, Mechanical Design and Production Department, Zagazig University, P.O. Box 44519, Zagazig, Egypt

The solution of contact problems is extremely important as we encounter many situations involving such problems in our daily lives. One of the most important parameters effective in solving contact problems is the materials of the parts in contact. While it is relatively easy to solve the contact mechanics of the systems created with traditional materials with a homogeneous microstructure and mechanical distribution, it may be more difficult to solve the contact problem of new generation materials that do not show a homogeneous distribution. As a result of this situation, it is seen that studies on contact problems of materials that do not exhibit such a homogeneous internal structure and mechanical properties are extremely limited in the literature. In this context, in this study, analytical and numerical analyzes of a contact problem created using functionally graded materials were carried out and the results were evaluated mutually. It has been decided that the contact areas and contact pressures acquired from numerical method are reasonably appropriate with the results obtained from the analytical method.

Key Words
contact mechanics; finite element method; functionally graded layer; theory of elasticity

Murat Yaylaci:Department of Civil Engineering, Recep Tayyip Erdogan University, 53100, Rize, Turkey

Merve Abanoz:Department of Construction Technology, Kastamonu University, 37100, Kastamonu, Turkey

Ecren Uzun Yaylaci:Surmene Faculty of Marine Science, Karadeniz Technical University, 61040, Trabzon, Turkey

Hasan Olmez:Department of Marine Engineering Operations, Karadeniz Technical University, 61040, Trabzon, Turkey

Dursun Murat Sekban:Department of Marine Engineering Operations, Karadeniz Technical University, 61040, Trabzon, Turkey

Ahmet Birinci:Department of Civil Engineering, Karadeniz Technical University, 61080, Trabzon, Turkey

Post-earthquake fire is a major threat since most structures are designed allowing some damage during strong earthquakes, which will expose a more vulnerable structure to post-earthquake fire compared to an intact structure. A series of experimental research on steel-concrete composite beam-to-column joints subjected to fire after cyclic loading has been carried out and a clear reduction of fire resistance due to the partial damage caused by cyclic loading was observed. In this paper, by using ABAQUS a robust finite element model is developed for exploring the performance of steel-concrete composite joints in post-earthquake fire scenarios. After validation of these models with the previously conducted experimental results, a comprehensive numerical analysis is performed, allowing influential parameters affecting the post-earthquake fire behavior of the steel-concrete composite joints to be identified. Specifically, the level of pre-damage induced by cyclic loading is regraded to deteriorate mechanical and thermal properties of concrete, material properties of steel, and thickness of the fire protection layer. It is found that the ultimate temperature of the joint is affected by the load ratio while fire-resistant duration is relevant to the heating rate, both of which change due to the damage induced by the cyclic loading.

Key Words
steel-concrete composite joints, finite-element numerical modeling, experimental results, cyclic loading, post-earthquake fire

Zhongnan Ye:1)College of Civil Engineering, Tongji University, 200092, Shanghai, China
2)Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, 999077, Hong Kong SAR

Amin Heidarpour:3Department of Civil Engineering, Monash University, VIC 3800, Melbourne, Australia

Shouchao Jiang:College of Civil Engineering, Tongji University, 200092, Shanghai, China

Yingchao Li:College of Civil Engineering, Tongji University, 200092, Shanghai, China

Guoqiang Li:College of Civil Engineering, Tongji University, 200092, Shanghai, China

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