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CONTENTS
Volume 48, Number 6, September 25 2023
 

Abstract
This work considered an optimal control formulation in the sense of Caputo derivatives. The optimality of the fractional optimal control problem. The tumor immune interaction in fractional form provides an excellent tool for the description of memory and hereditary properties of inter and intra cells. So the interaction between effector-cells, tumor cells and are modeled by using the definition of Caputo fractional order derivative that provides the system with long-time memory and gives extra degree of freedom. In addiltion, existence and local stability of fixed points are investigated for discrete model. Moreover, in order to achieve more efficient computational results of fractional-order system, a discretization process is performed to obtain its discrete counterpart. Our technique likewise allows the advancement of results, such as return time to baseline that are unrealistic with current model solvers.

Key Words
Caputo derivatives; discretization process; fractional-order system; hereditary properties

Address
Muzamal Hussain:Department of Mathematics, Govt. College University Faisalabad, 38000, Faisalabad, Pakistan

Saima Akram and Madeeha Tahir: Department of Mathematics, Govt. College Women University Faisalabad, 38000, Faisalabad, Pakistan

Mohamed A. Khadimallah:Department of Civil Engineering, College of Engineering in Al-Kharj, Prince Sattam Bin Abdulaziz University, Al-Kharj, 11942, Saudi Arabia

Shabir Ahmad:Department of Mathematics, Govt. College University Faisalabad, 38000, Faisalabad, Pakistan

Mohammed Alsaigh:Faculty of Economics and administration, King Abdulaziz University, Jeddah, Saudi Arabia

Abdelouahed Tounsi:1)YFL (Yonsei Frontier Lab), Yonsei University, Seoul, Korea
2)Department of Civil and Environmental Engineering, King Fahd University of Petroleum and Minerals,31261 Dhahran, Eastern Province,
Saudi Arabia

Abstract
In this paper, a Taguchi-based finite element method (FEM) has been proposed and implemented to assess optimal design parameters for minimum static deflection in laminated composite plate. An orthodox mathematical model (based on higher-order shear deformation plate theory and Green-Lagrange geometrical nonlinearity) has been used to compute the nonlinear central deflection values of laminated composite plates according to Taguchi design of experiment via a selfdeveloped MATLAB computer code. The lay-up scheme, aspect ratio, thickness ratio and the support conditions of the laminated composite plate structure were designated as the governable design parameters. Analysis of variance (ANOVA) is used to investigate the effect of diverse control factors on the nonlinear static responses. Moreover, regression model is developed for predicting the desired responses. The ANOVA revealed that the lay-up scheme alongside the support condition plays vital role in minimizing the central deflection values of laminated composite plate under uniformly distributed load. The conformity test results of Taguchi analysis are also in good agreement with the numerical experimentation results.

Key Words
ANOVA; laminated composite plate; nonlinear FEM; static deflection; Taguchi method

Address
Pratyush Kumar Sahu, Trupti Ranjan Mahapatra and Debadutta Mishra:Department of Production Engineering, Veer Surendra University of Technology, Burla, 768018, India

Sanjib Jaypuria:Mechanical Engineering Department, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India

Abstract
In this article, we explore the issue concerning semiconductors half-space comprised of materials with varying thermal conductivity. The problem is within the framework of the generalized thermoelastic model under one thermal relaxation time. The half-boundary space's plane is considered to be traction free and is subjected to a thermal shock. The material is supposed to have a temperature-dependent thermal conductivity. The numerical solutions to the problem are achieved using the finite element approach. To find the analytical solution to the linear problem, the eigenvalue approach is used with the Laplace transform. Neglecting the new parameter allows for comparisons between numerical findings and analytical solutions. This facilitates an examination of the physical quantities in the numerical solutions, ensuring the accuracy of the proposed approach.

Key Words
finite element approach; semi-conductor material; thermal relaxation time; variable thermal conductivity

Address
Aatef D. Hobiny:Department of Mathematics, Faculty of Science, King Abdulaziz University, Saudi Arabia

Ibrahim A. Abbas:1)Department of Mathematics, Faculty of Science, King Abdulaziz University, Saudi Arabia
2)Department of mathematics, Faculty of Science, Sohag University, Egypt

C Alaa A. El-Bary:Basic and Applied Science Institute, Arab Academy for Science, Technology and Maritime Transport,
P.O. Box 1029, Alexandria 21532, Egypt

Abstract
In the current scenario, conventional concrete faces a substantial challenge in the modern era of the construction industry. Today's structures are massive, featuring innovative designs and strict time constraints. Conventional concrete does not provide the required compressive strength, tensile strength, flexural strength, toughness, and cracking resistance. As a result, most of engineers and professionals prefer to use ultra-high-performance concrete (UHPC), based on its wide advantages. Several advantages like mechanical and durability properties of UHPC provides dominant properties than the traditional concrete. Mix proportions of UHPC consists of higher powder content which provides maximum hydration and pozzolanic reaction, thereby contributing to the enhancement of the UHPC properties. Apart from that the nanomaterials provides the filler behavior, which will further improve the density. Enhanced density and mechanical properties lead to improved durability properties against water absorption and other typical chemicals. Nanomaterials are the most adopted materials for various applications, ranging in size from 0.1 nanometers to 100 nanometers. This article explores the effects of nanomaterial application in UHPC as a replacement for cementitious material or as an additive in the UHPC mix. The physical and durability properties modifications and improvements of UHPC, as well as negative effects, limitations, and shortcomings, are also analyzed.

Key Words
cementitious material; hydration and pozzolanic reaction; mechanical and durability properties; nanomaterials; Ultra-High-Performance concrete

Address
P. Jagadesh and Karthik Prabhu T:Department of Civil Engineering, Coimbatore Institute of Technology, Coimbatore, 641014, Tamil Nadu, India

Moutassim Charai:Green Energy Park (IRESEN, UM6P), km2 R206, 43150 Benguerir, Morocco

Ibrahim Y. Hakeem:Department of Civil Engineering, College of Engineering, Najran University, Najran, Saudi Arabia

Emrah Madenci:Department of Civil Engineering, Faculty of Engineering, Necmettin Erbakan University, Konya 42000, Turkey

Yasin Onuralp Ozkilic:1)Department of Civil Engineering, Faculty of Engineering, Necmettin Erbakan University, Konya 42000, Turkey
2)Department of Civil Engineering, Lebanese American University, Byblos, Lebanon

Abstract
Concrete filled rectangular steel tubular (CFRST) composite truss girder is composed of the CFRST truss and concrete slab. The failure mechanism of the girder was different under bending and shear failure modes. The bending and shear strength of the girder were investigated experimentally. The influences of composite effect and shear to span ratio on failure modes of the girder was studied. Results indicated that the top chord and the joint of the truss were strengthened by the composited effect. The failure modes of the specimens were changed from the joint on top chord to the bottom chord. However, the composite effect had limited effect on the failure modes of the girder with small shear to span ratio. The concrete slab and top chord can be regarded as the composite top chord. In this case, the axial force distribution of the girder was close to the pinjointed truss model. An approach of strength prediction was proposed which can take the composite effect and shear to span ratio into account. The approach gave accurate predictions on the strength of CFRST composite truss girder under different bending and shear failure modes.

Key Words
composite effect; composite truss girder; Concrete Filled Rectangular Steel Tube (CFRST); experiment; strength prediction

Address
Yinping Ma and Yongjian Liu:School of Civil Engineering, Chongqing University, Chongqing, 400045, China

Kun Wang:School of Highway, Chang'an University, Xi'an, 710064, China

Abstract
Stainless steels are commonly employed in engineering applications since they have superior properties such as low maintenance cost, and high temperature and corrosion resistance. These features allow them to be preferred in cylindrical shell structures as well. The behavior of a cylindrical shell structure made of stainless steel can be quite different from that made of carbon steel, as the material properties differ from each other. This paper deals with buckling behavior of axially loaded cylindrical shells made of stainless-steel. For this purpose, a combined experimental and numerical study was carried out. The experimental study comprised of testing of 18 cylindrical specimens. Following the experimental study, a numerical study was first conducted to validate test results. The comparisons show that finite element models provide good agreement with test results. Then, a numerical parametric study consisting of 450 models was performed to develop more generalized design recommendations for axially compressed cylindrical shell structures made of stainless steel. A simple formula was proposed for the practical design purposes. In other words, buckling strength curve equation is developed for three different fabrication quality.

Key Words
buckling; axial compression; cylindrical shells; resistance curve; stainless steel

Address
Ozer Zeybek:1)Department of Civil Engineering, Faculty of Engineering, Mugla Sitki Kocman University, Mugla, 48000, Turkey
2)Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47907, USA

Ali İhsan Celik:Tomarza Mustafa Akincioglu Vocational School, Department of Construction, Kayseri University, Kayseri, 38940, Turkey

Yasin Onuralp Ozkilic:1)Department of Civil Engineering, Faculty of Engineering, Necmettin Erbakan University, Konya 42000, Turkey
2)Department of Civil Engineering, Lebanese American University, Byblos, Lebanon
3)World Class Research Center Advanced Digital Technologies State Marine Technical University,
SaintPetersburg, 190121, Russian Federation


Abstract
Composite beams, two materials joined together, have become more common in structural engineering over the past few decades because they have better mechanical and structural properties. The shear connectors between their layers exhibit some deformability with finite stiffness, resulting in interfacial shear slip, a phenomenon known as partial shear interaction. Such a partial shear interaction contributes significantly to the composite beams. To provide precise predictions of the geometric nonlinear behavior shown by two-layered composite beams with interfacial shear slips, a robust analytical model has been developed that incorporates the influence of significant displacements. The application of a higher-order beam theory to the two material layers results in a third-order adjustment of the longitudinal displacement within each layer along the depth of the beam. Deformable shear connectors are employed at the interface to represent the partial shear interaction by means of a sequence of shear connectors that are evenly distributed throughout the beam's length. The Von-Karman theory of large deflection incorporates geometric nonlinearity into the governing equations, which are then solved analytically using the Navier solution technique. Suggested model exhibits a notable level of agreement with published findings, and numerical outputs derived from finite element (FE) model. Large displacement substantially reduces deflection, interfacial shear slip, and stress values. Geometric nonlinearity has a significant impact on beams with larger span-to-depth ratio and a greater degree of shear connector deformability. Potentially, the analytical model can accurately predict the geometric nonlinear responses of composite beams. The model has a high degree of generality, which might aid in the numerical solution of composite beams with varying configurations and shear criteria.

Key Words
analytical solution; composite beam; geometric nonlinearity; higher-order beam theory; partial shear interaction

Address
Jie Wen:School of Urban Construction, Zhejiang Shuren University, Hangzhou 310015, P.R. China

Abdul Hamid Sheikh:School of Civil, Environmental & Mining Engineering, The University of Adelaide, SA 5005, Australia

Md. Alhaz Uddin:Department of Civil Engineering, College of Engineering, Jouf University, Sakaka, Saudi Arabia

A.B.M.Saiful Islam:Department of Civil & Construction Engineering, College of Engineering, Imam Abdulrahman Bin Faisal University,
Dammam, 31451, Saudi Arabia

Md. Arifuzzaman:Department of Civil and Environmental Engineering, College of Engineering, King Faisal University, Al-Ahsa, 31982, Saudi Arabia

Abstract
This paper uses a new type of deformation theory to establish the free vibration and static buckling equations of nanoplates resting on two-parameter elastic foundations, in which the flexoelectric effect is taken into account. The proposed approach used in this work is not only simpler than other higher-order shear deformation theories but also does not need any shear correction coefficients to describe exactly the mechanical responses of structures. The reliability of the theory is verified by comparing the numerical results of this work with those of analytical solutions. The results show that the flexoelectric effect significantly changes the natural frequency and the critical buckling load of the nanoplate compared with the case of neglecting this effect, especially when the plate thickness changes and with some different boundary conditions. These are new results that have not been mentioned in any publications but are meaningful in engineering practice

Key Words
buckling; elastic foundation; finite element method; flexoelectric effect; nanoplates; vibration

Address
Bui Van Tuyen:Faculty of Mechanical Engineering, Thuyloi University, 175 Tay Son, Dong Da, Hanoi, Vietnam

Du Dinh Nguyen:Faculty of Civil Engineering, Lac Hong University, Dong Nai Province, Vietnam

Abdelouahed Tounsi:1)Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals,
31261 Dhahran, Eastern Province, Saudi Arabia
2)Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria
3)YFL (Yonsei Frontier Lab), Yonsei University, Seoul, Korea

Abstract
This paper uses a new type of deformation theory to establish the free vibration and static buckling equations of nanoplates resting on two-parameter elastic foundations, in which the flexoelectric effect is taken into account. The proposed approach used in this work is not only simpler than other higher-order shear deformation theories but also does not need any shear correction coefficients to describe exactly the mechanical responses of structures. The reliability of the theory is verified by comparing the numerical results of this work with those of analytical solutions. The results show that the flexoelectric effect significantly changes the natural frequency and the critical buckling load of the nanoplate compared with the case of neglecting this effect, especially when the plate thickness changes and with some different boundary conditions. These are new results that have not been mentioned in any publications but are meaningful in engineering practice

Key Words
buckling; elastic foundation; finite element method; flexoelectric effect; nanoplates; vibration

Address
Bui Van Tuyen:Faculty of Mechanical Engineering, Thuyloi University, 175 Tay Son, Dong Da, Hanoi, Vietnam

Du Dinh Nguyen:Faculty of Civil Engineering, Lac Hong University, Dong Nai Province, Vietnam

Abdelouahed Tounsi:1)Department of Civil and Environmental Engineering, King Fahd University of Petroleum & Minerals,
31261 Dhahran, Eastern Province, Saudi Arabia
2)Material and Hydrology Laboratory, University of Sidi Bel Abbes, Faculty of Technology, Civil Engineering Department, Algeria
3)YFL (Yonsei Frontier Lab), Yonsei University, Seoul, Korea

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