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An Innovative Finite Element Geometric Modeling of Single-Layer Multi-Bead WAAMed Part

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2383-2401页

作者： Xiangman Zhou Jingping Qin Zichuan Fu Min Wang Youlu Yuan Junjian Fu Haiou Zhang Seyed Reza Elmi Hosseini College of Mechanical and Power Engineering China Three Gorges UniversityYichang443002China School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan430074China School of Metallurgy and Materials Engineering Iran University of Science and TechnologyNarmakIran

Finite element (FE) coupled thermal-mechanical analysis is widely used to predict the deformation and residualstress of wire arc additive manufacturing (WAAM) parts. In this study, an innovative single-layermulti-bead profilegeometric modeling method through the isosceles trapezoid function is proposed to build the FE model of theWAAMprocess. Firstly, a straight-line model for overlapping beads based on the parabola function was establishedto calculate the optimal center distance. Then, the isosceles trapezoid-based profile was employed to replace theparabola profiles of the parabola-based overlapping model to establish an innovative isosceles trapezoid-basedmulti-bead overlapping geometric model. The rationality of the isosceles trapezoid-based overlapping model wasconfirmed by comparing the geometric deviation and the heat dissipation performance index of the two overlappingmodels. In addition, the FE-coupled thermal-mechanical analysis, as well as a comparative experiment of thesingle-layer eight-bead deposition process show that the simulation results of the above two models agree with theexperimental results. At the same time, the proposed isosceles trapezoid-based overlappingmodels are all straightlineprofiles, which can be divided into high-quality FE elements. It can improve the modeling efficiency andshorten the simulation calculation time. The innovative modeling method proposed in this study can provide anefficient and high-precision geometricmodelingmethod forWAAMpart FE coupled thermal-mechanical analysis.

关键词： WAAM FE coupled thermal-mechanical analysis the isosceles trapezoid-based model residual stress

Traveling wave solutions of the nonlinear Gilson-Pickering equation in crystal lattice theory

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Journal of Ocean Engineering and Science 2024年第1期9卷 40-49页

作者： A.T.Nguyen O.Nikan Z.Avazzadeh Division of Applied Mathematics Science and Technology Advanced InstituteVan Lang UniversityHo Chi Minh CityVietnam Faculty of Technology Van Lang UniversityHo Chi Minh CityVietnam School of Mathematics Iran University of Science and TechnologyNarmakTehranIran Department of Applied Mathematics Xi’an Jiaotong-Liverpool UniversitySuzhou 215123China

This paper focuses on obtaining the traveling wave solutions of the nonlinear Gilson-Pickering equa-tion(GPE),which describes the prorogation of waves in crystal lattice theory and plasma *** solution of the GPE is approximated via the finite difference technique and the localized meshless radial basis function generated finite *** association of the technique results in a meshless approach that does not require linearizing the nonlinear *** the first step,the PDE is converted to a system of nonlinear ODEs with the help of the radial *** the second step,a high-order ODE solver is adopted to discretize the nonlinear ODE *** global collocation techniques pose a considerable computationl burden due to the calculation of the dense algebraic *** proposed method approx-imates differential operators over the local support domain,leading to sparse differentiation matrices and decreasing the computational *** results and comparisons are provided to confirm the efficiency and accuracy of the method.

关键词： Nonlinear Gilson–Pickering equation Soliton wave solutions Meshless technique RBF LRBF-FD Optimal shape parameter

AGGREGATE SPECIAL FUNCTIONS TO APPROXIMATE PERMUTING TRI-HOMOMORPHISMS AND PERMUTING TRI-DERIVATIONS ASSOCIATED WITH A TRI-ADDITIVEψ-FUNCTIONAL INEQUALITY IN BANACH ALGEBRAS

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Acta Mathematica Scientia 2024年第1期44卷 311-338页

作者： Safoura Rezaei ADERYANI Azam AHADI Reza SAADATI Hari M.SRIVASTAVA School of Mathematics Iran University of Science and TechnologyNarmakTehranIran Department of Mathematics and Statistics Universtity of VictoriaVictoriaCanada Department of Medical Research China Medical University HospitalChina Medical UniversityTaichung40402China Department of Mathematics and Informatics Azerbaijan University71 Jeyhun Hajibeyli StreetAZ1007BakuAzerbaijan Section of Mathematics International TelematicUniversity UninettunoI-00186RomeItaly

In this paper,we define a new class of control functions through aggregate special *** class of control functions help us to stabilize and approximate a tri-additiveψ-functional inequality to get a better estimation for permuting tri-homomorphisms and permuting tri-derivations in unital C*-algebras and Banach algebras by the vector-valued alternative fixed point theorem.

关键词： permuting tri-homomorphism in Banach algebra permuting tri-derivation on C*-algebra fixed point theorem Ulam-Hyers-Rassias stability aggregate special functions tri-additiveψ-functional inequality

Secrecy Outage Probability Minimization in Wireless-Powered Communications Using an Improved Biogeography-Based Optimization-Inspired Recurrent Neural Network

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Computers, Materials & Continua 2024年第3期78卷 3971-3991页

作者： Mohammad Mehdi Sharifi Nevisi Elnaz Bashir Diego Martín Seyedkian Rezvanjou Farzaneh Shoushtari Ehsan Ghafourian Department of Industrial Engineering Iran University of Science and TechnologyNarmakTehran16846-13114Iran Department of Computer Science Iowa State UniversityAmesIowaIA50011USA ETSI de Telecomunicación Universidad Politécnica de MadridMadrid28040Spain Department of Engineering California State University East BayHaywardCalifornia94542USA Department of Industrial Engineering Bu-Ali Sina UniversityHamedan65178-38695Iran

This paper focuses on wireless-powered communication systems,which are increasingly relevant in the Internet of Things(IoT)due to their ability to extend the operational lifetime of devices with limited *** main contribution of the paper is a novel approach to minimize the secrecy outage probability(SOP)in these *** SOP is crucial for maintaining the confidentiality and integrity of data,especially in situations where the transmission of sensitive data is *** proposed method harnesses the power of an improved biogeography-based optimization(IBBO)to effectively train a recurrent neural network(RNN).The proposed IBBO introduces an innovative migration *** core advantage of IBBO lies in its adeptness at maintaining equilibrium between exploration and *** is accomplished by integrating tactics such as advancing towards a random habitat,adopting the crossover operator from genetic algorithms(GA),and utilizing the global best(Gbest)operator from particle swarm optimization(PSO)into the IBBO *** IBBO demonstrates its efficacy by enabling the RNN to optimize the system parameters,resulting in significant outage probability *** comprehensive simulations,we showcase the superiority of the IBBO-RNN over existing approaches,highlighting its capability to achieve remarkable gains in SOP *** paper compares nine methods for predicting outage probability in wireless-powered *** IBBO-RNN achieved the highest accuracy rate of 98.92%,showing a significant performance *** contrast,the standard RNN recorded lower accuracy rates of 91.27%.The IBBO-RNN maintains lower SOP values across the entire signal-to-noise ratio(SNR)spectrum tested,suggesting that the method is highly effective at optimizing system parameters for improved secrecy even at lower SNRs.

关键词： Wireless-powered communications secrecy outage probability improved biogeography-based optimization recurrent neural network

Enhancing Hyper-Spectral Image Classification with Reinforcement Learning and Advanced Multi-Objective Binary Grey Wolf Optimization

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Computers, Materials & Continua 2024年第6期79卷 3469-3493页

作者： Mehrdad Shoeibi Mohammad Mehdi Sharifi Nevisi Reza Salehi Diego Martín Zahra Halimi Sahba Baniasadi TheWPI Business School Worcester Polytechnic InstituteWorcesterMassachusetts01609-2280USA Department of Industrial Engineering Iran University of Science and TechnologyNarmakTehran16846-13114Iran ETSI de Telecomunicación Universidad Politécnica de MadridAv.Complutense 30Madrid28040Spain Department of Civil and Environmental Engineering University of MarylandCollege ParkMaryland20742USA Department of Industrial Engineering College of EngineeringUniversity of HoustonHoustonTexas77204USA

Hyperspectral(HS)image classification plays a crucial role in numerous areas including remote sensing(RS),agriculture,and the monitoring of the *** band selection in HS images is crucial for improving the efficiency and accuracy of image *** process involves selecting the most informative spectral bands,which leads to a reduction in data *** on these key bands also enhances the accuracy of classification algorithms,as redundant or irrelevant bands,which can introduce noise and lower model performance,are *** this paper,we propose an approach for HS image classification using deep Q learning(DQL)and a novel multi-objective binary grey wolf optimizer(MOBGWO).We investigate the MOBGWO for optimal band selection to further enhance the accuracy of HS image *** the suggested MOBGWO,a new sigmoid function is introduced as a transfer function to modify the wolves’*** primary objective of this classification is to reduce the number of bands while maximizing classification *** evaluate the effectiveness of our approach,we conducted experiments on publicly available HS image datasets,including Pavia University,Washington Mall,and Indian Pines *** compared the performance of our proposed method with several state-of-the-art deep learning(DL)and machine learning(ML)algorithms,including long short-term memory(LSTM),deep neural network(DNN),recurrent neural network(RNN),support vector machine(SVM),and random forest(RF).Our experimental results demonstrate that the Hybrid MOBGWO-DQL significantly improves classification accuracy compared to traditional optimization and DL ***-DQL shows greater accuracy in classifying most categories in both datasets *** the Indian Pine dataset,the MOBGWO-DQL architecture achieved a kappa coefficient(KC)of 97.68%and an overall accuracy(OA)of 94.32%.This was accompanied by the lowest root mean square error(RMSE)of 0.94,indicating very precise

关键词： Hyperspectral image classification reinforcement learning multi-objective binary grey wolf optimizer band selection

脆性材料I型(张开)-断裂韧性测定的PFC2D和试验研究:一种新方法

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Acta Mechanica Sinica 2024年第2期40卷 116-130页

作者：付金伟 Hadi Haeri Joseph FLabuz Vahab Sarfarazi Pouyan Ebneabbasi MRM Aliha Hamid Reza Karimi Shirin Jahanmiri Mohammad Fatehi Marji School of Civil Engineering and Transportation North China University of Water Resources and Electric PowerZhengzhou450046China Department of Mining Engineering Higher Education Complex of ZarandShahid Bahonar University of KermanKermanIran Department of Civil Environmentaland Geo-EngineeringUniversity of MinnesotaMinneapolis55455USA Department of Mining Engineering Hamedan University of TechnologyHamedanIran Research Scholar Civil Engineering DepartmentIslamic Azad UniversityHamedanIran Welding and Joining Research Center School of Industrial EngineeringIran University of Science and TechnologyNarmakTehranIran School of Civil Engineering Iran University of Science and Technology(IUST)NarmakTehranIran Department of Mine Exploitation Engineering Faculty of Mining and MetallurgyInstitute of EngineeringYazd UniversityYazdIran

在本文研究中,通过利用优势边缘缺口盘型(END)试样,确定了石灰石的断裂韧性,提出了一种新的石灰石归一化相应力、高相变的计算方法.采用柔性有限元法(FEM)对试样的I型(张开)-断裂韧性进行了精确计算,并得到了相应实用公式.在试验中,还... 详细信息

在本文研究中,通过利用优势边缘缺口盘型(END)试样,确定了石灰石的断裂韧性,提出了一种新的石灰石归一化相应力、高相变的计算方法.采用柔性有限元法(FEM)对试样的I型(张开)-断裂韧性进行了精确计算,并得到了相应实用公式.在试验中,还使用含缺口巴西圆盘(NBD)试件,测试了END程序的准确性.为了在数值上重现这些测试并验证断裂韧性测量的正确性,还对END测试进行了离散元分析.数值模拟结果与实验结果吻合良好.然而,END研究所确定的韧性水平低于NBD测试规定的韧性水平,这是因为END石灰石样品中的缺口具有均匀的拉伸应力分布.

关键词：断裂韧性脆性材料实用公式拉伸应力巴西圆盘离散元分析相变归一化

MODAL ACOUSTIC IMPEDANCE FORCE ON A SPHERICAL SOURCE NEAR A RIGID INTERFACE

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Acta Mechanica Sinica 2003年第1期19卷 33-39页

作者： SeyyedM.HASHEMINEJAD DepartmentofMechanicalEngineering IranuniversityofScienceandTechnologyNarmakTehran16844Iran

The modal acoustic radiation load on a spherical surface undergoing angularly periodic axisymmetric harmonic vibrations while immersed in an acoustic halfspace with a rigid (infinite impedance) planar boundary is analyzed in an exact fashion using the classical technique of separation of variables. The formulation utilizes the appropriate wave field expansions, the classical method of images and the appropriate translational addition theorem to simulate the relevant boundary conditions for the given configuration. The associated acoustic field quantities such as the modal impedance matrix and the modal acoustic radiation force acting on the spherical surface are determined. The analytical results are illustrated with a numerical example in which the spherical surface, excited in vibrational modes of various orders, is immersed near an impervious rigid wall. The presented solution could eventually be used to validate those obtained by numerical approximation techniques.

关键词： radiation impedance acoustic halfspace spherical source

Relationship between Oxygen Chemical Potential and Steel Cleanliness

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Journal of Iron and Steel Research International 2005年第5期12卷 28-33,62页

作者： Mansour Soltanieh Yousef Payandeh Iran University of Science and Technology Narmak Tehran 16844 IranIran University of Science and Technology Narmak Tehran 16844 Iran

To investigate inclusion formation in each step during steel making process, several samples were taken in different steps of the production of steel at Mobarakeh Steel Co of Esfahan to measure the oxygen chemical potential of the molten steel in each stage. The chemical compositions of the inclusions in samples were investigated by scanning electron microscope. The chemical composition of the slag was analyzed. With the use of thermodnamic calculations and chemical analysis of the melt, at the working temperature, the relationship between dissolved oxygen and other elements were determined. Finally, it was found that there is a close relationship between inclusions formed in each step with the oxygen partial pressure.

关键词： inclusion steel cleanliness oxygen chemical potential

In vitro corrosion-fatigue behavior of biodegradable Mg/HA composite in simulated body fluid

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Journal of Magnesium and Alloys 2021年第6期9卷 2169-2184页

作者： E.Ghazizadeh A.H.Jabbari M.Sedighi School of Mechanical Engineering Iran University of Science and TechnologyNarmakTehranIran

Magnesium and its composites as biodegradable materials offer especial capabilities to be used as bio-absorbable ***,their poor corrosion and fatigue properties in the physiological environment can restrict their *** this study,corrosion-fatigue tests have been performed on the extruded magnesium and magnesium/hydroxyapatite(Mg/HA)composites in a high cycle *** produce the composites,pure magnesium was reinforced by 2.5 wt.%and 5 wt.%of hydroxyapatite submicron particles using an electromagneticmechanical stirring method and hot extrusion *** experimental density measurement exhibits that the porosity increases in the extruded samples with more hydroxyapatite *** investigate the corrosion and corrosion-fatigue behavior of the specimens,simulated body fluid(SBF)was used during in vitro *** results of the potentiodynamic polarization corrosion test show that the composite with 2.5 wt.%of hydroxyapatite(Mg/2.5 wt.%HA)and the pure magnesium specimen exhibit the highest and the lowest corrosion resistance,*** the elemental mapping analysis of the corroded samples,this behavior could be due to the formation of strong phosphorus-calcium based layers on the composite *** results obtained from the mechanical tests indicate that Mg/5 wt.%HA offered the highest tensile and compressive yield strengths,as well as the most promising high cycle fatigue *** the corrosionfatigue test,the simultaneous effects of fatigue and corrosion damages led to a similar corrosion-fatigue behavior in both *** fracture surfaces of the corrosion-fatigue samples suggest that the cracks are initiated in the corroded regions of the samples surface,which reduces the crack initiation step and subsequently decreases the fatigue *** comparison with the pure magnesium,both composites exhibit more promising corrosion and corrosion-fatigue behaviors with a significant fatigue life improvement in the ph

关键词： Magnesium Magnesium/Hydroxyapatite composite Corrosion Biodegradation High cycle fatigue Corrosion-fatigue