Article
Engineering, Multidisciplinary
Xiaoxia Ma, Keivan Kiani
Summary: By utilizing nonlocal continuum mechanics, the buckling characteristics of nanobeams are analyzed. Nonlocal beam models and deformation equations are established and a Galerkin-based meshless approach is used to evaluate the critical buckling response. For the first time, the spatial nonlocal buckling behavior of nanobeams is examined and the significant role of nonlocality and shear deformation is discussed.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2023)
Article
Mathematics, Applied
Rolfssoren Krausshar
Summary: This paper extends the study of Szego kernels in the setting of octonionic monogenic functions and establishes explicit formulas for them. The kernels can be expressed in terms of cosecant and cotangent functions.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2021)
Article
Engineering, Multidisciplinary
Guozhe Shen, Yang Xia, Weidong Li, Guojun Zheng, Ping Hu
Summary: Peridynamics is a nonlocal theory that can handle easily discontinuities such as cracks, even though it is computationally more expensive. The study introduces new PD beam and shell models based on micro-beam bond and Timoshenko beam theory, with interpolation method used for describing various deformations and strain energy densities. The high precision of PD beam and shell models is proven through simulation results.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2021)
Article
Mechanics
Damjan Banic, Goran Turkalj, Domagoj Lanc
Summary: This paper presents a shear deformable beam model for the nonlinear stability analysis of composite beam-type structures that considers the effects of restrained warping, large rotation, and shear deformation. The incremental equilibrium equations are derived using an updated Lagrangian formulation and Hooke's law is assumed to be valid. The accuracy and reliability of the proposed numerical model are verified on benchmark examples, showing that it is a shear locking-free model.
COMPOSITE STRUCTURES
(2023)
Article
Computer Science, Interdisciplinary Applications
Alaa A. Abdelrahman, Norhan A. Mohamed, Mohamed A. Eltaher
Summary: This article presents a comprehensive model and analytical solution to investigate the static bending behavior of regularly squared cutout perforated thin/thick nanobeams, considering the coupled effect of microstructure and surface energy. The article develops equilibrium equations and closed-form solutions for non-classical bending profiles and rotational displacement, taking into account the effects of couple stress and surface stress. The results show that both couple stress and surface stress significantly affect the bending behavior of perforated beam structures.
ENGINEERING WITH COMPUTERS
(2022)
Article
Multidisciplinary Sciences
B. Gultekin Sinir
Summary: This study investigates the post-buckling behavior of a transverse functionally graded beam using Euler-Bernoulli beam theory and shear deformable beam theories. The mathematical models of these theories are derived using the vector approach. It is found that the mathematical models of shear deformable beam theories can be obtained using the vector approach.
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING
(2023)
Article
Engineering, Civil
Andrea Monserrat Lopez, Miguel Fernanez Ruiz, Pedro Fco Miguel Sosa
Summary: This paper investigates the shear strength of reinforced concrete beams with and without shear reinforcement based on various potential shear-transfer actions. A comprehensive experimental program was conducted to represent realistic conditions. The results showed consistent agreement between experimental and calculated shear strength, indicating the dominant role of shear-transfer actions at shear failure.
ENGINEERING STRUCTURES
(2021)
Article
Chemistry, Analytical
Yuhang Chen, Maomao Zhang, Yaxuan Su, Zhidong Zhou
Summary: The flexoelectric effect has a significant impact on the electro-mechanical coupling of micro-nano devices, particularly in functionally graded beams. This study investigates the mechanical and electrical properties of such beams under various electrical boundary conditions, highlighting the influences of flexoelectric effect, piezoelectric effect, and gradient distribution on their performance. The results show that nonuniform piezoelectricity and polarization direction play a leading role in induced electric potential, and flexoelectric effect dominates as beam thickness decreases.
Article
Engineering, Multidisciplinary
Quoc-Hoa Pham, Van Ke Tran, Trung Thanh Tran, Phu-Cuong Nguyen, Parviz Malekzadeh
Summary: A finite element modeling combined with the strain gradient theory (SGT) and the refined higher-order shear deformation beam theory is developed to study the dynamic instability of magnetically embedded functionally graded porous (FGP) nanobeams. The influences of various parameters on the dynamic instability of nanobeams are studied in detail, revealing their effects on the behavior of nanobeams.
ALEXANDRIA ENGINEERING JOURNAL
(2022)
Article
Engineering, Civil
Margaritis Tonidis, Akanshu Sharma
Summary: This paper investigates the seismic performance of non-seismically designed reinforced concrete exterior and interior beam-column joints, focusing on the influence of transverse beams and slabs. The study reveals that transverse beams increase joint shear strength and slabs affect the flexural behavior of beams in the sub-assemblies.
ENGINEERING STRUCTURES
(2021)
Article
Mechanics
Koutoati Kouami, Mohri Foudil, Daya El Mostafa, Carrera Erasmo
Summary: A beam finite element model is proposed for static and free vibration analyses of FGM sandwich beams with viscoelastic nonlinear material behavior. Different viscoelastic frequency-dependent laws, Timoshenko 1st order, and Reddy's higher order shear models are used. The stiffness matrix is nonlinear and frequency dependent. The study shows that beam behavior is sensitive to the loss factor, and damping properties are nonlinearly dependent on the power law index. Boundary conditions affect vibration modes.
COMPOSITE STRUCTURES
(2021)
Article
Engineering, Civil
Amal Wahbi, Duc Toan Pham, Ghazi Hassen, Denis Garnier, Patrick de Buhan
Summary: The upper bound kinematic approach is used for the design of RC beams subjected to various loadings, optimizing strength conditions through a simple virtual collapse mechanism.
ENGINEERING STRUCTURES
(2021)
Article
Engineering, Civil
Arash Sahraei, Payam Pezeshky, Siriwut Sasibut, Feng Rong, Magdi Mohareb
Summary: This study develops a theory for the static analysis of thin-walled members with general asymmetric cross-sections, capturing global and through-thickness warping, as well as shear deformation effects. Closed-form solutions are formulated for beams with asymmetric, monosymmetric, point symmetric, and doubly symmetric cross-sections, and comparisons with previous theories verify the validity of the present theory and quantify the effects of shear deformation and warping.
THIN-WALLED STRUCTURES
(2021)
Article
Engineering, Mechanical
Vladislav S. Sorokin, Jon Juel Thomsen, Marie Brons
Summary: The paper investigates the coupling between longitudinal and transverse vibrations of tensioned Euler-Bernoulli beams, considering two types of excitations. A simple approach is proposed to predict and describe this coupling phenomenon, and a series of experiments are conducted to validate the theoretical predictions.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Engineering, Multidisciplinary
Sadegh Ghamsari Esfahani, Saeid Sarrami-Foroushani, Mojtaba Azhari
Summary: This paper introduces a novel reproducing kernel particle finite strip method for analyzing static, mechanical, and thermal buckling, as well as free vibration of rectangular functionally graded plates. The method combines reproducing kernel particle method with finite strip method, and has been validated with various examples.
APPLIED MATHEMATICAL MODELLING
(2021)
Article
Engineering, Mechanical
Keivan Kiani, Soroush Soltani
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2020)
Article
Engineering, Multidisciplinary
Yuan Yuan, Kuo Xu, Keivan Kiani
APPLIED MATHEMATICAL MODELLING
(2020)
Article
Mechanics
Keivan Kiani, Krzysztof Kamil Zur
Summary: In this study, suitable surface energy-nonlocal-integral and differential models were reported for investigating the mechanical behavior of a nanosystem consisting of double parallel nanorods with defects. By evaluating nonlocal-surface energy-based modes and implementing the Galerkin method, the capabilities of capturing the natural frequencies of the defected nanosystem were revealed. The roles of nonlocality, surface energy, nanorod characteristics, defect properties, and elastic interface layer constant on free vibration were explained.
COMPOSITE STRUCTURES
(2021)
Article
Mechanics
Keivan Kiani, Mahdi Efazati
Summary: This study focuses on the movements of three-dimensionally moving pretensioned wire-like nanostructures in a vacuum under static loads, considering nonlocality and surface energy. It presents governing equations for purely linear static and dynamic states, investigates the static deformations and potential divergence instability, and analyzes the free vibration response and dynamic instability under various types of motion through the Galerkin method.
ARCHIVE OF APPLIED MECHANICS
(2021)
Article
Engineering, Mechanical
Fan Fan, Keivan Kiani
Summary: This paper introduces a novel analytical solution for vibrational scrutiny of multi-layered composite nanomembranes, incorporating nonlocality and surface effects, using the isodeflection curve approach. The newly developed equations are ordinary differential equations, depending on a single parameter, which can be applied to various shapes of multi-layered nanomembranes.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2021)
Article
Physics, Multidisciplinary
Banghua Xie, Keivan Kiani
Summary: The transverse vibration of mislocated double-parallel nanobeams under an inclined magnetic field is important, influencing both inter-structure forces and the system's stiffness. Using RKPM and AMA methods can successfully solve for nonlocal frequencies and analyze the effects of magnetic field strength, inclination, mislocation, and nonlocality on dominant frequencies.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Engineering, Multidisciplinary
Keivan Kiani
Summary: This study focuses on the twisting vibrations of coaxial-composite nanowires with damages and imperfect interface, using nonlocal models and reproducing kernel particle method for solving the problem. The results show that factors such as the location and intensity of damages, nonlocality, surface energy, imperfect interface parameter, and geometry significantly influence the twisting behavior of the nanostructure.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Engineering, Multidisciplinary
Guilian Yu, Keivan Kiani, Mojtaba Roshan
Summary: This paper investigates the nonlocal transverse vibrations of vertically aligned single-layered membranes made from single-walled carbon nanotubes (SWCNTs) for the transportation of nanoparticles. The nanotubes are modeled using classical and shear deformable beams, while the moving nanoparticles are treated as rigid-in-contact particles with different velocities that take into account their weight force, inertia, and lags. The nonlocal equations of motion are derived considering the intertube van der Waals (vdW) forces and then solved systematically for elasto-dynamic fields. The effects of inertia, shear deformation, nonlocality, velocities, and lags of moving nanoparticles on the dynamic response of the nanosystem are explained in detail for two types of nanosystem decorations. The most critical case among various loadings, lags, and velocities of moving nanoparticles is introduced and discussed.
APPLIED MATHEMATICAL MODELLING
(2022)
Article
Engineering, Multidisciplinary
Jiafeng Chu, Qingjian Jiang, Keivan Kiani
Summary: This paper investigates the potential instability and vibrations of triple-nanowire systems carrying electrical current using the surface elasticity theory. The surface energy-based equations of motion are developed and the natural frequencies are evaluated using a meshless approach. The effects of various factors on the dominant frequencies are discussed.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Engineering, Multidisciplinary
Boyuan Mu, Keivan Kiani
Summary: This study investigates the spatial buckling behavior of nanowires under axial force and twisting moment, and establishes the governing equations solved by the reproducing kernel particle method (RKPM). A reasonably good match between the results attained by the RKPM and those of the assumed modes approach (AMA) is achieved. The unstable conditions of the nanowires under severe axial forces and twisting moments are identified for the first time, and the critical roles of shear deformation and surface energy are methodically displayed and discussed.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Engineering, Multidisciplinary
Min Li, Chenxia Wang, Keivan Kiani
Summary: The first objective of this study is to formulate the problem appropriately under the surface elasticity theory. Spatial equations of motion are established using various beam models and then analyzed via a meshless technique. The interactional role of axial force and torque on the fundamental frequency is discussed. The influences of the NW's aspect ratio and interactions with the elastic matrix on the dominant frequencies are systematically displayed. Critical values of the slenderness ratio and NW's radius are graphically illustrated, showing the crucial roles of shear deformation and surface effect on free vibration at these critical levels.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2023)
Article
Engineering, Multidisciplinary
Xiaoxia Ma, Keivan Kiani
Summary: By utilizing nonlocal continuum mechanics, the buckling characteristics of nanobeams are analyzed. Nonlocal beam models and deformation equations are established and a Galerkin-based meshless approach is used to evaluate the critical buckling response. For the first time, the spatial nonlocal buckling behavior of nanobeams is examined and the significant role of nonlocality and shear deformation is discussed.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2023)
Article
Multidisciplinary Sciences
Xiaoxia Ma, Mojtaba Roshan, Keivan Kiani, Ali Nikkhoo
Summary: In this study, the researchers investigated the dynamic deflection of a nanostructure embedded in a vibrating medium used for moving nano-objects. They derived the governing equations and developed analytical and numerical solutions to capture the nonlocal behavior. The results showed the importance of considering the inertial effect and shear effect in such systems.
Article
Environmental Sciences
Mingrui Li, Jin Hu, Pengzhen Liu, Jiayu Chen
Summary: As a new industry based on the traditional financial system and enhanced by emerging technologies, digital finance plays a significant role in the development of microenterprises. By analyzing the Digital Inclusive Finance Index of Peking University from 2011 to 2018, this study focused on inventory optimization and incremental innovation mechanisms. The research findings demonstrate that digital financing greatly contributes to the high-quality development of enterprises. Furthermore, it was revealed that digital finance effectively corrects mismatches in scale, attribute, phase, and industry, thus addressing financing constraints and promoting deleveraging of enterprises in the economic development process. However, there are still limitations for companies with high financing constraints and leverage, and financial regulation can enhance the economic performance of digital finance. These findings provide empirical evidence and policy insights for promoting the development of digital finance, deepening the supply-side structural reform of finance, serving the real economy more effectively, and achieving high-quality economic development.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Physics, Multidisciplinary
Bo Xu, Keivan Kiani
Summary: This study investigates the nonlinear axial and lateral vibrations of nanoscaled beams under bidirectional support excitations. By considering various factors such as von-Karman terms, small-scale effect, and surface energy, the study derives and solves the nonlinear equations of motion for the nanobeam, while analyzing the effects of excitation parameters, geometry, and nonlocality on the dynamic response. The importance of nonlinear analysis in capturing the realistic dynamic response of the bi-directionally excited nanobeam is emphasized.
Article
Engineering, Mechanical
Rosaria Del Toro, Maria Laura De Bellis, Marcello Vasta, Andrea Bacigalupo
Summary: This article presents a multifield asymptotic homogenization scheme for analyzing Bloch wave propagation in non-standard thermoelastic periodic materials. The proposed method derives microscale field equations, solves recursive differential problems within the unit cell, establishes a down-scaling relation, and obtains average field equations. The effectiveness of this approach is validated by comparing dispersion curves with those from the Floquet-Bloch theory.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2024)
Article
Engineering, Mechanical
Yue Bao, Zhengcheng Yao, Yue Zhang, Xueman Hu, Xiandong Liu, Yingchun Shan, Tian He
Summary: This paper proposes a novel triple-gradient phononic acoustic black hole (ABH) beam that strategically manipulates multiple gradients to enhance its performance. The study reveals that the ABH effect is not solely brought about by the thickness gradient, but also extends to the power-law gradients in density and modulus. The synergistic development of three different gradient effects leads to more pronounced and broader bandgaps in PCs.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2024)
Article
Engineering, Mechanical
Matthias Ryser, Jason Steffen, Bekim Berisha, Markus Bambach
Summary: This study investigates the feasibility of replacing complex experiments with multiple simpler ones to determine the anisotropic yielding behavior of sheet metal. The results show that parameter identifiability and accuracy can be achieved by combining multiple specimen geometries and orientations, enhancing the understanding of the yield behavior.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2024)
Article
Engineering, Mechanical
Wenjun Li, Pengfei Zhang, Siyong Yang, Shenling Cai, Kai Feng
Summary: This study presents a novel two-dimensional non-contact platform based on Near-field Acoustic Levitation (NFAL), which can realize both one-dimensional and two-dimensional transportation. Numerical and experimental results prove the feasibility and ease of this method.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2024)
Article
Engineering, Mechanical
Shuo Liu, Lu Che, Guodong Fang, Jun Liang
Summary: This study presents a novel lamina conjugated bond-based peridynamic (BB-PD) model that overcomes the limitations of material properties and is applicable to composite laminates with different stacking sequences. The accuracy and applicability of the model are validated through simulations of elastic deformation and progressive damage behavior, providing an explanation of the damage modes and failure mechanisms of laminated composite materials subjected to uniaxial loading.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2024)
Article
Engineering, Mechanical
Omar El-Khatib, S. Kumar, Wesley J. Cantwell, Andreas Schiffer
Summary: Sandwich-structured honeycombs (SSHCs) are hierarchical structures with enhanced mass-specific properties. A model capable of predicting the elastic properties of hexagonal SSHCs is presented, showing superior in-plane elastic and shear moduli compared to traditional honeycombs, while the out-of-plane shear moduli are reduced.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2024)
Article
Engineering, Mechanical
Zhi-Jian Li, Hong-Liang Dai, Yuan Yao, Jing-Ling Liu
Summary: This paper proposes a process-performance prediction model for estimating the yield strength and ultimate tensile strength of metallic parts fabricated by powder bed fusion additive manufacturing. The effect of main process variables on the mechanical performance of printed metallic parts is analyzed and the results can serve as a guideline for improvement. The accuracy of the proposed model is validated by comparison with literature.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2024)
Article
Engineering, Mechanical
Saman A. Bapir, Kawa M. A. Manmi, Rostam K. Saeed, Abdolrahman Dadvand
Summary: This study numerically investigates the behavior of an ultrasonically driven gas bubble between two parallel rigid circular walls with a cylindrical micro-indentation in one wall. The primary objective is to determine the conditions that facilitate the removal of particulate contamination from the indentation using the bubble jet. The study found that the bubble jet can effectively remove contamination from the indentation for certain ranges of indentation diameter, but becomes less effective for larger indentation diameters.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2024)
Article
Engineering, Mechanical
E. Polyzos, E. Vereroudakis, S. Malefaki, D. Vlassopoulos, D. Van Hemelrijck, L. Pyl
Summary: This research investigates the elastic and damage characteristics of individual composite beads used in 3D printed composites. A new analytical probabilistic progressive damage model (PPDM) is introduced to capture the elastic and damage attributes of these beads. Experimental results show strong agreement with the model in terms of elastic behavior and ultimate strength and strain.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2024)
