Article
Engineering, Multidisciplinary
Jun Lei, Caixia Shao, Leiting Dong
Summary: In this paper, size-dependent elastodynamic plane problems are studied using a consistent couple-stress theory (C-CST). The equations are transformed to frequency domain using the Laplace transform method, and numerically solved using a collocation method with the treatment of singular integrals. Time-dependent solutions are obtained by the Durbin's method for the inverse Laplace transform, showing good agreement with analytical or numerical solutions.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2023)
Review
Computer Science, Interdisciplinary Applications
Shengli Kong
Summary: The article discusses the size-dependent material deformation behaviors of certain metals and polymers at micro scale experiments and how the modified couple stress theory (MCST) can capture these size dependences. It reviews available size-dependent models for micro-beam and micro-plate based on MCST, and establishes relevant mechanical models and solutions for static bending, vibration, buckling, and pull-in instability of representative micro-structures. The results indicate significant size effects on the mechanical properties of micro-structures, suggesting potential further research on size-dependent behaviors.
ARCHIVES OF COMPUTATIONAL METHODS IN ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Yan Shang, Yu-Hao Mao, Song Cen, Chen-Feng Li
Summary: A new displacement-based Trefftz plate element is developed for size-dependent bending analysis of thin plate structures, incorporating the modified couple stress theory and generalized conforming theory, with satisfactory numerical performance.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2021)
Article
Mechanics
Xuan Ye, Hansong Ma, Xiaoming Liu, Yueguang Wei
Summary: In this study, the thermal bending of bilayer microbeams was investigated by modifying the couple stress and Timoshenko beam theories to consider the size and shear effects. The results showed that the size effect on beam stiffness is significant when the beam height is on the order of equivalent length scale (leq). Moreover, considering the transverse shear effect indicated that the lateral deflection of the Timoshenko beam depends on the ratio L/h: as L/h increases, the tip deflection increases and converges to the classical solution. Specifically, for a Timoshenko beam with h/leq = 15, the change in deflection can reach 44.6% when L/h is increased from 5 to 25.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2023)
Article
Engineering, Aerospace
Xuan-Bach Bui, Trung-Kien Nguyen, Armagan Karamanli, Thuc P. Vo
Summary: This paper examines the static and vibration analysis of functionally graded sandwich thin-walled microbeams using the modified couple stress theory. The analysis results show that the deflections and natural frequencies of the microbeams are greatly influenced by the material distribution and size parameters.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Physics, Multidisciplinary
Hamid M. Sedighi, Ahmed E. Abouelregal, S. Ali Faghidian
Summary: This study investigates the deficiency of the modified couple stress theory in accurately describing the material response of continua with nano-structural features. By reassessing the flexure mechanics of nano-scale beams within this theory, physically motivated constitutive laws are introduced and the effects of symmetric rotation gradients and transverse shear deformation are examined. Additionally, closed-form analytical formulae for the elastic modulus of Carbon Nanotubes are derived and the applicability of the modified couple stress beam model in accurately capturing size-effects in nano-materials is rigorously examined.
Article
Engineering, Multidisciplinary
Sayed Mohamad Mirfatah, Mohammad Amin Shahmohammadi, Hamzeh Salehipour, Omer Civalek
Summary: This work aims to evaluate the dynamic stability of micro-shell panels enriched by nanocomposites using an analytical approach. The modified couple stress theory is utilized to account for the size effects on the mechanical behavior of the micro-shell panels. The fundamental equations, based on the first-order shear deformation theory, are solved using the Galerkin method to obtain a closed-form solution for evaluating the dynamic stability of the proposed micro-shell panels. Comparative studies and a parametric study are conducted to validate the accuracy of the proposed method and investigate the effects of the material length scale parameter on the dynamic stability of the micro-shell panels.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2022)
Article
Engineering, Multidisciplinary
Jae-Hoon Choi, Wael Zaki, Gi-Dong Sim
Summary: This article develops a constitutive model for shape memory alloys considering size effects based on a thermodynamic framework. Couple stress elastoplasticity is used to simulate size effects. Three material length scale parameters are introduced as additional material properties for elastic size effect and crystal structure transformation. The model is formulated with three-dimensional equations and can be applied to analyze structures with arbitrary shapes using the finite element method. Two benchmark problems are solved using the model, showing a significant increase in structural stiffness as the size decreases. The developed size-dependent constitutive model is expected to be used for the analysis of micro/nano-scale structures composed of shape memory alloys.
APPLIED MATHEMATICAL MODELLING
(2023)
Article
Engineering, Electrical & Electronic
Oscar Zi Shao Ong, Mergen H. Ghayesh, Shahid Hussain
Summary: This article investigates the vibration behavior of a double-microbeam system using an assumed-mode expansion technique and finite-element verifications. The study reveals that increasing the couple-stress-tensor-related parameter or stiffness coefficient of the elastic connection can enhance the natural frequencies of the system, and the free vibration characteristics vary under different boundary conditions.
MICROSYSTEM TECHNOLOGIES-MICRO-AND NANOSYSTEMS-INFORMATION STORAGE AND PROCESSING SYSTEMS
(2021)
Article
Computer Science, Interdisciplinary Applications
Yu-Hao Mao, Yan Shang, Song Cen, Chen-Feng Li
Summary: A novel nonconforming 3-node triangular plate element is proposed within the modified couple stress elasticity to simulate the size-dependent static and dynamic bending behaviors of thin microplates and study the effects of micro-inertia. The element exhibits satisfying numerical accuracy and captures size dependences effectively, with higher order modes being more influenced by micro-inertia.
ENGINEERING WITH COMPUTERS
(2023)
Article
Engineering, Multidisciplinary
Jun Lei, Pengsheng Ding, Chuanzeng Zhang
Summary: This study develops a 2D boundary element method based on a consistent couple stress elasticity theory to solve boundary value problems in couple stress elastic materials. Various numerical and semi-analytical techniques are utilized to enhance the accuracy of calculations.
ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS
(2021)
Article
Materials Science, Multidisciplinary
Busra Uzun, Mustafa Ozgur Yayh
Summary: In this study, the size-dependent static and free torsional vibration responses of functionally graded porous nanotubes are investigated for the first time using specific mathematical methods. The emphasis is on exploring the effects of various factors such as boundary conditions, material distribution, etc.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Mechanics
Pham Hong Cong, Do Van Thom, Doan Hong Duc
Summary: This paper investigates the crack propagation behavior of plane strain micro-plates using the modified couple stress theory and the phase-field theory. A phase-field formulation for fracture mechanics based on the framework of the modified couple stress is established for the first time. The results highlight the difference in mechanical properties during crack propagation when considering size-effect based on modified couple stress. This work is important for scientists studying the fracture development process in microstructures.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Computer Science, Interdisciplinary Applications
Jae-Hoon Choi, Byung-Chai Lee, Gi-Dong Sim
Summary: A new mixed tetrahedral element based on the Lagrange multiplier is developed for the modified couple stress theory in this paper. By condensing out the Lagrange multipliers and introducing higher-order rotation modes, the total number of degrees of freedom is greatly reduced, maximizing computational efficiency.
COMPUTERS & STRUCTURES
(2021)
Article
Chemistry, Physical
Feixiang Tang, Siyu He, Shaonan Shi, Shun Xue, Fang Dong, Sheng Liu
Summary: The purpose of this paper is to study the bending, buckling, and vibration of micro-thin plates by considering the micro-scale effects. The results show that the scale effect increases the equivalent stiffness of the thin plate, leading to a decrease in deflection, a larger critical buckling load, and an increase in natural frequency, but does not affect the buckling topography. The findings of this research may contribute to the design of micro-scale devices such as MEMSs/NEMSs.
Article
Engineering, Multidisciplinary
M. Rahaeifard, M. T. Ahmadian, K. Firoozbakhsh
APPLIED MATHEMATICAL MODELLING
(2015)
Article
Engineering, Multidisciplinary
M. Rahaeifard
COMPOSITES PART B-ENGINEERING
(2015)
Article
Engineering, Multidisciplinary
M. Rahaeifard, M. T. Ahmadian
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2015)
Article
Mechanics
M. Mojahedi, M. Rahaeifard
INTERNATIONAL JOURNAL OF APPLIED MECHANICS
(2015)
Article
Engineering, Multidisciplinary
M. Rahaeifard
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2016)
Article
Engineering, Multidisciplinary
M. Mojahedi, M. Rahaeifard
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2016)
Article
Engineering, Biomedical
E. Yassini, M. Mirzaei, A. Alimi, M. Rahaeifard
JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS
(2016)
Article
Engineering, Multidisciplinary
M. Rahaeifard, M. Mojahedi
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2017)
Article
Engineering, Civil
M. Rahaeifard, M. Mojahedi
INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS
(2017)
Article
Engineering, Civil
A. Karimzadeh, M. T. Ahmadian, K. Firoozbakhsh, M. Rahaeifard
INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS
(2017)
Article
Thermodynamics
S. Zandekarimi, B. Asadi, M. Rahaeifard
JOURNAL OF THERMAL STRESSES
(2018)
Article
Engineering, Multidisciplinary
M. H. Kahrobaiyan, M. Rahaeifard, M. T. Ahmadian
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2014)
Article
Engineering, Multidisciplinary
M. Rahaeifard, M. T. Ahmadian, K. Firoozbakhsh
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2014)
Article
Engineering, Multidisciplinary
A. Karimzadeh, M. T. Ahmadian, M. Rahaeifard