An approximate model to describe the size effects of spherical contact tests, based on a modified couple stress elasticity

2021 ◽  
Author(s):  
Chao Peng ◽  
Fanlin Zeng ◽  
Bin Yuan ◽  
Youshan Wang
Keyword(s):  
Size Effects ◽  
Couple Stress ◽  
Approximate Model ◽  
Spherical Contact ◽  
Couple Stress Elasticity ◽  
Modified Couple Stress

Size effects in two-dimensional layered materials modeled by couple stress elasticity

2021 ◽  
Author(s):  
Wipavee Wongviboonsin ◽  
Panos A. Gourgiotis ◽  
Chung Nguyen Van ◽  
Suchart Limkatanyu ◽  
Jaroon Rungamornrat
Keyword(s):  
Size Effects ◽  
Couple Stress ◽  
Layered Materials ◽  
Two Dimensional ◽  
Couple Stress Elasticity

scholarly journals A Modified Couple Stress Elasticity for Non-Uniform Composite Laminated Beams Based on the Ritz Formulation

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1404 ◽  
Author(s):  
Farajollah Zare Jouneghani ◽  
Hamidraza Babamoradi ◽  
Rossana Dimitri ◽  
Francesco Tornabene
Keyword(s):  
Boundary Conditions ◽  
Couple Stress ◽  
Scale Parameter ◽  
Laminated Composite ◽  
Length Scale Parameter ◽  
Smart Devices ◽  
Small Scale ◽  
Length Scale ◽  
Couple Stress Elasticity ◽  
Modified Couple Stress

Due to the large application of tapered beams in smart devices, such as scanning tunneling microscopes (STM), nano/micro electromechanical systems (NEMS/MEMS), atomic force microscopes (AFM), as well as in military aircraft applications, this study deals with the vibration behavior of laminated composite non-uniform nanobeams subjected to different boundary conditions. The micro-structural size-dependent free vibration response of composite laminated Euler–Bernoulli beams is here analyzed based on a modified couple stress elasticity, which accounts for the presence of a length scale parameter. The governing equations and boundary conditions of the problem are developed using the Hamilton’s principle, and solved by means of the Rayleigh–Ritz method. The accuracy and stability of the proposed formulation is checked through a convergence and comparative study with respect to the available literature. A large parametric study is conducted to investigate the effect of the length-scale parameter, non-uniformity parameter, size dimension and boundary conditions on the natural frequencies of laminated composite tapered beams, as useful for design and optimization purposes of small-scale devices, due to their structural tailoring capabilities, damage tolerance, and their potential for creating reduction in weight.

Formulation for Static Behavior of the Viscoelastic Euler-Bernoulli Micro-Beam Based on the Modified Couple Stress Theory

2012 ◽  
Author(s):  
E. Taati ◽  
M. Nikfar ◽  
M. T. Ahmadian
Keyword(s):  
Size Effects ◽  
Couple Stress ◽  
Couple Stress Theory ◽  
Closed Form Solution ◽  
Modified Couple Stress Theory ◽  
Form Solution ◽  
Equilibrium Equations ◽  
Stress Theory ◽  
Modified Couple Stress ◽  
Micro Structures

In this work an analytical solution is presented for a viscoelastic micro-beam based on the modified couple stress theory which is a non-classical theory in continuum mechanics. The modified couple stress theory has the ability to consider small size effects in micro-structures. It is strongly emphasized that without considering these effects in such structures the solution will be wrong and not suitable for designing systems in micro-scales. In this study correspondence principle is used for deriving constitutive equations for viscoelastic material based on the modified couple stress theory. Governing equilibrium equations are obtained by considering an element of micro-beam. Closed-form solution for the static deflection of simply supported micro-beam is presented. Numerical results show that when the size of system is near the length scale parameter, the classical response will intensely be deviated from the correct solution observed in laboratories contrary to the modified couple stress which reflects the size effects.

Mixed Natural Neighbor Galerkin Method for 3D Couple-Stress Elasticity

2010 ◽  
Vol 37-38 ◽  
pp. 667-670
Author(s):  
Kai Wang ◽  
Shen Jie Zhou ◽  
Zhi Feng Nie
Keyword(s):  
Galerkin Method ◽  
Size Effects ◽  
Couple Stress ◽  
Degrees Of Freedom ◽  
Characteristic Length ◽  
Three Dimensional ◽  
Discrete Equations ◽  
Natural Neighbor ◽  
Couple Stress Elasticity ◽  
Geometrical Constraints

Based on the constrained variational principle, the mixed multi-variable natural neighbor Galerkin method for couple-stress elasticity is proposed for three-dimensional problems. The displacements and micro-rotations are taken to be independent nodal degrees of freedom, and the geometrical constraints between them are enforced through Lagrange multipliers. The C0-continuous non-Sibsonain interpolation is used to obtain the discrete equations. The proposed method is tested by the numerical example and the results show that strong size effects are observed when the length of deformation field and the characteristic length of the material are comparable.

FGM micro/nano-plates within modified couple stress elasticity

2020 ◽  
Vol 245 ◽  
pp. 112294
Author(s):  
V. Sladek ◽  
J. Sladek ◽  
M. Repka ◽  
L. Sator
Keyword(s):  
Couple Stress ◽  
Couple Stress Elasticity ◽  
Modified Couple Stress

First-order shear deformation theory for orthotropic doubly-curved shells based on a modified couple stress elasticity

2018 ◽  
Vol 73 ◽  
pp. 129-147 ◽  
Author(s):  
Farajollah Zare Jouneghani ◽  
Payam Mohammadi Dashtaki ◽  
Rossana Dimitri ◽  
Michele Bacciocchi ◽  
Francesco Tornabene
Keyword(s):  
Shear Deformation ◽  
Couple Stress ◽  
Deformation Theory ◽  
Shear Deformation Theory ◽  
First Order ◽  
Doubly Curved Shells ◽  
Couple Stress Elasticity ◽  
Modified Couple Stress ◽  
Doubly Curved
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