Abstract
The bending response of microstructure-dependent miniature beam-like structures is examined within the theoretical framework of the modified couple stress theory. Predicated on a planar assumed displacement field, and adopting the small-strain, linearly elastic and Timoshenko’s shear deformable beam theory assumptions, the equilibrium equations governing the bending response of these structures are established via the variational method. Finite element solutions of the model are sought. The finite element solutions are implemented in the R programming language and then employed to illustrate the influence of size-effect on the bending response of microscale beams.
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- 1.
In the words of AEH Love in Theoretical Mechanics, such models facilitate “the description of motion of material bodies”.
- 2.
The words size-effect and small-scale effect are used interchangeably in this text. In the context of this book, they are used to describe the dependency of the response of small-scale structures on their size.
- 3.
A scalar quantity typically measured in energy per volume.
- 4.
In two-dimensional approximations, the field variable (such as displacement or stress field) depends on two coordinates, and the boundary conditions are imposed on a line. Conversely, in one-dimensional approximations, the field variable is a function of one coordinate and the boundary conditions are imposed on points.
- 5.
The displacement-strain relations are obtained with the assumption that the axial, shear and curvature strains along with the rotation of the beam are small in comparison to unity.
- 6.
We have replaced \(\mu\), originally in Eq. (2.10), by G.
- 7.
This is to remedy the fact that the shear stress has been taken to be independent of z, and hence uniform across the thickness.
- 8.
The total work done is also a scalar quantity like the strain energy.
- 9.
From the knowledge that \(\gamma = \left( { - \phi + \frac{dw}{d\xi }} \right) = c.\)
- 10.
This is true for static problems. For dynamic problems, more elements are necessary to obtain accurate results.
- 11.
Please note that page 140 of the reference contains other results, here we have only done the computation for the case of \(L = 12\,h,\,l = 1/3h\).
- 12.
As expected the value of the slope at node 2 is approximately zero.
- 13.
Please note that page 140 of the reference contains other results, here we have only done the computation for the case of \(L = 12\,h,\,l = 1/3h\).
References
J.F. Doyle, Static and Dynamic Analysis of Structures: With an Emphasis on Mechanics and Computer Matrix Methods (Springer, Netherlands, 1991)
M.H. Kahrobaiyan, M. Asghari, M.T. Ahmadian, A strain gradient Timoshenko beam element: Application to MEMS. Acta Mech. 226, 505–525 (2015)
R.A. Coutu Jr., P.E. Kladitis, L. Starman, J.R. Reid, A comparison of micro-switch analytic, finite element, and experimental results. Sens. Actuators, A 115, 252–258 (2004)
V. Kaajakari, Practical MEMS: Small Gear Pub. (2009)
S. Khakalo, V. Balobanov, J. Niiranen. Modelling size-dependent bending, buckling and vibrations of 2D triangular lattices by strain gradient elasticity models: Applications to sandwich beams and auxetics. Int. J. Eng. Sci. 127, 33–52 (2018)
B.R. Goncalves, A. Karttunen, J. Romanoff, J. Reddy, Buckling and free vibration of shear-flexible sandwich beams using a couple-stress-based finite element. Compos. Struct. 165, 233–241 (2017)
A.T. Karttunen, J. Romanoff, J. Reddy, Exact microstructure-dependent Timoshenko beam element. Int. J. Mech. Sci. 111, 35–42 (2016)
C.L. Dym, I.H. Shames, Solid mechanics: A variational approach, Augmented edn. (Springer, New York, 2013)
R. Mindlin, H. Tiersten, Effects of couple-stresses in linear elasticity. Arch. Ration. Mech. Anal. 11, 415–448 (1962)
S. Wulfinghoff, E. Bayerschen, T. Böhlke, Micromechanical simulation of the Hall-Petch effect with a crystal gradient theory including a grain boundary yield criterion. PAMM 13, 15–18 (2013)
W.B. Anderson, R.S. Lakes, Size effects due to Cosserat elasticity and surface damage in closed-cell polymethacrylimide foam. J. Mater. Sci. 29, 6413–6419 (1994)
R. Lakes, Size effects and micromechanics of a porous solid. J. Mater. Sci. 18, 2572–2580 (1983)
P.R. Onck, E.W. Andrews, L.J. Gibson, Size effects in ductile cellular solids. Part I: modeling. Int. J. Mech. Sci. 43, 681–699 (2001)
P. Giovine, L. Margheriti, M.P. Speciale, On wave propagation in porous media with strain gradient effects. Comput. Math. Appl. 55, 307–318 (2008)
A. Kelly, Precipitation hardening (Pergamon Press, 1963)
R. Ebeling, M.F. Ashby, Dispersion hardening of copper single crystals. Philos. Mag. 13, 805–834 (1966)
M.F. Ashby, The deformation of plastically non-homogeneous materials. Philos. Mag. 21, 399–424 (1970)
J.W. Hutchinson, Plasticity at the micron scale. Int. J. Solids Struct. 37, 225–238 (2000)
D.C.C. Lam, A.C.M. Chong, Indentation model and strain gradient plasticity law for glassy polymers. J. Mater. Res. 14, 3784–3788 (1999)
H. Askes, E.C. Aifantis, Gradient elasticity in statics and dynamics: An overview of formulations, length scale identification procedures, finite element implementations and new results. Int. J. Solids Struct. 48, 1962–1990 (2011)
J. Dyszlewicz, Micropolar Theory of Elasticity (Springer, Heidelberg, 2004)
H.-T. Thai, T.P. Vo, T.-K. Nguyen, S.-E. Kim, A review of continuum mechanics models for size-dependent analysis of beams and plates. Compos. Struct. 177, 196–219 (2017)
S. Khakalo, J. Niiranen, Form II of Mindlin’s second strain gradient theory of elasticity with a simplification: For materials and structures from nano- to macro-scales. Eur. J. Mech. A/Solids 71, 292–319 (2018)
W. Voigt, Theoretische studien über die elasticitätsverhältnisse der krystalle: Königliche Gesellschaft der Wissenschaften zu Göttingen (1887)
E. Cosserat, F. Cosserat, Théorie des corps déformables (1909)
R.D. Mindlin, H.F. Tiersten, Effects of couple-stresses in linear elasticity. Arch. Ration. Mech. Anal. 11, 415–448 (1962)
R.A. Toupin, Elastic materials with couple-stresses. Arch. Ration. Mech. Anal. 11, 385–414 (1962)
W. Koiter, Couple-stress in the theory of elasticity, in Proceedings of the K. Ned. Akad. Wet (1964), pp. 17–44
A.C. Eringen, A unified theory of thermomechanical materials. Int. J. Eng. Sci. 4, 179–202 (1966)
A.C. Eringen, E.S. Suhubi, Nonlinear theory of simple micro-elastic solids—I. Int. J. Eng. Sci. 2, 189–203 (1964)
R.D. Mindlin, Micro-structure in linear elasticity. Arch. Ration. Mech. Anal. 16, 51–78 (1964)
R.D. Mindlin, N.N. Eshel, On first strain-gradient theories in linear elasticity. Int. J. Solids Struct. 4, 109–124 (1968)
R.D. Mindlin, Second gradient of strain and surface-tension in linear elasticity. Int. J. Solids Struct. 1, 417–438 (1965)
K.B. Mustapha, D. Ruan, Size-dependent axial dynamics of magnetically-sensitive strain gradient microbars with end attachments. Int. J. Mech. Sci. 94–95, 96–110 (2015)
K.B. Mustapha, B.T. Wong, Torsional frequency analyses of microtubules with end attachments. ZAMM-J. Appl. Math. Mech./Zeitschrift für Angewandte Mathematik und Mechanik 96, 824–842 (2016)
D.C.C. Lam, F. Yang, A.C.M. Chong, J. Wang, P. Tong, Experiments and theory in strain gradient elasticity. J. Mech. Phys. Solids 51, 1477–1508 (2003)
F. Yang, A.C.M. Chong, D.C.C. Lam, P. Tong, Couple stress based strain gradient theory for elasticity. Int. J. Solids Struct. 39, 2731–2743 (2002)
J.N. Reddy, Microstructure-dependent couple stress theories of functionally graded beams. J. Mech. Phys. Solids 59, 2382–2399 (2011)
H.M. Ma, X.L. Gao, J.N. Reddy, A microstructure-dependent Timoshenko beam model based on a modified couple stress theory. J. Mech. Phys. Solids 56, 3379–3391 (2008)
A.C.M. Chong, F. Yang, D.C.C. Lam, P. Tong, Torsion and bending of micron-scaled structures. J. Mater. Res. 16, 1052–1058 (2001)
A.H. Nayfeh, P.F. Pai, Linear and Nonlinear Structural Mechanics (Wiley, 2008)
J.R. Barber, Elasticity (Springer, Heidelberg, 2002)
E.B. Magrab, Vibrations of Elastic Systems: With Applications to MEMS and NEMS, vol 184 (Springer Science & Business Media, 2012)
M.H. Kahrobaiyan, M. Asghari, M.T. Ahmadian, A Timoshenko beam element based on the modified couple stress theory. Int. J. Mech. Sci. 79, 75–83 (2014)
I. Babuska, B.A. Szabo, I.N. Katz, The p-version of the finite element method. SIAM J. Numer. Anal. 18, 515–545 (1981)
T. Apel, J.M. Melenk, Interpolation and quasi-Interpolation in h- and hp-version finite element spaces. Encyclopedia of Computational Mechanics, 2nd edn. (2017), pp. 1–33
A.M. Dehrouyeh-Semnani, A. Bahrami, On size-dependent Timoshenko beam element based on modified couple stress theory. Int. J. Eng. Sci. 107, 134–148 (2016)
A. Arbind, J. Reddy, Nonlinear analysis of functionally graded microstructure-dependent beams. Compos. Struct. 98, 272–281 (2013)
C. Liebold, W.H. Müller, Comparison of gradient elasticity models for the bending of micromaterials. Comput. Mater. Sci. 116, 52–61 (2016)
Z. Li, Y. He, J. Lei, S. Guo, D. Liu, L. Wang, A standard experimental method for determining the material length scale based on modified couple stress theory. Int. J. Mech. Sci. 141, 198–205 (2018)
R. Narayanaswami, H. Adelman, Inclusion of transverse shear deformation in finite element displacement formulations. AIAA J. 12, 1613–1614 (1974)
A. Öchsner, Computational Statics and Dynamics: An Introduction Based on the Finite Element Method (Springer, Singapore, 2016)
T.B. Jones, N.G. Nenadic, Electromechanics and MEMS (Cambridge University Press, 2013)
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Mustapha, K.B. (2019). Bending of Microstructure-Dependent MicroBeams and Finite Element Implementations with R. In: R for Finite Element Analyses of Size-dependent Microscale Structures. SpringerBriefs in Applied Sciences and Technology(). Springer, Singapore. https://doi.org/10.1007/978-981-13-7014-4_2
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DOI: https://doi.org/10.1007/978-981-13-7014-4_2
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