New modeling and analysis methods for micro-plates

Download
index.pdf
2017
Aghazadeh, Reza
Show full item record
202
views
64
downloads
This study presents strain gradient elasticity based procedures for static bending, free vibration and buckling analyses of functionally graded rectangular micro-plates subjected to mechanical and thermal loadings. Mathematically the non-classical modified couple stress and classical elasticity theories are the two special cases of the new model. The methods developed allow taking into account spatial variations of length scale parameters of strain gradient elasticity and modified couple stress theory. Governing partial differential equations and boundary conditions are derived by following variational approaches and applying Hamilton’s principle. Displacement field is expressed in a unified way to produce numerical results in accordance with Kirchhoff, Mindlin, and third order shear deformation theories. All material properties, including the length scale parameters, are assumed to be functions of the plate thickness coordinate in the derivations. Developed equations are solved numerically by means of differential quadrature method. Proposed procedures are verified through comparisons made to the results available in the literature for certain limiting cases. Further numerical results are provided to illustrate the effects of material and geometric parameters upon static deflection, vibration frequency, and critical buckling load. Presented numerical results clearly illustrate size effect at micro-scale, impact of length scale parameter variations and influence of initial thermal stresses upon mechanical behavior of functionally graded rectangular micro-plates.
Elasticity., Bending., Vibration., Microtechnology., Buckling (Mechanics).
http://etd.lib.metu.edu.tr/upload/12621356/index.pdf
https://hdl.handle.net/11511/26948
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

Modelling of graded rectangular micro-plates with variable length scale parameters
Aghazadeh, Reza; Dağ, Serkan; Ciğeroğlu, Ender (2018-03-10)
This article presents strain gradient elasticity-based procedures for static bending, free vibration and buckling analyses of functionally graded rectangular micro-plates. The developed method allows consideration of smooth spatial variations of length scale parameters of strain gradient elasticity. Governing partial differential equations and boundary conditions are derived by following the variational approach and applying Hamilton's principle. Displacement field is expressed in a unified way to produce n...
Free vibration analysis of functionally graded rectangular nano-plates considering spatial variation of the nonlocal parameter
Alipour Ghassabi, Ata; Dağ, Serkan; Ciğeroğlu, Ender; Department of Mechanical Engineering (2017)
This study presents a new nonlocal elasticity based analysis method for free vibrations of functionally graded rectangular nano-plates. The method allows taking into account spatial variation of the nonlocal parameter. Governing partial differential equations and associated boundary conditions are derived by employing the variational approach and applying Hamilton’s principle. All required material properties are assumed to be functions of thickness coordinate in the derivations. Displacement field is expre...
Method for Dynamic Material Property Characterization of Soft-Tissue-Mimicking Isotropic Viscoelastic Materials Using Fractional Damping Models
Martin, Bryn A.; Kutluay, Umit; Yazıcıoğlu, Yiğit (ASTM International, 2013-09-01)
Characterization of the mechanical properties of human-tissue-mimicking silicone elastomers is important for producing accurate tissue models for experimentation. However, the viscoelastic and frequency-dependent material properties of elastomers are difficult to quantify. We present a material characterization technique for a silicone elastomer used to mimic human soft tissue based on generalized-Maxwell-type material models with and without fractional dissipating mechanisms. The silicone specimens were pr...
Development of electrochemical etch-stop techniques for integrated MEMS sensors
Yaşınok, Gözde Ceren; Akın, Tayfun; Department of Electrical and Electronics Engineering (2006)
This thesis presents the development of electrochemical etch-stop techniques (ECES) to achieve high precision 3-dimensional integrated MEMS sensors with wet anisotropic etching by applying proper voltages to various regions in silicon. The anisotropic etchant is selected as tetra methyl ammonium hydroxide, TMAH, considering its high silicon etch rate, selectivity towards SiO2, and CMOS compatibility, especially during front-side etching of the chip/wafer. A number of parameters affecting the etching are inv...
Exact solution of rotating FGM shaft problem in the elastoplastic state of stress
Akis, Tolga; Eraslan, Ahmet Nedim (Springer Science and Business Media LLC, 2007-10-01)
Plane strain analytical solutions to estimate purely elastic, partially plastic and fully plastic deformation behavior of rotating functionally graded (FGM) hollow shafts are presented. The modulus of elasticity of the shaft material is assumed to vary nonlinearly in the radial direction. Tresca's yield criterion and its associated flow rule are used to formulate three different plastic regions for an ideal plastic material. By considerina different material compositions as well as a wide range of bore radi...
Citation Formats
R. Aghazadeh, “New modeling and analysis methods for micro-plates,” Ph.D. - Doctoral Program, Middle East Technical University, 2017.
METU IIS - Integrated Information Service open@metu.edu.tr