scholarly journals Size effect on pull-in behavior of electrostatically actuated microbeams based on a modified couple stress theory

2013 ◽  
Vol 37 (12-13) ◽  
pp. 7481-7488 ◽  
Author(s):  
Shengli Kong
2015 ◽  
Vol 15 (07) ◽  
pp. 1540025 ◽  
Author(s):  
Li-Na Liang ◽  
Liao-Liang Ke ◽  
Yue-Sheng Wang ◽  
Jie Yang ◽  
Sritawat Kitipornchai

This paper is concerned with the flexural vibration of an atomic force microscope (AFM) cantilever. The cantilever problem is formulated on the basis of the modified couple stress theory and the Timoshenko beam theory. The modified couple stress theory is a nonclassical continuum theory that includes one additional material parameter to describe the size effect. By using the Hamilton's principle, the governing equation of motion and the boundary conditions are derived for the AFM cantilevers. The equation is solved using the differential quadrature method for the natural frequencies and mode shapes. The effects of the sample surface contact stiffness, length scale parameter and location of the sensor tip on the flexural vibration characteristics of AFM cantilevers are discussed. Results show that the size effect on the frequency is significant when the thickness of the microcantilever has a similar value to the material length scale parameter.


2013 ◽  
Vol 300-301 ◽  
pp. 889-892
Author(s):  
Sheng Li Kong

For the deformation problem of an electrostatically actuated cantilever micro-beam, size effect on pull-in behaviors of the micro-beams have been studied based on modified couple stress theory. The approximate analytical solutions to the pull-in voltage and pull-in displacement of the micro-beam are derived by using the Rayleigh-Ritz method. The results show that the normalized pull-in voltage of the cantilever micro-beam is size-dependent and the normalized pull-in displacement of the micro-beam is size independence.


2021 ◽  
Vol 76 (5) ◽  
pp. 427-434
Author(s):  
Duygu Atcı

Abstract In this study, free vibration analysis of nanobeams under various non-ideal supports have presented. Size effect of nanobeams has applied by utilizing modified couple stress theory. Hamilton’s principle has been used to derive the equation of motion. Governing equation has subjected to non-ideal boundary conditions which are modeled as linear functions including an introduced weighting factor (k). Obtained numerical results have verified by comparing with the published results. Results show that fundamental resonance frequencies of non-ideal clamped nanobeams are significantly decreased when it is compared to ideal supports. However, non-ideal simply supports creates a minor increase effect on fundamental frequencies with respect to clamped ones. Also, nano-size effect has investigated for non-ideal supports. It has found that, the smaller cross-sectional size of nanobeam causes increasing effect of non-ideal supports on fundamental frequencies.


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