A comment on “Static and dynamic analysis of micro beams based on strain gradient elasticity theory” [Int. J. Eng. Sci. 47 (2009) 487–498]

This article Comments on the highly cited work concerning static and dynamic analysis of microbeams based on modified strain gradient elasticity theory [Shengli Kong, Shenjie Zhou, Zhifeng Nie, Kai Wang(2009). Int. j. Eng. Sci., 47, 478-498]. They assumed that three length scale parameters in modified strain gradient elasticity theory are equal (i.e. ℓ0 = ℓ1 = ℓ2 = ℓS) and the modified strain gradient length scale parameter is equal to the modified couple stress one (i.e. ℓS = ℓ). The second assumption resulting in modified strain gradient elasticity theory does not validate the experimental data and, moreover, the difference between the modified strain gradient elasticity results and the modified couple stress ones is overestimated.