Remarks on ‘‘A simple first-order shear deformation theory for laminated composite plates’’

Kurzfassung

Regarding Huu-Tai Thai and Dong-Ho Choi: A simple first-order shear deformation theory for laminated composite plates. Composite Structures 106 (2013) 754–763. In the above mentioned paper a first-order shear deformation theory is proposed. Splitting up the transverse deflection w into a bending and a shear contribution (w = wb + ws) allows to reduce the number of functional degrees of freedom from five to four. As correctly emphasized by the authors this reduces the computational cost. However, it should not be left unmentioned that this procedure has some drawbacks also. Using wb to model the Kirchhoff normal rotation leaves only one functional degree of freedom, ws, to specify the shear rotations. Depending on the difference in transverse shear stiffness in x- and y-direction, these shear rotations can be very different. As shown in [1] the deviations of the resulting in-plane displacements can deviate drastically from the 3D elasticity solution. Also the difference in transverse deflection between FSDT and the proposed procedure pointed out in Fig. 5 of the paper, especially for low fiber angles Θ, can be traced back to this effect. Reference [1] Rohwer K. Application of higher order theories to the bending analysis of layered composite plates. Int J Solids Struct 1992;29(1):105–19.