A realistic model for transverse shear stiffness prediction of composite corrugated-core sandwich elements

Artikel i vetenskaplig tidskrift, 2017

Several previous studies of the transverse shear stiffness of corrugated-core sandwich elements have demonstrated that the existing analytical formulations significantly overestimate this property, especially when these lightweight elements are made of composite sub-elements. Due to the recent widespread fabrication and use of composite sandwich elements in many fields of application, a more accurate and reliable formulation is needed. This paper deals with an accurate analytical model for predicting the transverse shear stiffness of composite sandwich elements with a structural corrugated core. The effect of the directional material properties of the sub-elements, including face sheets and core, as well as the effect of a low shear modulus in composite material constituents of the sub-elements, is taken into ac- count. It is shown that the transverse shear stiffness of corrugated web core elements is considerably lower than that predicted by the existing formulations. The present solution provides much more real- istic results, especially when the corrugated-core sandwich is made of composite constituents with low shear moduli. Different combinations of the main orthotropic material orientation of the faces and core are studied comparatively for different composite material choices corresponding to an innovative timber composite floor case. It is demonstrated that the planar direction of the main orthotropic material ori- entation of the core has a significant influence on transverse shear stiffness, whereas that of the faces is less important. Several finite element comparisons are made to ensure the reliability of the developed for- mulation. The importance of the disregarded shear deformation effects on the transverse shear stiffness component versus different geometrical parameters of the sandwich element is studied and discussed.