A high accuracy four variable displacement model for thick-faced sandwich beams

Abstract

This paper presents a new four variable displacement model for thick-faced sandwich beams based on a layerwise formulation of transverse shear stress field. To account for structural characteristics of thick-faced sandwich beams, the transverse shear stress field is assumed to follow quadratic and uniform distributions in face layers and soft core respectively. A novel comprehensive approach is first proposed to determine the relation between stress variables of quadratic terms in shear stress expressions of the top and bottom layers, and thus the number of independent variables in shear stress expressions is reduced from three to two. According to the simplified stress expressions, the in-plane displacement field is determined, and the final displacement expression with four unknowns is further achieved by imposing interlaminar continuity conditions. The present model can accurately describe zigzag effects and provide ideal transverse shear stress results for sandwich beams. Then, finite element solutions for static and dynamic analyses of sandwich beams are presented. Moreover, complex eigenvalue problems for free vibration analysis of viscoelastic sandwich beams are studied, and an iterative procedure is presented for determining modal results of sandwich beams with frequency-dependent viscoelastic core. Lastly, the accuracy of the present model for static and dynamic analyses of sandwich beams is well validated by numerical cases.