• Dottavio, Michele
• Polit, Olivier
• Le, Thi Huyen Cham
• Cara, Girolamo Di

Abstract

The Finite Element implementation is discussed for the first time of a recently proposed variable kinematics modeling approach for composite plates, the Sublaminate Generalized Unified Formulation (SGUF). The plate model is defined upon subdividing the composite stack into "sublaminates", each composed of an arbitrary number of adjacent plies. Classical displacement-based as well as mixed models are considered, the latter ones allowing independent approximations to be formulated for transverse stresses and displacements (RMVT models).Each variable (displacement and transverse stress component) in each sublaminate can be attributed an arbitrary approximation across the thickness: ESL or LW descriptions can be used in conjunction with an arbitrary order of polynomial expansion. Murakami’s ZigZag Function can be introduced in a displacement field with ESL description for allowing the C0 behaviour of transverse strains at ply interfaces.Linear 4-node as well as quadratic 8-node locking-free Finite Elements (FE) are constructed adopting special interpolation schemes for the transverse shear strain fields. The transverse stress variables can be retained (mixed FEM) or condensed out at element level (hybrid FEM). The resulting stiffness matrices are shown to be full rank and can cope with distorted element shapes.These variable kinematics plate models and the corresponding displacement-based, mixed and hybrid FE, are all implemented as User Elements into the commercial software Abaqus. A dedicated Python plugin guides the user to the proper model definition, indicating all parameters required to identify the plate FE. Preliminary results are shown to highlight the robustness and accuracy of the proposed elements. The SGUF approach is particularly attractive for modelling single- or multi-core sandwich panels with composite skins.

Topics

• impedance spectroscopy
• composite