Model of multilayered materials for interface stresses estimation and validation by finite element calculations

TL;DR

This paper introduces and validates two multilayered material models (M4) for estimating interface stresses near free edges and microcracks in composites, using finite element analysis for validation.

Contribution

The paper develops and validates two simplified multilayered models (M4) for interface stress estimation in composite laminates, bridging 2D models with 3D FE results.

Findings

M4 models accurately predict interfacial stresses near free edges.

Energy analysis links simplified models to FE 3D stress fields.

Validation confirms models' effectiveness for microcrack and free-edge problems.

Abstract

The mechanical problem discussed in this paper focuses on the stress state estimation in a composite laminate in the vicinity of a free edge or microcracks. To calculate these stresses, we use two models called Multiparticle Models of Multilayered Materials (M4). The first one can be considered as a stacking sequence of Reissner-Mindlin plates (5 kinematic fields per layer), while the second is a membranar superposition (2 fields per layer plus a global one). These simplified models are able to provide finite values of interfacial stresses, even on the free edges of a structure. The current paper consists of validating the M4 by a finite element analysis through describing the stress fields in both a (0,90)s laminate in tension (free-edge problem) and a transversally microcracked (0,90)s laminate. A comparison of the various energy contributions helps yield a mechanical perspective: it appears possible to define an interply energy as well as a layer energy, these energies expressing the FE 3D reality.