Experimental Testing and Analytical Modeling of Asymmetric End-Notched Flexure Tests on Glass-Fiber Metal Laminates

Konrad Dadej,Paolo Sebastiano Valvo,Jarosław Bieniaś

doi:10.3390/met10010056

Konrad Dadej, Paolo Sebastiano Valvo + Show 1 more

Open Access

https://doi.org/10.3390/met10010056

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Journal: Metals	Publication Date: Dec 28, 2019
Citations: 15	License type: CC BY 4.0

Affiliation: Lublin University of Technology, University of Pisa

Abstract

An experimental campaign on glass-fiber/aluminum laminated specimens was conducted to assess the interlaminar fracture toughness of the metal/composite interface. Asymmetric end-notched flexure tests were conducted on specimens with different fiber orientation angles. The tests were also modeled by using two different analytical solutions: a rigid interface model and an elastic interface model. Experimental results and theoretical predictions for the specimen compliance and energy release rate are compared and discussed.

Highlights

Fiber metal laminates (FMLs) are hybrid composite materials made of adhesively bonded layers of metal alloys and fiber-reinforced laminates
We present the results of asymmetric end-notched flexure (AENF) tests on multidirectional glass fiber-reinforced polymer/aluminum (GFRP/Al) specimens and show how these can be interpreted based on both the rigid [16] and elastic [18] interface models
According to the ASTM standard [26], the possible initial nonlinearity due to fixture must be excluded from regression analysis and the specimen compliance should be calculated from the linear part of the curves

Summary

Introduction

Fiber metal laminates (FMLs) are hybrid composite materials made of adhesively bonded layers of metal alloys and fiber-reinforced laminates. Despite the very good damage tolerance features of FMLs, fatigue and fracture phenomena may still strongly limit the service life of FML components [9]. Delamination—i.e., interfacial fracture between the constituting layers—is a major failure mode for FMLs, as well as for composite laminates in general [10]. Experimental assessment and theoretical modeling of fatigue and fracture phenomena in FMLs are complicated by the inhomogeneous internal structure of this class of hybrid composite materials. Structural models have to consider the strong elastic couplings arising—e.g., between bending and extension, bending and twisting, etc.—because of the general asymmetric stacking sequences [11]. Delamination analysis should account for the mixed-mode fracture conditions typical of asymmetrically located delamination cracks [12]

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