Experimental studies and numerical simulations are performed to investigate the structural response of adhesively bonded CFRP cylindrical splice-joint panels subjected to axial compression. Splicer joints used in aerospace composite structures need to sustain the design ultimate loads in the presence of flaws due to manufacturing (debonds), in order to demonstrate compliance with flightworthiness. CFRP cylindrical splice-joint specimens with and without debonds are subjected to compression load. Experimental data reveals that the load-carrying capacity of splicer joint decreases in the presence of debonds. Numerical simulations are carried out in line with experimental observations using finite element analysis. Good correlations with experimental results are obtained both in terms of buckling load capacity and load-displacement responses. Non-destructive methods, pulsed thermography and acoustic emission, are employed to detect and monitor the response of debond respectively. Parametric studies are also performed using finite element analysis to assess the influence of bi-directional loading and the effect of the physical gap provided between basic panels in the splicer joints. © 2015 Elsevier Ltd.

Arunachalakasi Arockiarajan

Department of Applied Mechanics

R. Palaninathan

Acoustic emission testing

Acoustic emissions

Axial compression

Buckling

Debonding

Nondestructive examination

Numerical models

ADHESIVELY BONDED

AEROSPACE COMPOSITE STRUCTURES

BI-DIRECTIONAL LOADING

LOAD-DISPLACEMENT RESPONSE

NONDESTRUCTIVE METHODS

PULSED THERMOGRAPHY

STRUCTURAL BEHAVIORS

Structural response

finite element method

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IIT Madras

Composite Structures

Carbon fiber-reinforced polymer structures are being increasingly used in aerospace applications. In this work, analytical, numerical, and experimental investigations are carried out to understand the structural response of debonded carbon fiber-reinforced polymer splice joint subjected to compression load. It is found that debonds are of major importance for the behavior of carbon fiber-reinforced polymer splice-joint structures. A series of carbon fiber-reinforced polymer splice-joint specimens are subjected to compressive loading by introducing an artificial debond at one of the interfaces in the splice joint and compared with specimens without debond. Although the compressive behavior is similar to that of nominal splice joint, the stiffness is considerably decreased in the presence of debond, and also the load-carrying capacity is reduced by 17% approximately. The experimental results are compared with the analytical predictions and numerical simulations using (a) the Rayleigh-Ritz method and (b) the finite element method, respectively, and are in good correlation. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Journal of Composite Materials

Performance studies on compressively loaded debonded composite splice joint

In this paper, experimental and numerical buckling studies of adhesively bonded carbon/epoxy laminates with closed debonds are investigated. To know the effect of debonds on the load bearing capability of bonded composite laminates, two sets of studies are attempted. First, the carbon fibre reinforced (CFRP) laminates are fabricated and adhesively bonded together without any artificial debonds, secondly the closed artificial debonds of desired sizes are introduced. Studies are carried out to analyze the effect of these debonds on load bearing capacity. For the experimental studies, quasi-isotropic CFRP specimens are realized with and without artificial debonds and the buckling loads are obtained from the experiment with clamped and free boundary conditions at the loading and the non-loading edges respectively. The specimens are found to exhibit a plate-column mode of buckling. Commercially available finite element package, MSC/NASTRAN has been used for numerical analysis. The experimental and numerical loads are compared and it reveals that close correlation exits between them. From the numerical analysis, it is observed that buckling load decreases when the debond size increases. © 2012 Elsevier Ltd.

Experimental and numerical studies on adhesively bonded CFRP laminates with closed debonds

The principal aim of this paper is to present a comprehensive literature survey on the defects, like debonds/delamination in composite joints/structures, focusing on the effect of defects, its growth initiation and prediction methods in fibre reinforced plastics. The effects of delaminations, its size, shape and position have been extensively studied over the past few decades. Very little attention has been paid in the area of adhesively bonded joints with closed debonds. The phenomena associated with debond in adhesively bonded composite joints require additional studies in order to allow a better understanding of the behaviour of this category when subjected to uni-axial compression. Recently virtual crack closure technique (VCCT) and cohesive zone modelling (CZM) are used as promising tools for the prediction of defects onset and its growth initiation. In this paper a comprehensive review on the prediction methods and experimental techniques are carried out and presented for the application in this field of study. © 2013 Elsevier Ltd.

Defects in composite structures: Its effects and prediction methods - A comprehensive review

The geometric nonlinear responses of laminated composite cylindrical panels subjected to (i) axial compression and (ii) central concentrated load are investigated in this work. The parameters considered are: number of layers, symmetric/antisymmetric laminate constructions, cross-ply/angle-ply fibre orientation, boundary conditions and central angle of panel. An eight-node degenerated layered shell element with an efficient explicit through-thickness integration scheme is employed. It has been observed that the cylindrical panels under axial compression exhibit stable post-buckling paths and the number of layers in the laminate for a given total thickness has considerable influence on the load-deflection behaviour. The strength of shallow panels with longitudinal edges hinged, curved edges free and subjected to a central concentrated load is controlled by the limit point load, whereas for deep panels with other parameters remaining the same, the strength is controlled by the bifurcation load. The boundary conditions have significant influence on the load-carrying capacity. The panels with longitudinal edges hinged and curved edges free should be avoided in construction, as they undergo either limit point or bifurcation failure at very low load levels compared with other edge conditions. © 2001 Elsevier Science Ltd.

Thin-Walled Structures

Nonlinear response of laminated cylindrical panels

An experimental criterion to detect onset of delamination in real time

Structural behavior of composite cylindrical splice joint panels under axial compression: Experiments and numerical studies

Journal	Data powered by TypesetComposite Structures
Publisher	Data powered by TypesetElsevier Ltd
ISSN	02638223
Open Access	No