Monitoring and characterization of the interfacial fracture in sandwich composites with embedded multiplexed optical sensors

Interfacial debonding is one of the most critical damage modes that threatens the structural performance of sandwich composites. In this work, integrated multiplexed fiber Bragg grating (FBG) sensors of 1 mm gauge length are used for detection and characterization of crack propagation along the face-core interface. Single cantilever beam specimens incorporating arrays of FBG sensors are subjected to monotonic and fatigue debonding tests. The experimental configurations are simulated by finite element method in order to verify the experimental procedures and analyze the strain data corresponding to the location of the embedded FBGs. It is demonstrated that the embedded FBGs can successfully reveal the strain field imposed by the interface crack into the sandwich face. The good agreement between the experimental results and concurrent numerical simulations suggests that such data can be used for monitoring of interfacial fatigue and fracture in sandwich structures. (C) 2012 Elsevier Ltd. All rights reserved.

[1]  W. Cantwell,et al.  A study of skin-core adhesion in glass fibre reinforced sandwich materials , 1996 .

[2]  George A. Kardomateas,et al.  Structural and Failure Mechanics of Sandwich Composites , 2011 .

[4]  F. Bosia,et al.  Through-the-thickness distribution of strains in laminated composite plates subjected to bending , 2004 .

[5]  Leif A. Carlsson,et al.  Analysis of the sandwich DCB specimen for debond characterization , 2008 .

[6]  K. Peters,et al.  Embedded optical fiber Bragg grating sensor in a nonuniform strain field: Measurements and simulations , 2001 .

[7]  John Botsis,et al.  Monitoring of non-homogeneous strains in composites with embedded wavelength multiplexed fiber Bragg gratings: A methodological study , 2012 .

[8]  D. Zenkert,et al.  Handbook of Sandwich Construction , 1997 .

[9]  Z. Suo,et al.  Mixed mode cracking in layered materials , 1991 .

[10]  W. Cantwell,et al.  A test technique for assessing core-skin adhesion in composite sandwich structures , 1994 .

[11]  S. Smith,et al.  Modified Mode-I Cracked Sandwich Beam (CSB) Fracture Test , 2001 .

[12]  James R. Reeder,et al.  Sizing Single Cantilever Beam Specimens for Characterizing Facesheet/Core Peel Debonding in Sandwich Structure , 2013 .

[13]  J. Botsis,et al.  Studies of mode I delamination in monotonic and fatigue loading using FBG wavelength multiplexing and numerical analysis , 2011 .

[14]  Nobuo Takeda,et al.  Detecting an Arrested Crack in a Foam-Core Sandwich Structure Using an Optical Fiber Sensor Embedded in a Crack Arrester , 2011 .

[15]  Leif A. Carlsson,et al.  The Tilted Sandwich Debond (TSD) Specimen for Face/Core Interface Fracture Characterization , 1999 .

[16]  Joël Cugnoni,et al.  Crack – fiber sensor interaction and characterization of the bridging tractions in mode I delamination , 2011 .

[17]  Nobuo Takeda,et al.  Real-time Detection of Debonding between Honeycomb Core and Facesheet using a Small-diameter FBG Sensor Embedded in Adhesive Layer , 2007 .

[18]  S. Abrate,et al.  Structural Monitoring with Fiber Optic Technology , 2001 .