In the last two decades, a significant number of innovative sensing systems based on optical fiber sensors have been exploited in the engineering community due to their inherent distinctive advantages such as small size, light weight, immunity to electromagnetic interference (EMI) and corrosion, and embedding capability. A lot of optical fiber sensor-based monitoring systems have been developed for continuous measurement and real-time assessment of diversified engineering structures such as bridges, buildings, tunnels, pipelines, wind turbines, railway infrastructure, and geotechnical structures. The purpose of this review article is devoted to presenting a summary of the basic principles of various optical fiber sensors, innovation in sensing and computational methodologies, development of novel optical fiber sensors, and the practical application status of the optical fiber sensing technology in structural health monitoring (SHM) of civil infrastructure.

https://downloads.hindawi.com/journals/tswj/2014/652329.pdf

Structural health monitoring of civil infrastructure using optical fiber sensing technology: a comprehensive review.

A model to predict low-velocity impact response and damage in sandwich composites

This contribution is a review of past and current research progress on dynamic response of composites sandwich structures subjected to low-velocity impact. To obtain a comprehensive overview of the current state-of-the-art published works, impact responses on sandwich structures are broadly classified into two main groups, high-velocity and low-velocity impacts, with the focus on low-velocity impact. A summary of some of the commonly used theoretical solutions for low-velocity impact is provided and described in some details. The response of low-velocity impact has been determined based on mass ratio, which is defined as the ratio of the impact mass to effective mass of the structural component. As a result, the response under low-velocity impact was further subdivided into three possible categories, namely, large, small, and medium mass impacts. For each category of impact, currently available suitable solutions are discussed in details. To classify the response of low-velocity impact and also to explore...

A review of low-velocity impact on sandwich structures

Interfacial bonding, essential to carbon-fiber and aluminum-honeycomb sandwich composites and their structural performance, was investigated under bending and uniaxial compression in this study. The feasibility and effectiveness of short Kevlar-fiber interfacial toughening at the interface between the carbon-fiber face sheets and aluminum-honeycomb core were examined. It was observed that the adhesive joint, in-situ formed from resin and short Kevlar fibers at the interface effectively became a composite. Protruding free fiber ends of the short Kevlar fibers, connecting or bridging the face sheets and core, had effectively increased the adhesion contact areas at both sides of the adhesive joint, leading to strong fiber-bridging in case of interfacial cracking. The peak load and energy absorption of the sandwich composites, with and without the short Kevlar-fiber interfacial toughening, were compared with predictions from analytical models. Toughening and strengthening mechanisms of the reinforced adhesive fillets were explained together with detailed fractography observations.

Carbon-fiber and aluminum-honeycomb sandwich composites with and without Kevlar-fiber interfacial toughening

Cellular metals with stochastic, 2D or 3D periodic microstructures can sustain large plastic deformation at almost constant stress. Due to such excellent energy absorption capability, cellular metals are very suited to be used as the core of sandwich structures, which have been applied widely to the areas of aerospace and aeronautical design, the automotive manufacturing, and shipbuilding, as well as the defense and nuclear industries. Although there is a great deal of research currently available related to the behaviour of sandwich structures with metallic cellular core under various loading conditions, they are widely scattered in the literature. This review paper brings together the latest developments in this important research area. Three types of cellular metals, namely metal foams, honeycombs and prismatic materials and truss and textile based lattice materials are considered. The responses of sandwich structure with such cores subjected to different loads, i.e. quasi-static/low velocity compression and indentation, ballistic impact, high speed compression and blast loading, are reviewed. The emphasis has been placed on their plastic deformation, failure and energy absorption behaviours.

https://researchbank.swinburne.edu.au/file/493d90e4-55f2-49e9-b22c-1fd70b80dee8/1/PDF (Published version).pdf

Plastic Deformation, Failure and Energy Absorption of Sandwich Structures with Metallic Cellular Cores

Damage characteristics of composite-skinned honeycomb sandwich panels in bending are investigated with both hemispherical (HS) and flat-ended (FE) indenters. The thickness of the cross-ply skins va...

Damage Characteristics of Composite Honeycomb Sandwich Panels in Bending under Quasi-static Loading

This paper reports on research work which is a comprehensive study involving the design of an extrinsic Fabry–Perot interferometric strain sensor (EFPI-SS), the manufacture of smart carbon/epoxy beams preconditioned with artificial delamination, and the testing of these beams in three-point bending. A loading applied to the beams was quasi-static in nature and this was selected in order to facilitate the accurate and reliable control of the beam deformations. The EFPI-SSs were validated for their sensing capacity and survivability via surface mounting and interior embedment. Artificial delaminations of two different sizes were embedded within the host beams to simulate damage. Their effect on the bending stiffness induced by quasi-static loading was examined using the embedded EFPI-SSs along with surface-mounted conventional strain gauges (SGs) on a comparative basis. A linear response was obtained from the EFPI-SSs up to a strain level of 0.5%, and this was in good agreement with interpolated strains as well as those from analytical prediction. It was shown that the embedded EFPI-SSs were able to differentiate the effect of the tensile delaminations on the bending stiffness when the level of strain was substantial. It was noted that the interior strain data from the EFPI-SSs in conjunction with the surface SG data were very useful for extrapolating the strain difference on both sides of the delaminations, so that the possibility of delamination propagation could be deduced.

http://iopscience.iop.org/article/10.1088/0964-1726/13/6/003/pdf

J. Loughlan

Papers

Damage Characteristics of Composite Honeycomb Sandwich Panels in Bending under Quasi-static Loading

Damage evaluation of smart composite beams using embedded extrinsic Fabry–Perot interferometric strain sensors: bending stiffness assessment