Considerable efforts have been made in recent years to develop quantitative nondestructive evaluation (NDE) techniques for composite materials, which are being used increasingly in primary structures. The leaky Lamb wave phenomenon has shown considerable potential as an NDE method [1]. Most results reported in this area to date have been concerned with unidirectional laminates [2-4]. This is at...

Analytical solutions are sought for optimal temperature distributions to control the interlaminar stresses near the free edges of composite laminates subjected to uniaxial loading. Optimal through-thickness temperature gradients are obtained by minimizing appropriate performance indices that are functions of the far-field properties, with respect to the through-thickness temperature differences...

Composite materials are being widely used in applications including marine industry where specific properties and corrosion resistance are required. Many applications have been mentioned for pipes systems on ships, offshore platforms and also for coastal engineering plant such as power stations and desalination installations. However, it was recognized that the optimum use of composite material...

This paper presents a method for detecting multiple delaminations in composite laminates using non-contact phased arrays. The phased arrays are implemented with a non-contact scanning laser Doppler vibrometer (SLDV). The array imaging algorithm is performed in the frequency domain where both the guided wave dispersion effect and direction dependent wave properties are considered. By using the n...

This paper investigates the hygrothermal effects on the failure mechanisms in bending of carbon fibre reinforced polymer (CFRP) composites. Accelerated diffusion testing was carried out by immersion at 50°C constant temperature and 70 bar hydrostatic pressure to study the effects of fresh or sea water diffusion into pre-preg CFRP laminates. Consequently the composite laminates were tested in be...

Ionic electromechanically active polymers (IEAP) are laminar composites that can be considered attractive candidates for soft actuators. Their outstanding properties such as low operating voltage, easy miniaturization, and noiseless operation are, however, marred by issues related to the repeatability in the production and operation of these materials. Implementing closed-loop control for IEAP ...

Thermo-oxidative degradation of graphite/epoxy composite laminates due to exposure to elevated temperatures was characterized using weight loss and short beam strength (SBS) reduction data. Test specimens obtained from 24-ply, unidirectional AS4/3501-6 graphite/epoxy laminates were subjected to 100, 150, 175, and 200°C for 5000 hours (208 days) in air. Predictive differential models for the wei...

Despite the benefits of composite structures, it is only recently that the main load bearing structures in large aircraft such as the Boeing 787 and Airbus A350 have started to be manufactured using carbon fibre composites. Even then, the unique directionality properties of composite laminates have yet to be exploited to improve the aircraft performance. In this study an aluminium and composite...

We introduce asymptotic expansions for recovering the local field behavior inside multiscale composite architectures in the presence of residual stress. The theory applies to zones containing abrupt changes in the composite microgeometry. This includes the interfaces between plies inside fiber reinforced laminates. The asymptotic expansions are used to develop a fast numerical algorithm to extr...

Theoretical approaches based on bridged-crack models and plate/beam theory have proved to be effective in the modeling of Mode I and Mode II delaminations in composite laminates reinforced through the thickness. This paper deals with some aspects of the modeling of Mixed Mode delaminations. Two typical mixed mode problems are considered: the curved beam in bending (C specimen) and the Mixed-Mod...