Book reviewsComposite materials: fatigue and fracture: Edited by: H.T. Hahn ASTM STP 907, 1986 (£64.00)

The damage tolerance of Carbon Fibre Reinforced Polymer (CFRP) to Barely Visible Impact Damage (BVID) is a critical design limiter for composite structures. This study investigated the key driving mechanisms and damage evolution of the compressive failure of laminated composites containing BVID using compression after impact and indentation (CAI) tests. Experiments were carried out on two similar quasi-isotropic laminates: [45 2 /90 2 /0 2 /−45 2 ] 2S and [45/90/0/−45] 4S . Matrix cracking and delaminations were introduced by either low-velocity impact or quasi-static indentation tests prior to the CAI tests. The full-field displacement during CAI as well as the moment of rupture was captured by 3D Digital Image Correlation (DIC). The effect of ply-blocking and influence of factors, such as impact energy, delamination area and surface indentation, on compressive failure was studied. Previously validated high-fidelity finite element (FE) numerical models for the indentation and impact events were then used to investigate the damage evolution during CAI failure.

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Failure mechanisms and damage evolution of laminated composites under compression after impact (CAI): Experimental and numerical study

https://hal.archives-ouvertes.fr/hal-02126019/document

On the use of in-situ piezoelectric sensors for the manufacturing and structural health monitoring of polymer-matrix composites: A literature review

https://cyberleninka.org/article/n/510228.pdf

Full field measurements and identification in Solid Mechanics Depth-resolved Phase Imaging

The influence of low velocity repeated impacts on residual compressive properties of honeycomb sandwich structures

Identification of subsurface delaminations in composite laminates

This paper investigates the effects of precondition characteristics on the residual compressive strength (RCS) of 16-ply carbon/epoxy panels through the establishment of their compressive and buckling response characteristics. The preconditions of varying sizes include impact damage and embedded artificial delaminations of both circular and elliptical shapes. A sequence of prebuckling, local and global buckling, and postbuckling is found in both the longitudinal and transverse directions. The possibility of delamination propagation is examined using the response characteristics on the basis of the sequences. A damage threshold is found at the 25% panel width or 455mm 2damage area. Both the global buckling loads and the RCSs suffer substantial degradation but in a different manner, depending on the threshold. For small damages, the global buckling loads are unaffected but the RCSs suffer substantial degradation, though there is little evidence for the delamination propagation. For large damages, while the ...

Investigation for the Reduction of In-plane Compressive Strength in Preconditioned Thin Composite Panels:

This paper investigates the effects of damage characteristics and local curvature change on the residual compressive strength (RCS) of flat 4-mm thick carbon/epoxy panels through the examination of...

Investigation on the Reduction of In-Plane Compressive Strength in Thick Preconditioned Composite Panels

A real-time system for analysing data from speckle interferometers, and speckle shearing interferometers, has been applied to the problem of detecting and sizing sub-surface delamination cracks in carbon fiber composite panels subjected to vacuum loading. Interferograms are continuously recorded by a CCD camera at a rate of 60 frames s -1 with temporal phase shifting carried out at the same rate. Wrapped phase maps are calculated and displayed at 15 frames s -1 . These are unwrapped using a temporal phase unwrapping algorithm to provide a real-time display of the relevant displacement component. The damage identification procedure is formulated as an input output inverse problem through which system parameters are identified. The input of the inverse problem, the geometric moments (GM), is calculated from the surface displacement fields. The objective function of the optimization algorithm is defined as the squared difference between the GM obtained from the sample under test and that from a finite element (FE) model with a trial debonding. The optimum crack parameters are found by minimizing the objective function through the use of a novel implementation of real-coded genetic algorithms (ARGAs). The performance of the measurement procedure and analysis algorithms is evaluated using a set of carbon-fiber epoxy composite samples with systematically-varying and well-characterized defect geometries.

Detection and sizing of delamination cracks in composite panels using speckle interferometry and genetic algorithms

El presente articulo pretende ilustrar sobre las actuales ventajas del uso del dirigible en actividades militares, con especial enfasis en la vigilancia, para su uso potencial en Colombia. Esta alternativa de aeronave debe ser tenida en cuenta para una toma de decisiones acertada en la actual situacion de conflicto que vive el pais.

https://ojsrevistaing.uniandes.edu.co/ojs/index.php/revista/article/download/526/707

L. A. Rivera

Papers

Identification of subsurface delaminations in composite laminates

Investigation for the Reduction of In-plane Compressive Strength in Preconditioned Thin Composite Panels:

Investigation on the Reduction of In-Plane Compressive Strength in Thick Preconditioned Composite Panels

Detection and sizing of delamination cracks in composite panels using speckle interferometry and genetic algorithms

Dirigibles para vigilancia