Experimental observations of intersonic crack growth in asymmetrically loaded unidirectional composite plates

Date

2001-01-01

Author

Çöker, Demirkan

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

113
views

0
downloads

Some recent experimental observations of highly dynamic crack growth events in thick unidirectional composites are presented. The specimens used in this study were 48-ply thick unidirectional graphite-epoxy composite plates which were either symmetrically (mode I) or asymmetrically (mode II) loaded by impact in a one-point bend configuration with an edge pre-notch machined in the fibre direction. Moderate impact speeds of up to 57 m s(-1) were used. The lateral shearing interferometric technique of coherent gradient sensing in conjunction with high-speed photography was used to visualize the failure process in real time. Mode-I cracks propagated subsonically with crack speeds increasing to the neighbourhood of the Rayleigh wave speed. For asymmetric mode-II types of loading the results revealed highly unstable and intersonic shear-dominated crack growth along the fibres. These cracks propagated with unprecedented speeds reaching 7400 m s(-1): a speed which is more than three times the shear wave speed of the composite and almost equal to the dilatational wave speed of the composite along the fibres. For intersonic crack growth, the interferograms featured a shock wave structure typical of disturbances travelling with speeds higher than one of the characteristic wave speeds in the solid. Evidence of large-scale frictional contact is also presented.

Subject Keywords

Field, Fracture, Mechanics, Propagation, Bimaterial

URI

https://hdl.handle.net/11511/36565

Journal

Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties

DOI

https://doi.org/10.1080/01418610108212160

Collections

Department of Aerospace Engineering, Article

Suggestions

OpenMETU
Core

Numerical modelling of wave-structure interaction problems through cfd methods Güler, Hasan Gökhan; Yalçıner, Ahmet Cevdet; Department of Civil Engineering (2020) The major focus of this study is the computational fluid dynamics (CFD) modelling of wave-structure interaction problems. In the first part of this study, the performance of Haydarpaşa Breakwater under tsunami attack is assessed both experimentally and numerically. It is concluded that the major failure mechanism of this breakwater is the sliding of the crown-wall, and the stability of the stones located at the harbour side is also significant. Design recommendations are given based on the stability of the ...
Experimental investigation of turbulent flow and wind comfort characteristics of fractal wind fences Çoşkun, Şemsi; Kurç, Özgür; Department of Civil Engineering (2017) The characteristics of turbulent flow behind the fractal fences are rather new research area. Previous studies on fractal fences showed that there are clear differences in the flow characteristics as compared with the conventional fences. This study presents the results and comparisons of an experimental study that investigates the turbulent flow and wind comfort characteristics of fractal wind fences. Four different wind fences, three of which have fractal geometries, with the same height, width, and poros...
Experimental evaluation of geomembrane/geotextile interface as base isolating system Kalpakci, V.; Bonab, A. T.; Özkan, M. Yener; Gülerce, Zeynep (Thomas Telford Ltd., 2018-02-01) The objective of this study is to evaluate the effect of the geomembrane/geotextile interface on the seismic response of small-to-moderate height structures. Three building models with first-mode natural frequencies changing between 2-4 Hz (representing two, three and four storey structures) were tested with and without the addition of geomembrane/geotextile interface using the shaking table test setup by employing harmonic and modified/ scaled ground motions. Experimental results showed that the geomembran...
Assessment and modelling of particle clustering in cast aluminum matrix composites Çetin, Arda; Kalkanlı, Ali; Department of Metallurgical and Materials Engineering (2008) The damage and deformation behaviour of particle reinforced aluminum matrix composites can be highly sensitive to local variations in spatial distribution of reinforcement particles, which markedly depend on melt processing and solidification stages during production. The present study is aimed at understanding the mechanisms responsible for clustering of SiC particles in an Al-Si-Mg (A356) alloy composite during solidification process and establishing a model to predict the risk of cluster formation as a f...
Modeling selected X-ray observations of nonmagnetic cataclysmic variables using XMM-Newton and Swift observatories Nabizadeh, Armin; Balman, Şölen; Department of Physics (2017) Despite of recent developments in observational techniques, the diversity of the X-ray observations of nonmagnetic Cataclysmic Variables (CVs) are still not entirely understood. In this work, we plan to review the X-ray spectral characteristics of such systems during their quiescence state which in general explained by the multi-temperature plasma emission models and also, the CV spectra that show dominantly hard X-ray emission with few sources that reveal soft X-ray/EUV blackbody emission. For this purpose...

Citation Formats

D. Çöker, “Experimental observations of intersonic crack growth in asymmetrically loaded unidirectional composite plates,” Philosophical Magazine A: Physics of Condensed Matter, Structure, Defects and Mechanical Properties, pp. 571–595, 2001, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36565.