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The use of optical techniques to assess the damage tolerance of composite materials

The use of optical techniques to assess the damage tolerance of composite materials
The use of optical techniques to assess the damage tolerance of composite materials
Experimental methodologies based on full-field optical techniques for the study of damage in fibre reinforced polymer (FRP) materials, during intermediate strain rate loading and subsequent fatigue loading are established. The methodologies are based on thesynchronous use of digital image correlation (DIC) and infra-red (IR) thermography, allowing the collection of full-field kinematic and thermal surface data maps to provide a deeper insight into the damage mechanisms and a new capability for identifying damage in FRP materials and structures.

The study of damage initiation in FRP materials during intermediate strain rate loading requires the application of high speed cameras and the development of a novel loading rig capable of imparting a damaging load that does not fail the material. The rig design is fully validated. The application of DIC on images obtained using high speed cameras is evaluated. New approaches to identify the effect of sensor fill-factor on the accuracy of high spatial resolution DIC strain measurements are devised. Data captured from crossply carbon-epoxy and glass-epoxy specimens demonstrate the capability of combining DIC and IR-thermography in identifying damage during an intermediate strain rate loading event.

A novel semi-automated methodology for the accurate triggering of high resolution white-light and IR images during a fatigue test is described, which allows the synchronous capture of data that enables DIC and thermoelastic stress analysis (TSA) to be applied without the pausing of a cyclic load. The combined methodology is applied to crossply glass-epoxy and carbon-epoxy specimens, identifying various damage types including; transverse cracking, delaminations and longitudinal splitting, verified through the use of X-ray computed tomography (CT).

Finally, future improvements are recommended with an aim of future users applying the optical methodologies to a greater range of loading scenarios and to the study of a greater range of material types and laminate configurations, so informing on the future design of damage tolerant FRP structures.
Battams, Gary
20d5c1e1-f576-4a73-9d5e-189abbf82322
Battams, Gary
20d5c1e1-f576-4a73-9d5e-189abbf82322
Barton, Janice
9e35bebb-2185-4d16-a1bc-bb8f20e06632

Battams, Gary (2014) The use of optical techniques to assess the damage tolerance of composite materials. University of Southampton, Faculty of Engineering and the Environment, Doctoral Thesis, 273pp.

Record type: Thesis (Doctoral)

Abstract

Experimental methodologies based on full-field optical techniques for the study of damage in fibre reinforced polymer (FRP) materials, during intermediate strain rate loading and subsequent fatigue loading are established. The methodologies are based on thesynchronous use of digital image correlation (DIC) and infra-red (IR) thermography, allowing the collection of full-field kinematic and thermal surface data maps to provide a deeper insight into the damage mechanisms and a new capability for identifying damage in FRP materials and structures.

The study of damage initiation in FRP materials during intermediate strain rate loading requires the application of high speed cameras and the development of a novel loading rig capable of imparting a damaging load that does not fail the material. The rig design is fully validated. The application of DIC on images obtained using high speed cameras is evaluated. New approaches to identify the effect of sensor fill-factor on the accuracy of high spatial resolution DIC strain measurements are devised. Data captured from crossply carbon-epoxy and glass-epoxy specimens demonstrate the capability of combining DIC and IR-thermography in identifying damage during an intermediate strain rate loading event.

A novel semi-automated methodology for the accurate triggering of high resolution white-light and IR images during a fatigue test is described, which allows the synchronous capture of data that enables DIC and thermoelastic stress analysis (TSA) to be applied without the pausing of a cyclic load. The combined methodology is applied to crossply glass-epoxy and carbon-epoxy specimens, identifying various damage types including; transverse cracking, delaminations and longitudinal splitting, verified through the use of X-ray computed tomography (CT).

Finally, future improvements are recommended with an aim of future users applying the optical methodologies to a greater range of loading scenarios and to the study of a greater range of material types and laminate configurations, so informing on the future design of damage tolerant FRP structures.

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More information

Published date: 14 January 2014
Organisations: University of Southampton, Engineering Mats & Surface Engineerg Gp

Identifiers

Local EPrints ID: 363784
URI: http://eprints.soton.ac.uk/id/eprint/363784
PURE UUID: 7ae5bca5-d2d6-49a5-8b09-b448ae8056d1

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Date deposited: 10 Apr 2014 15:38
Last modified: 18 Jul 2017 02:35

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