Blast loading of fibre reinforced polymer composite structures
Author(s)
Arora, Hari
Type
Thesis
Abstract
The resistance of glass and carbon fibre reinforced polymer (GFRP and CFRP)
sandwich panels and laminate tubes to blast in air and underwater environments
have been studied. Explosive charges of 0.64-100 kg TNT equivalent
were used during these studies. Procedures for monitoring the structural response
of such materials during blast events have been devised. High-speed
photography was employed during the air-blast loading of GFRP and CFRP
sandwich panels, in conjunction with digital image correlation (DIC), to monitor
the deformation of these structures under shock loading. Failure mechanisms
have been revealed using DIC and confirmed in post-test sectioning.
Strain gauges were used to monitor the structural response of similar sandwich
materials and GFRP tubular laminates during underwater shocks. The
effect of the supporting/backing medium (air or water) of the target facing
the shock has been identified during these studies. Mechanisms of failure have
been established such as core crushing, skin/core cracking, delamination and
fibre breakage. Strain gauge data supported the mechanisms for such damage.
A transition in behaviour was observed in the sandwich panels when subject
to an underwater blast as opposed to an air-blast load. Damage mechanisms
notably shifted from distributed core shear failure originating from regions of
high shear in air blast to global core crushing in underwater blast.
These studies were part of a research programme sponsored by the Office of
Naval Research (ONR) investigating blast loading of composite naval structures.
The full-scale experimental results presented in this thesis will aid and
assist in the development of analytical and computational models. Furthermore,
this work highlights the importance of support and boundary conditions
with regards to blast resistant design. These outcomes were analysed further
in finite element simulations of both air and underwater blast conditions,
where boundary stiffness and support conditions were, as expected, shown to
strongly influence structural response and deformation of the target.
sandwich panels and laminate tubes to blast in air and underwater environments
have been studied. Explosive charges of 0.64-100 kg TNT equivalent
were used during these studies. Procedures for monitoring the structural response
of such materials during blast events have been devised. High-speed
photography was employed during the air-blast loading of GFRP and CFRP
sandwich panels, in conjunction with digital image correlation (DIC), to monitor
the deformation of these structures under shock loading. Failure mechanisms
have been revealed using DIC and confirmed in post-test sectioning.
Strain gauges were used to monitor the structural response of similar sandwich
materials and GFRP tubular laminates during underwater shocks. The
effect of the supporting/backing medium (air or water) of the target facing
the shock has been identified during these studies. Mechanisms of failure have
been established such as core crushing, skin/core cracking, delamination and
fibre breakage. Strain gauge data supported the mechanisms for such damage.
A transition in behaviour was observed in the sandwich panels when subject
to an underwater blast as opposed to an air-blast load. Damage mechanisms
notably shifted from distributed core shear failure originating from regions of
high shear in air blast to global core crushing in underwater blast.
These studies were part of a research programme sponsored by the Office of
Naval Research (ONR) investigating blast loading of composite naval structures.
The full-scale experimental results presented in this thesis will aid and
assist in the development of analytical and computational models. Furthermore,
this work highlights the importance of support and boundary conditions
with regards to blast resistant design. These outcomes were analysed further
in finite element simulations of both air and underwater blast conditions,
where boundary stiffness and support conditions were, as expected, shown to
strongly influence structural response and deformation of the target.
Date Issued
2012-02
Date Awarded
2012-04
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Dear, John
Sponsor
United States. Office of Naval Research
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)