Blast performance of silicone-bonded laminated glass
Author(s)
Hooper, Paul
Type
Thesis
Abstract
Blast resistant glazing systems typically use laminated glass to reduce
the risk of flying glass debris in an explosion. Laminated glass has a
bonded polymer interlayer that retains glass fragments upon fracture.
With proper design, the flexibility of the interlayer in laminated glass
can offer protection from significantly higher blast loads when compared
to an equivalent monolithic pane. This thesis investigates the
post-fracture behaviour of laminated glass under blast loading and
aims to build the knowledge required to improve design methods for
blast resistant glazing.
Full-scale open-air blast tests were performed on laminated glass
containing a polyvinyl butyral (PVB) interlayer. Test windows ranged
in size from 1.5m×1.2m to 3.5m×1.8m and were bonded to robust
frames using structural silicone sealant. Blast loads were produced using
charge masses of 15 kg to 500 kg (TNT equivalent) and distances
of 10m to 30 m. Deflection and shape measurements were obtained
using high-speed digital image correlation. Measurements of loading
at the joint were also made with strain gauges. The main failure mechanisms
observed were the cohesive failure of the bonded silicone joint
and tearing of the interlayer.
These failure mechanisms were investigated further using a highspeed
tensile test machine to reproduce blast loading conditions.
Cracked laminated glass samples were loaded in tension at varying
rates. Their response was characterised by a rate dependant plateau
force which can be used to estimate the maximum load on the glazing
joint. Delamination between the PVB and glass was found to play
a key role in the laminate response. Thinner PVB and higher strain
rates reduced the delamination area, leading to premature tearing of
the interlayer. The strength of structural silicone sealant in a blast situation
was also investigated. A novel test method was used to determine
the bond length required to retain the laminated glass window in
a blast event. A nominal strength of not greater than 1.1MPa should
be used for design of conventional single-sided silicone joints.
A finite element model of the laminated glass response to blast
loading was developed using the results of the experimental investigations.
The failure predictions of the model were compared against
a single-degree-of-freedom (SDOF) model and showed good agreement.
Differences in the deflected shape at maximum deflection were
seen between the model and those measured in blast testing.
the risk of flying glass debris in an explosion. Laminated glass has a
bonded polymer interlayer that retains glass fragments upon fracture.
With proper design, the flexibility of the interlayer in laminated glass
can offer protection from significantly higher blast loads when compared
to an equivalent monolithic pane. This thesis investigates the
post-fracture behaviour of laminated glass under blast loading and
aims to build the knowledge required to improve design methods for
blast resistant glazing.
Full-scale open-air blast tests were performed on laminated glass
containing a polyvinyl butyral (PVB) interlayer. Test windows ranged
in size from 1.5m×1.2m to 3.5m×1.8m and were bonded to robust
frames using structural silicone sealant. Blast loads were produced using
charge masses of 15 kg to 500 kg (TNT equivalent) and distances
of 10m to 30 m. Deflection and shape measurements were obtained
using high-speed digital image correlation. Measurements of loading
at the joint were also made with strain gauges. The main failure mechanisms
observed were the cohesive failure of the bonded silicone joint
and tearing of the interlayer.
These failure mechanisms were investigated further using a highspeed
tensile test machine to reproduce blast loading conditions.
Cracked laminated glass samples were loaded in tension at varying
rates. Their response was characterised by a rate dependant plateau
force which can be used to estimate the maximum load on the glazing
joint. Delamination between the PVB and glass was found to play
a key role in the laminate response. Thinner PVB and higher strain
rates reduced the delamination area, leading to premature tearing of
the interlayer. The strength of structural silicone sealant in a blast situation
was also investigated. A novel test method was used to determine
the bond length required to retain the laminated glass window in
a blast event. A nominal strength of not greater than 1.1MPa should
be used for design of conventional single-sided silicone joints.
A finite element model of the laminated glass response to blast
loading was developed using the results of the experimental investigations.
The failure predictions of the model were compared against
a single-degree-of-freedom (SDOF) model and showed good agreement.
Differences in the deflected shape at maximum deflection were
seen between the model and those measured in blast testing.
Date Issued
2011-03
Date Awarded
2011-04
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Blackman, Bamber
Dear, John
Sponsor
Arup Security Consulting and the Engineering and Physical Sciences Research Council (EPSRC)
Creator
Hooper, Paul
Publisher Department
Mechanical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)