Temperature effects on laminated glass at high rate

Abstract

The load bearing capacity of a laminated glass pane changes with temperature. In blast protection, laminated glass panes with a Polyvinyl Butyral (PVB) interlayer are usually employed. The post-crack response of the laminated pane is determined by the interlayer material response and its bond to the glass plies. An experimental study has been performed to determine the effects of temperature on the post cracked response of laminated glass at a test rate of 1 m/s for PVB thicknesses of 0.76 mm, 1.52 mm and 2.28 mm. Tensile tests were carried out on single cracked and randomly cracked samples in a temperature range of 0 °C–60 °C. Photoelasticity observation and high speed video recording were used to capture the delamination in the single cracked tests. Competing mechanisms of PVB compliance and the adhesion between the glass and PVB, were revealed. The adhesion showed an increase at lower temperatures, but the compliance of the PVB interlayer was reduced. Based on the interlayer thickness range tested, the post-crack response of laminated glass is shown to be thickness dependent

High strain-rate effects from blast loads on laminated glass: An experimental investigation of the post-fracture bending moment capacity based on time–temperature mapping of interlayer yield stress

“…Nevertheless, this would result in a conservative estimation of the moment capacities at high strain-rates. Finally, the low temperature results in a stiffer adhesion bond that inhibits the delamination of the glass fragments and causes brittle failure of the PVB, as reported by Samieian et al [22] following high strain-rate tensile tests on prefractured specimens at various temperatures. This, however, does not affect the experimental work presented here, as the scope is limited to validating the post-fracture bending moment capacities, and does not include the response beyond the formation of a plastic hinge.…”

“…To ensure controlled and repeatable fracture patterns, the specimens were pre-fractured before testing, by first scoring both glass faces with a glass cutter and then impacting them at the location of the score, from both sides, to produce full-thickness cracks in each glass layer. Similar methods of pre-fracturing have been described by Nhamoinesu & Overend [41], Hooper [5] and Samieian et al [22]. Although a random pattern of irregular fragments occurs under blast loading, the pattern considered here is idealised as a series of cracks at a uniform distance of 20 mm crack spacing to allow direct comparison between tests and elicit the fundamental behaviour.…”

“…Due to the viscoelastic nature of PVB, which is time dependent, these typically involve high-speed tensile tests on PVB alone to investigate experimentally the effects of the high strain-rates that result from short-duration blast loads [4,[14][15][16][17][18][19][20][21]. Hooper [5] and Samieian et al [22] performed similar tests but on pre-fractured laminated glass specimens. These experiments highlighted the importance of the delamination of glass fragments that allow a ductile response to occur, as opposed to the brittle failure previously discussed for panels with high adhesion.…”

On the bonding between glass and PVB in laminated glass

“…Several authors have previously carried out adhesion tests using this method [3,4,5,6,7,8]. Some researchers, however, used this test method for assessing the post-crack response of laminated glass subject to blast loading [9,10]. In this test, a straight crack perpendicular to the loading direction is created coincidently on both sides of the glass specimen, before testing in tension.…”

“…These two parameters will affect the material properties of the PVB whilst stretching, and also affect the bond between the PVB and the Glass [11]. As seen in the literature, researchers have studied the rate and temperature response of the polymer, and the general cracked glass behaviour extensively [9,10]. However, issues such as temperature dependency and rate dependency of the bond have been omitted.…”