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

Angelides S. C.; Talbot J. P.; Overend M.

摘要

To enhance the resilience of buildings, laminated glass panels are increasingly used in glazed facades. These ductile panels provide a superior blast resistance to that provided by monolithic glass panels, due to the improved residual capacity offered by the polymer interlayer following the fracture of the glass layers. The complex interaction between the attached glass fragments and the interlayer is still only partially understood. To help address this, this paper investigates experimentally the post-fracture bending moment capacity of laminated glass. Three-point bending tests are performed at low temperature on specimens pre-fractured before testing, to ensure controlled and repeatable fracture patterns. The low temperature simulates the effects of the high strain-rates that result from short-duration blast loads by taking advantage of the time-temperature dependency of the viscoelastic interlayer. In these experiments, polyvinyl butyral is considered as the interlayer, this being the most common interlayer for laminated glass used in building facades. A new time-temperature mapping equation is derived from experimental results available in the literature, to relate the temperatures and strain-rates that result in the same interlayer yield stress. The results of the low-temperature tests demonstrate an enhancement of the ultimate load capacity of the fractured glass by two orders of magnitude, compared to that at room temperature. This suggests an improved post-fracture bending moment capacity associated with the now stiffer interlayer working in tension and the glass fragments working in compression. Due to the time-temperature dependency of the interlayer, a similar enhancement is therefore anticipated at the high strain-rates associated with typical blast loading. Finally, the assumed composite bending action is further supported by the results from additional specimens with thicker PVB and glass layers, which result in enhanced capacity consistent with the bending theory of existing analytical models. (C) 2020 Elsevier Ltd. All rights reserved.

机译：为了增强建筑物的韧性，叠层玻璃面板越来越多地用于玻璃门面。由于在玻璃层的断裂之后，通过由聚合物中间层提供的改善的残余能力，这些延展板为单片玻璃板提供的整体玻璃板提供了卓越的爆破抗性。附着的玻璃片段和中间层之间的复杂相互作用仍然仅部分地理解。为了帮助解决这一点，本文研究了实验性夹层玻璃后断裂弯矩能力。在测试前在预裂缝预裂缝的低温下进行三点弯曲试验，以确保受控和可重复的裂缝图案。低温通过利用粘弹性中间层的时间温度依赖性来模拟短脉冲率产生的高应变率的影响。在这些实验中，聚乙烯醇缩丁醛被认为是中间层，这是用于建筑物外墙的层压玻璃中最常见的中间层。新的时温映射方程源自文献中可获得的实验结果，以涉及导致相同的层间屈服应力的温度和应变率。与室温相比，低温试验结果表明，通过两个数量级的折损玻璃的最终负载能力提高了两种数量级。这表明与在紧张的张力中工作的现在更硬的中间层和在压缩中工作的玻璃碎片相关联的后骨折后弯矩容量。由于中间层的时间温度依赖性，因此预期与典型喷射载荷相关的高应变率的类似增强。最后，通过具有较厚的PVB和玻璃层的额外标本的结果进一步支持假定的复合弯曲动作，这导致与现有分析模型的弯曲理论一致的增强容量。（c）2020 elestvier有限公司保留所有权利。

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

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