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Recent explosions have prompted researchers to investigate the vulnerability of civil structures, leading to an increased demand for blast-resistant buildings. Laminated glass (LG) panels in glazed facades boost resilience, yet understanding glass fragment interaction with interlayers remains incomplete. This paper presents an integrated experimental-computational study on strain localization in LG polymeric interlayers to accurately simulate their response, addressing this gap. Uniaxial tensile tests were performed on the polymeric interlayer materials polyvinyl butyral (PVB) and SentryGlas® (SG), commonly used in the design of LG in blast-resistant glazing systems. Digital image correlation was used to characterize strain localization within the material. The experimental results were used to calibrate material model parameters to be used in the modeling of LG systems. A three-network viscoplastic (TNV) material model for SG interlayer was calibrated using PolymerFEM software. Yeoh hyperelastic material model parameters were calibrated for the quasistatic response of PVB. A finite element computational model was developed using Ansys LS-DYNA software and validated with experimental data. The study results showcase finite element modeling's ability to accurately predict both the hyperelastic response of PVB and the post-peak large strain behavior of SG interlayer materials by 8% and 3.6%, respectively.

It is known that weathering action has a significant impact on polymer interlayer materials, and previous studies have evaluated certain aspects of weathering such as temperature, humidity, and UV radiation. In this paper, the environmental effect on the mechanical properties of the virgin and cured/processed polymer interlayer materials will be studied. Three polymer interlayer materials were focused, i.e., Polyvinyl butyral (PVB), Ethylene-vinyl acetate (EVA), and Ionomer (SG), due to their industrial interest. Testing setups were designed to apply the environmental effects and perform mechanical testing on the polymeric materials. Four environmental effects were studied, including water submersion (E1), constant high temperature (E2), cyclic temperature with low relative humidity (E3), cyclic temperature, and relative humidity (E4). After the exposure of these materials to these environmental effects, the samples were prepared and mechanically tested. Uniaxial tests were performed under static and high strain rates (around 45−1). It was found that under dynamic load, the properties of EVA such as the strength, maximum strain, and the toughness were not significantly affected by the environmental effects. SG5000 properties were significantly affected. [ABSTRACT FROM AUTHOR]

In this paper, the static and dynamic constitutive behavior of aged and unaged virgin PVB were evaluated at different strain rates using static and impact drop-weight testing. The aged virgin PVB was subjected to random environmental conditions of different temperature and moisture levels. All static tests were performed at room temperature ranging between 21 and 32 °C. The results showed that the aged and unaged virgin PVB dynamic constitutive response consists of two linear parts. The first part is linearly elastic and independent of the rate of loading. However, the second linear part was found to be dependent on the strain rate. Aging significantly affected both the static and dynamic constitutive stress-strain relations. Comparing aged and unaged high-strain rate results showed that aging significantly affects the material response of the interlayer materials used in laminated glass, and subsequently, their dynamic response under blast loads. For the aged material tested in this paper, the strain rate effect was found to be less significant in the current test temperature range. [ABSTRACT FROM AUTHOR]

Laminated glass interlayer materials polyvinyl butyral (PVB) and SentryGlas ® (SG, kuraray, Houstan, TX, USA) exhibit thermal viscoelastic behavior under dynamic tensile loading. Significant temperature and strain rate effects on the behavior of these interlayer materials pose a challenge for accurately modeling the dynamic response of laminated glass. Many researchers have simplified their approaches by modeling the response of the interlayer material using a bilinear approximation or established hyperelastic models. However, temperature and strain rate effects can be captured using the three-network viscoplastic (TNV) model. Therefore, the objective of this study is to calibrate material models for the thermal viscoelastic dynamic responses of PVB and SG interlayer materials. Uniaxial tensile tests were performed at strain rates of 2, 20, and 45 s -1 and temperatures of 0, 23, and 60 °C, and material models were calibrated using the experimental data. Finite element analysis using the calibrated material models successfully predicted the dynamic responses of PVB and SG under the experimental test conditions within a 10% error margin. This suggests that the calibrated models using the TNV model represent significant improvements over existing approaches to modeling the dynamic response of laminated glass. Similar procedures can be applied to other thermoplastics, laying the groundwork for establishing a standard calibration guide.