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We have seen rapid expansion in the last decade of laminated glass design using modern analytical and computational methods. Essential to the proper simulation of laminated glass behavior is the development of accurate constitutive models for the polymer interlayer. Such models should reflect polymer behavior as a function of temperature and load duration so calculations may be made that reflect the design load case of interest. In this contribution we present several approaches to the determination of interlayer shear relaxation modulus behavior. Results from test methods based on dynamic mechanical analysis (shear, parallel plate geometry) are compared and contrasted. We focus on several key issues: 1) proper sample conditioning and preparation, 2) minimization of sample deformation during testing, 3) methods for TTS analysis and accurate extraction of the shear relaxation modulus, G(t), 4) validation of results using beam bending experiments. We show that self-consistent results for a specific class of interlayer may be obtained from different test geometries provided these issues are carefully managed.
Many computational tools and approaches are now available to model the deformation of laminated glass [1-7]. Indeed the development of such tools has played a key role in the expanded
In order to cover a wide range of various interlayer product stiffness, three commercial PVB interlayers, Trosifol® SC Monolayer, Trosifol® UltraClear and Trosifol® Extra Stiff, were investigated in this study
Comparison of Different Methods and Laboratories
Figure 1 gives an example of measurement comparisons for Trosifol® Extra Stiff from two different DMA geometries, shear and parallel plate, and two different laboratories
We have shown that reliable, self-consistent shear relaxation modulus, G(t), properties of polymers for laminated glass may be measured providing several important guidelines are followed. The results have also been
The authors thank Dr. Michael Kraus (Bundeswehr University Munich) for performing the 4-point bend tests and for fruitful discussions.
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