Abstract
The science of thermal and chemical treatment of glass is well documented. The Laminated Glass (LG) is usually not treated as either treated glass is used during production or lower melting temperature of interlayer does not allow the treatment. The present work reports the novel methods of thermo-chemical treatment of LG having annealed soda lime glass plies. Five thermo-chemical treatments were performed on LG using different salts (Potassium Nitrate Carbohydrazide, Lithium Nitride), via clay coating (saturated with salts), using fused silica wafer coated with a thin graphene layer and utilizing the microwave heating. The bending strength is measured before and after thermo-chemical treatment using Q-set coupled bending tester (following the ASTM D790-03). The linear elastic model is utilized for obtaining normal stress and deformation at fracture load using ANSYS 14.5. The bending strength of thermo-chemical treated LG sample was found significantly higher than untreated LG in the most cases. The fracture pattern of the treated LG was also modified compared to the untreated LG as impurities and defects were reduced during treatment. The mechanics of increased bending strength and modified fracture is also discussed with reference to the effects of thermo-chemical treatment of LG, however, the need of a specialized numerical method that can effectively model the implications of treatment on LG and multiple fractures experienced by the LG during testing are suggested as future work.
Highlights
The higher strength and designed fracture pattern will enhance capabilities of Laminated Glass (LG) as protective glass in automotive and structural applications
The reason of variation is that the multipurpose numerical algorithm used in the present work could not follow the effect of treatment on the LG surface and a highly devoted specialized numerical algorithm is required for each treatment method to capture the actual behavior of LG after treatment from a particular method
The method 2 and the method 5 have shown a good response as a considerable increment in bending strength of LG samples is noticed
Summary
The higher strength and designed fracture pattern will enhance capabilities of LG as protective glass in automotive and structural applications. The thermal treatment includes heating the glass above its transition temperature (564 to 620°C) followed by rapid cooling by forced air drafts. The new ways of thermal treatment are attempted and reported (U.S Patent Number 5882370; 5743931; 5858047; 5022908; 5352263; 5079931; 5078774; 5059233; 5066320; 5057138) using tunnel type furnaces. Most of them have reported an incremental heating inside tunnel while glass is moving on the conveyor or similar arrangements. Such an arrangement suffers from a consequence that the temperature of the upper side and lower side of the glass has different temperature either due to rollers, support mechanism or otherwise (US Patent Number 6408649). The glass was heated after 450 to 900°C (U.S Patent Number 5232482) or 1000°C (U.S Patent Number 5306324) using powerful electric
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