Study On Blast-resistance Performance Of Laminated Glass Considering With Negative Phase

Architectural glass is widely used in iconic high-rise buildings with its characteristics of combining technologies with functions and arts all around the world. Although the blast resistant design methods of glass curtain wall exist on domestic and foreigndesign methods, these methods still need further perfection. According to iso-damage figures and P-I figures, along with simple calculation, they can estimate whether certain glass structures under explosion load damage or not. However, the P-I figure method of evaluating blast resistant ability of glass curtain walls has not yet considered the effect of negative phase of blast. Besides, it lacks quantitative empirical formulas to evaluate effects of negative phase of blast on the blast resistant ability.According to the research status above, based on the stress wave theory, vibration theory, elastic-plastic mechanics and so on, the paper study the problems of dynamic response of glass curtain walls under explosion load by using explicit dynamic finite element software LS-DYNA. By comparing the P-I figure with considering negative phase of blast with the P-I figure without, the paper study the relationship between the inherent frequency of laminated glass and whether negative phase of blast has effect or not by qualitative and quantitative analysis. Then the paper researches the explosion load magnitude, different size combination, PVB thickness and multilayer laminated glass structure and their effects on laminated glass dynamic responses, getting a lot of critical P-I figures under different cases. By parameters study, this paper gets the empirical formulas of critical value P0 and I0, which corresponds to the horizontal and vertical asymptote of P-I graph and can be used for evaluating the blast-resistance ability for laminated glass. Finally the paper puts forward optimized design scheme to improve the blast-resistance ability for laminated glass, in order to give some guides for the design of glass curtain walls.The paper has several conclusions: In general, the greater the laminated glass size, the lower the natural frequency, the ratio of t+/T is more likely to be small value and the greater effect of negative phase of blast. When the negative phase of blast should not be neglected, P-I figure loses general law in the vertical section and appears multi-values phenomenon, resulting in being applied to design guidance with difficulty. However, ignoring the influence of negative phase will overestimate the blast-resistance ability of laminated glass. The horizontal asymptote of P-I figure is not affected by negative phase, so it should be safe to design according to horizontal asymptote and obtains empirical formula of critical value P0 Vertical asymptote I0 are greatly influenced by negative phase, if the design is calculated by empirical formula I0 within the scope of the critical distance, it will be safe. Otherwise, it will be reasonable.