Research On Dynamic Response And W-R Method For Blast Resistant Design Of Laminated Glass

With the progress of science and technology, building glass such as laminated glass is widely used in glass curtain wall structures of modern buildings. In recent years, the terrorist attacks occur frequently, the objects of the attacks are from military facilities to civil buildings and the grade of the blast load is bigger than that of conventional building design load(wind load). The glass curtain wall design specifications of JGJ 102-2003 and JGJ 113-2009 in our country are only related on the static wind load and others, not for blast resistance. Some researchers have taken the effect of blast load on the glass curtain wall into consideration, such as iso-damage figure and P- I figure, but they don’t consider the effect of negative phase of blast. Moreover, some researchers puts forward the empirical formula of safe distance, which doesn’t consider the effect of negative phase of blast, either. Ratio of width to height is fixed constant to consider the worst case, and the accuracy of theoretical calculation of the stress is quite low. At present, the calculation method of the dynamic theory of laminated glass object is limited to flat laminated glass panels with simply supported boundary. In fact, the boundary is between simply supported and fixed supported, it is necessary to do some supplementary research of fixed boundary. Due to the need of modeling or others for design, curved laminated glass panels also have some applications, but the dynamic response calculation method and blast resistance research of the laminated glass curved panels are rare. In view of facts that the existing blast resistance design method has disadvantages and the research of curved laminated glass panels is rare, this paper studies the influent factors of calculation accuracy of flat laminated glass dynamic response and the simple calculation theory for the dynamic response of the curved laminated glass panels, and establishs a design method of blast resistance(W – R method) for the laminated glass flat or curved panels with fixed supported boundary at the same time, in order to provide reliable basis for the blast resistance design and construction for glass curtain wall under blast impact load. The concrete research content is as follows:(1) With fixed boundary conditions, the theoretical calculation method of the deflection and stress for flat laminated glass panels under blast impact load is derived, combined with study of PVB elastic modulus, PVB thickness and glass thickness on the accuracy of theoretical calculation by the finite element simulation, discussing the rationality of the basic assumptions; Research on the dynamic responses differences between the curved laminated glass panels and flat laminated glass panels with the same size, the paper finds two stability factor A and B and establishes a feasible method to calculate the dynamic responses of curved laminated glass panels.(2) The rationality of the finite element model is verified by Kranzer test by finite element simulation, the paper studies the defects of the blast resistance design method(P- I figure) under blast with negative phase, and sets up an intuitive, feasible W- R design method for blast resistance. At the same time, PVB thickness, different thickness of inside and outside layer glass, multilayers, glass thickness, area, ratio of width to length, all are discussed by W- R figure. This paper fits out the W- R empirical formula for flat laminated glass panels, and studies the critical equivalent distance Z to evaluate the effects of negative phase of blast.(3) The paper also explores W- R design method for curved laminated glass panels. Through the theory forecast model of enhancement coefficient of , the W- R design method is verified feasible for curved laminated glass panels from the mechanism level, which is multiplied by the coefficient of on the basis of the same size of flat laminated glass panels. The paper studies the effects of glass thickness, area, ratio of width to length and the bending degree on the enhancement coefficient of , and fits empirical formula for enhancement coefficient of . At the same time, the qualitative analysis on influences of negative phase of blast on W- R design method for curved laminated glass panels is included.