Nonlinear finite element analysis of glass panels

Glass panels which are widely used in curtain wall systems, behave nonlinearly under high wind load when their deflections exceed about 3/4 of their thickness. The American and the Canadian design codes for curtain wall and window systems have made it mandatory to include the effect of large deflection in the design and analysis of glass panels. This paper presents a versatile finite shell element method for nonlinear analysis of glass panels subjected to high wind loads. The accuracy of the proposed method is demonstrated via comparison with the results of previous studies and experiments. The advantage of the present method is its versatility in handling complex loading and boundary conditions whilst its longer computational time has been effectively offset by the adoption of the efficient incremental-iterative minimum residual displacement method of analysis and the availability of fast personal computers. Using the examples studied in this paper, it was found that the nonlinearity in glass may violate the linear assumption in the practical loading range, resulting in unexpected glass behaviour if the linear theory is used. More interestingly, the use of higher strength glass, the tempered or the heat-strengthened glass, will not increase the load resistance of the panel when it is under in-plane loads causing instability.