Advances in window glass design

The finite difference method and the finite element method are the most commonly used mathematical tools to numerically characterize the mechanical behavior of window glass. The finite element method is increasingly popular due to its flexibility in analyzing bodies with complex geometries and the option to solve mechanics problems without use of the governing partial differential equations. These advantages allow the analyses of various glass applications, such as point- supported glass and insulating glass units, using the same finite element routine. A two-dimensional, four-node, nonlinear quadrilateral finite element formu- lation is advanced incorporating the Von Karman assumptions into the Reissner- Mindlin plate theory to analyze monolithic and laminated glass lites undergoing large deflections due to applied lateral loads. The assumed transverse shear strain fields method is employed to mitigate shear locking, and the shear stiffness terms are fully integrated. The finite element formulation is benchmarked against ex- perimental test results for laminated glass subjected to an applied uniform load. The numerical and test results are found to be in good agreement. The finite element formulation and a modified glass failure prediction model are applied to determine the load resistance of point-supported glass. Numerical results show that the load resistance of point-supported glass vary as a function of glass lite geometry and hole location. Furthermore, the tensile stress concen- trations at the exterior surface of the lite are the primary driver controlling the load resistance of point-supported glass. The finite element formulation is further applied to analyze insulating glass units simply supported along two parallel sides and three sides subjected to applied uniform lateral loads. The spacer separating the glass lites apart is assumed to behave as an Euler beam along the unsupported edges. Numerical results show that the load sharing and mechanical behavior of partially supported insulating glass units vary as a function of spacer flexural rigidity and/or aspect ratio. As the spacer flexural rigidity is increased, the behavior of partially supported insulating glass units tends towards that of units simply supported along four sides.