Numerical simulation of low velocity, small missile impact of laminated architectural glass

Laminated architectural glass commonly used in large high rise buildings is frequently subjected to small, low velocity missile impact during severe windstorms such as hurricanes. Windborne debris such as roof gravel can attain sufficient velocity to break windows. Broken windows can cause injury to pedestrians on the street and to building occupants as well as extensive hurricane related damage to the building contents. The disruption of normal business activity following such damage is also costly. The need for improved impact resistance in laminated architectural glass is therefore great.; The current method of improving the impact performance of laminated architectural glass is through expensive and time consuming laboratory tests. Therefore, the benefit of relatively fast and inexpensive computer simulation is obvious. Traditional finite element wave propagation codes are useful for simulating impact events; however their use is limited in an engineering structure such as laminated glass because fracture and delamination of the glass plies are difficult to model. Because fracture and delamination are important to the impact performance of laminated glass, current generation finite element wave propagation codes are unsuitable for the level of simulation required. A set of computational algorithms are developed that allow the computer simulation of small, low velocity missile impact of laminated architectural glass by traditional finite element wave propagation codes. The algorithms are successfully incorporated into an existing code. The effects of glass fracture, interlayer delamination, and various material and geometric parameters on the overall impact performance of laminated glass are presented.