Protective bollard design for high speed impact energy absorption
As is passenger safety of paramount importance to the manufacturer of passenger vehicles, so is the security of the nation to its government. Recent developments in the usage of heavy vehicles by militant outfits to carry out attack has become the main concern of many governments around the world, hence the existence of some kind of barrier to stop heavy vehicles from entering restricted areas was thought of. This barrier must be able to provide both visibility and security without being much expensive. Existence of a concrete wall will undoubtedly provide security but at the same time visibility of the impending danger to the security personnel is compromised. A wall is usually rigid and costs a lot to repair, alter and replace. More over a wall can serve only the purpose stated above; it cannot be used as dead ends to stop vehicles. Also concrete walls occupy more space and are difficult to transport from place to place. A bollard pole with sufficient energy absorbing capability can be used, both, for the above stated reasons as well as a simple restraint at dead ends of a road to save lives. These are more versatile for the reason that they can be used as stationary or be motorized to serve the purpose. Also these provide pedestrians and cyclists through passage as well as restrict large vehicle from passing through. Three dimensional models of the bollard poles with various cross-sections are made and a study is done using Finite Element softwares such as LS-Dyna 970 to find the maximum energy the bollards can absorb and still be able to function normally. The bollards are made from two different materials and a study is made to see whether the material of the bollard is reason for bollard failure at high impact speeds.
Thesis (M.S.)--Wichita State University, Dept. of Mechanical Engineering.