Transit Bus Design Effects Utilizing Improved Steel or Fiber Reinforced Composite Structures

A typical production transit bus with vertical pillars of small section size, low gauge and low strength steel, exhibits extensive lateral pillar side-sway collapse (matchboxing) in rollover impacts. This matchboxing allows rollover of the bus onto its roof. LS-DYNA simulations demonstrate that roof pillars of high strength steel or inexpensive E-glass fiber reinforced polymer (FRP) pultrusions can prevent matchboxing and arrest the rollover of the bus. However, for the same space envelope, pultruded FRP pillars can be at least 41% lighter than high strength steel square tubes exhibiting the same bending moment capacity.