Effect Analysis of Sandwich Structures in Center Frame for Low-Floor Vehicle

초록

A low-floor vehicle has no steps to get on or get off the main cabin to provide the old and the handicapped with easy access. Korean government made a plan to subsidize (50% of bus price) to purchase about 10,000 low-floor buses for mobility enhancement of the handicapped, the old, the weak, children, passengers with their infants or old parents, and passengers with carts and strollers to use public transport until 2013. One of the important requirements derived from passengers, drivers, and operators was weight reduction to improve fuel efficiency and CO2 emission in comparison with conventional low-floor buses in service. For the desinged center frame, strength and stiffness were analyzed under the vertical concentrated load 9.81[kN] on the boundary condition that all corners of the center frame except passenger door location were fixed (welded). In other words, strength, vertical deflection, and torsion rigidity were compared when the composite material skin (glass fabric/epoxy resin) and aluminum honeycomb were installed and not installed in the center frame. The center frame with sandwich structures has about 56.1% reduced maximum stress (Von-Mises stress), about 40% reduced vertical deformation, and about 68.5% increaced torsion rigidity in comparison with the center frame without sandwich structures (steel structures were indentical to each other).