Abstract: A bus front framework structure design was proposed to improve the bus structure crashworthiness,
with a finite element model established based on a type of bus in production in China. Pendulum tests were
simulated numerically referring to the requirements of European regulation ECE-R29. The transformations
and accelerations for a bus front framework in crash were calculated using nonlinear explicit finite element
code LS-DYNA. An orthogonal design was applied to optimizing the frame absorption efficiency for different
materials and thicknesses. The results show that the bus-framework thin-walled structures absorb and dissipate
the kinetic energy of the pendulum while keeping the deceleration level under the tolerable limit; and that the
improved scheme has better absorption efficiency with fewer experiments for structure design than conventional
schemes.

Key words: bus, structure crashworthiness, pendulum test, framework structure design, orthogonal design, absorption efficiency