Abstract: A bumper structure for absorbing a collision impact having a bumper, a bumper stay supporting the bumper component and a side member supporting the bumper stay via a bolts so as to be offset horizontally and downwardly relative to the bumper stay. The side member has a weakened portion opposite the mounting connection of the side member to the bumper stay, and has an extended portion extending from an end of the side member. The positions of the bumper stay, weakened area, and extended portion being such that the torque transferred to the weakened portion via the securing means is substantially equal and opposite to the torque transferred to the weakened portion via the extending portion, such that the side member is crushed into accordion-like pleats in the longitudinal direction to progressively absorb the impact.

Abstract: A method of determining the positions of beads, capable of determining appropriate positions easily. The method includes the steps of obtaining a buckling waveform on the member without any bead; analyzing the obtained buckling waveform to determine concave portions and convex portions of the buckling waveform; and determining the positions of the beads in accordance with the concave portions and the convex portions of the buckling waveform.