Side members are provided with beads that promote more effective absorption of crash energy in vehicle frontal collisions. In this work, finite element analysis was used to investigate a method of calculating the most effective beading position. First, it was found that an inelastic buckling mode as a numerical imperfection makes it possible to analyze the collapse behavior of beaded members. Second, a new method was developed for calculating the most effective beading position along the buckling mode of side members. When a side member is provided with beads according to this method, it collapses axially, enabling it to absorb crash energy more efficiently. It was also found that the buckling mode used as a numerical imperfection for determining the placement of beads should be calculated at the peak point of the load curve.