A system for absorbing energy to attenuate a force caused by an impact includes: an elongated tubular element; a fixed ring having a plurality of wedge-shaped flanges associated with the elongated tubular element; and a mobile element associated with the fixed ring. In response to movement toward the wedge-shaped flanges, the mobile element interacts with the wedge-shaped flanges, which in turn interact with the elongated tubular element so as to trigger collapse of the elongated tubular element.