The final goal of this study is to construct safety structures for medical and human-car robots and moving equipments. This paper proposes a concept of the smart structure applied to them that has an ideal load-deflection curve for the safety design. An experimental study on the denting and bending of aluminum skin tubular beams and ways to control the load-deflection curves with various reinforcements and triggers was carried out as the first step of the goal. Experimental results on simply supported tubes show that a simple skin model for low load design and a double skin model for high load design have each ideal structural property considering from a viewpoint of high initial rigidity, peak-load control, high buffer efficiency and configuration reversibility. One of three kinds of reinforced skin tubes that are able to construct the ideal load-deflection curve with a ring-shaped trigger is proposed to be of most practical use for cantilever models.
