Smart structures are mechanisms that react to changes of the physical and mechanical conditions of environment and are adaptable to their working conditions. There is a class of smart structures which do not have sensor systems and can be created using very simple mechanical mechanisms. In order to improve the overall performance of structures, their mechanical behavior is predefined to establish the best reaction to some conditions such as vibrations and impact forces. In this paper, in order to improve performance of bumper beam in collision, different mechanical behaviors has been employed such as two-linear smart behavior in the region where bumper and car are connected. LS-DYNA-V970 software has been used for simulating of collision and the most appropriate behavior has been identified. Results have shown that the most appropriate treatment for connections is the one which has higher initial stiffness where the structure becomes more flexible by increasing the collision force and its stiffness is reduced to prevent the failure of the bumper beam. Investigation of two-linear smart behavior in bumper connections and the displacement in which the stiffness changes showed that less displacement will result inbetter outcomes.
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