Bistable inclined beam connected in series for quasi-zero stiffness

This paper investigates a structure system that expresses stable and controllable quasi-zero stiffness in an integrated form, which is based on inclined bistable beams connected in series. This paper shows that interaction between the connected beams and their nonlinear axial stiffness always leads to a plateau trajectory in its force-displacement curve with very low tangential stiffness. The plateau part of the force-displacement occurs while each of the connected beam snaps through sequentially and ends when all of the beams are going though hardening behavior. A series of tests were conducted to validate this behavior. A numerical model capable of predicting the behavior is developed. Studies were performed based on the model for this kind of structure with different geometric configuration and details of coupling links. The results show that in addition to being able to achieve quasi-zero stiffness of an integrated structures, this kind of structure has increased initial stiffness and loading capacity compared with traditional bistable structures subjected to similar limitations of extreme strains.