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This paper develops a new bi-stable nonlinear energy sink (BNES) only consisting of the cantilever bi-stable hybrid symmetric laminate (BHSL) and tip masses. This BNES has advantages of light weight, simple and reliable structure, since it does not need external devices or magnets to maintain its bi-stable characteristic. A finite element model (FEM) is developed to perform static and dynamic analyses of a harmonically excited linear oscillator coupled with BNES. An equivalent theoretical model is developed to model the coupled system based on the relationship between the restoring force and the displacement of BHSL. The Runge-Kutta method is used to perform direct numerical solutions. Different types of the steady-state response for BNES contain the local and global periodic motions, the local and global strongly modulated responses and chaos, while the primary object exhibits the periodic motion and the strongly modulated response. The effects of the excitation amplitude, the tip mass of BNES, the lay-up design and the length of BHSL are considered on the dynamic responses and vibration suppression efficiency of BNES. The results show adjusting these parameters and lay-up designs can improve the vibration suppression efficiency of BNES. In addition, the experimental prototype is prepared and verifies the rightness of the finite element model and theoretical model. [ABSTRACT FROM AUTHOR]

The mechanical behaviors of the twisted profiled textile composite structures with different twist angles were studied by using a novel cantilever beam experiment. The strain distributions on the upper surface of the specimen were monitored by using DIC. Several strain gauges were located at different positions on the lower surface of the specimen. With the increase of cantilever load, the deformation of twisted specimen experienced from the initial torsion to the bending-torsion coupling deformation. The effects of twist angles on stiffness and strength of the twisted composite structures were analyzed. The stiffness distributions of the twisted composite structures are determined by using the finite element analysis (FEA) combining with the experimental results. There is a cubic polynomial function relationship between the macroscopic local twisted angle and the local material stiffness. The stiffness and strength of 135° twisted specimen are higher than that of 45°twisted specimen. The dominant failure mode was the compression fracture at the edge of the lower right corner of the twisted specimen. This study can be helpful of guiding the design of the twisted profiled textile composites structures. [ABSTRACT FROM AUTHOR]