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Abstract: This paper develops a multi-stable lattice structure consisting of tri-stable lattice cell which is made by bistable laminates. The multi-stable lattice structure with N tri-stable lattice cells, which can exhibit 2 N stable states, is successfully designed and fabricated. The critical loads snapping lattice structure are investigated by the experimental and finite element techniques. The method to simulate the behaviors of contact and constraint between the neighboring bistable laminates are presented. The snap through process of multi-stable lattice structures among multiple states are numerically simulated and experimentally validated. The multiple stabilities highlight the potential to achieve a smooth shape variation in the large area multi-stable structures. [Copyright &y& Elsevier]

Bi-stable composite laminates with piezoelectric transducers have been shown to capture energy over a wide frequency range and deliver significantly greater energy than resonant devices. In this work, the influence of lay-up design on the performance of bi-stable piezoelectric energy harvester (BPEH) based on bi-stable hybrid symmetric laminate (BHSL) is analyzed and verified. The initial voltage induced by stable configuration and longitudinal curvature of BPEH with different lay-up and hybrid width were calculated and analyzed by a static finite element analysis. The lay-up can vary initial voltage and longitudinal in opposite directions, and hybrid width can adjust these two variables in the same direction. The strain variations of piezoelectric transducer between two stable configurations were also analyzed. The initial voltage of BPEH depends on strain variations in the two directions. And then the finite element results are verified by experiment. Three types of BPEH were manufactured and actuated by two methods to measure their output powers. These BPEHs presented different dynamic responses, and the output powers under different vibration modes were measured. The highest output power of BPEH in this work is 42.2 mW and the highest power density is 78.1 mW/cm 3 . [ABSTRACT FROM AUTHOR]

Bistable composite laminates have the potential advantage in the fields of wind energy harvesting and deformable wings, which involve many fluid–structure interaction issues. This paper presents the fluid–structure interaction analysis of a cantilevered bistable hybrid symmetrical laminate (BHSL) in the uniform wind. In this work, a finite element model based on the Lattice Boltzmann Method (LBM) is used to analyze the wind-induced response of the BHSL and its variations with respect to wind speed and laminate length. Then, the wind-induced vibration behavior of BHSL is verified by wind tunnel tests. The finite element analysis (FEA) results are in good agreement with the experimental results. The results show that as the wind speed increases, the BHSL transitions from a single-well vibration response to a cross-well vibration response. The wind-induced vibration analysis of BHSL will provide analytical methods for its application in deformable wings and energy harvesting for wind-induced vibration. [ABSTRACT FROM AUTHOR]

The resulting oscillation of bi-stable hybrid symmetric laminate could enable broadband energy harvesting via piezoelectric transduction. The aim of this work is to investigate its dynamic behaviors to provide the basis for designing broadband energy harvester. This paper proposes the dynamic analysis of this bi-stable laminate, focusing on the intra-well dynamics around its stable states and the inter-well dynamics between two stable states. Two types of stacking sequence are performed for this bi-stable laminate, and experimental testing with different harmonic excitations is carried out for each type of this bi-stable laminate. The strain responses at three positions are monitored to investigate the dynamic responses. A finite element model is also developed to analyze the static strain distribution and capture the dynamics. The results show that the laminates exhibit intra-well response under low-level excitation, and the inter-well response at a particular range frequency appears when excitation level increases. Different types of inter-well response mode involving the snap-through behavior are obtained in experiments, such as intermittent inter-well vibration and chaotic vibration. The presented results essentially highlight the need for considering the stacking sequence associated with the dynamics while designing the hybrid bi-stable symmetric laminate to obtain the desirable nonlinear response. [ABSTRACT FROM AUTHOR]

A bi-stable device is presented for simultaneous vibration absorption and energy harvesting by introducing the piezoelectric element into the bi-stable nonlinear energy sink (BNES), which is called the bi-stable piezoelectric absorber (BPZA). BPZA only consists of the cantilever bi-stable piezoelectric composite laminate (BPCL) and tip masses. This BPZA is a lightweight, simple and reliable structure since it does not need any external devices to maintain bistability. A finite element model (FEM) and an equivalent theoretical model are developed to model a harmonically excited linear oscillator coupled with BPZA. The Runge-Kutta method is used to solve the theoretical model numerically. The effects of the excitation amplitude, the tip mass of BPZA and the load resistance are considered on the vibration suppression efficiency and energy harvesting of BPZA. The results show adjusting these parameters can improve the vibration suppression efficiency and energy harvesting of BPZA. In addition, the experimental prototype is prepared and verifies the rightness of the finite element model and theoretical model. The BPZA achieves the goal of higher power density at lower acceleration and simultaneously has a good vibration absorption effect. Maximum power of 15.8mW is generated at an excitation frequency of 22 Hz and acceleration of 0.5 g. [ABSTRACT FROM AUTHOR]

The quasi-zero-stiffness (QZS) vibration isolator is usually composed of positive and negative stiffness elements in parallel. The negative stiffness element usually requires specific constraint boundaries to form negative stiffness characteristics, which cannot meet the lightweight design of spacecraft structures. So the bi-stable hybrid symmetric laminate (BHSL) is presented as a negative stiffness element. A finite element model (FEM) is developed to carry out static and dynamic analyses of this vibration isolator. An equivalent theoretical model is developed based on the restoring force–displacement curve of BHSL. The approximate analytical solutions and direct numerical solutions are obtained by employing the averaging method and the Runge-Kutta method, respectively. Different types of the steady-state response are obtained, namely the symmetrical multi-harmonic response, the asymmetric multi-harmonic response and the single-harmonic response. There exists a small gap between the analytical solutions and the Runge-Kutta solutions or the FEM results only at the low frequency excitation due to the super-harmonics. The displacement transmissibility is used to quantify the vibration isolation performance of this vibration isolator. The experiment is designed to verify the theoretical and FEM models from static and dynamic analysis perspectives. The results show adjusting geometric parameters and lay-up designs can improve the vibration isolation performance. [ABSTRACT FROM AUTHOR]