scholarly journals Nonlinear dynamic response of a Negative Stiffness-Shape Memory Alloy isolation system

2021 ◽  
Author(s):  
Andrea Salvatore ◽  
Biagio Carboni ◽  
Walter Lacarbonara
Keyword(s):  
Shape Memory Alloy ◽  
Dynamic Response ◽  
Shape Memory ◽  
Nonlinear Dynamic ◽  
Vibration Isolation ◽  
Extensive Study ◽  
Negative Stiffness ◽  
Response Curves ◽  
Nonlinear Dynamic Response ◽  
Isolation System

Abstract The negative stiffness exhibited by bi-stable mechanisms together with tunable hysteresis in the context of vibration isolation devices can enhance the dynamic resilience of a structure. The effects of negative stiffness and shape memory alloy (SMA) damping in base-isolated structures are here explored by carrying out an extensive study of the nonlinear dynamic response via pathfollowing, bifurcation analysis, and time integration. The frequency-response curves of the isolated structure, with and without the negative stiffness contribution, are numerically obtained for different excitation amplitudes to construct the acceleration and displacement transmissibility curves. The advantages of negative stiffness, damping augmentation and reduced accelerations and displacements transmissibility, as well as the existence of rich bifurcation scenarios giving rise to quasi-periodicity and synchronization, are extensively illustrated.

scholarly journals Nonlinear dynamic response of an isolation system with superelastic hysteresis and negative stiffness

2021 ◽  
Author(s):  
Andrea Salvatore ◽  
Biagio Carboni ◽  
Walter Lacarbonara
Keyword(s):  
Dynamic Response ◽  
Nonlinear Dynamic ◽  
Vibration Isolation ◽  
Time Integration ◽  
Extensive Study ◽  
Negative Stiffness ◽  
Response Curves ◽  
Nonlinear Dynamic Response ◽  
Isolation System ◽  
Isolated Structures

AbstractThe negative stiffness exhibited by bi-stable mechanisms together with the tunable superelasticity offered by shape memory alloy (SMA) wires can enhance the dynamic resilience of a structure in the context of vibration isolation. The effects of negative stiffness and superelastic damping in base-isolated structures are here explored by carrying out an extensive study of the nonlinear dynamic response via pathfollowing, bifurcation analysis, and time integration. The frequency-response curves of the isolated structure, with and without the negative stiffness contribution, are numerically obtained for different excitation amplitudes to construct the acceleration and displacement transmissibility curves. The advantages of negative stiffness, such as damping augmentation and reduced acceleration/displacement transmissibility, as well as the existence of rich bifurcation scenarios toward quasi-periodicity and chaos, are discussed.

Nonlinear Dynamic Response of an Isolation System With Negative Stiffness and Shape Memory-Based Damping

2020 ◽  
Author(s):  
Andrea Salvatore ◽  
Biagio Carboni ◽  
Walter Lacarbonara
Keyword(s):  
Shape Memory ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Excitation Amplitude ◽  
Negative Stiffness ◽  
Response Curves ◽  
Nonlinear Dynamic Response ◽  
Isolation System ◽  
Hysteretic Damping ◽  
Different Levels

Abstract The negative stiffness offered by bi-stable mechanisms can improve the dynamic performance of a structure. In this work the effects of adding negative stiffness and shape memory alloy (SMA) damping in base-isolated structures are explored through the study of the stationary response for different values of negative stiffness and SMA hysteretic damping ratio. The frequency response curves of the isolated structure, with and without the negative stiffness contribution, are numerically obtained for different levels of excitation amplitude in order to evaluate the acceleration and displacement transmissibility curves. The benefits of negative stiffness, damping amplification and reduced transmissibility of accelerations and displacements, as well as the existence of dynamic instabilities, are illustrated.

Analysis of Nonlinear Dynamic Response of Wind Turbine Blade Under Fluid–Structure Interaction and Turbulence Effect

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Jianping Zhang ◽  
Kaige Zhang ◽  
Aixi Zhou ◽  
Tingjun Zhou ◽  
Danmei Hu ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Nonlinear Dynamic ◽  
Fluid Structure Interaction ◽  
Wind Turbine Blade ◽  
Response Curves ◽  
Nonlinear Dynamic Response ◽  
Structure Interaction ◽  
Turbulence Effect

In this paper, the entity model of a 1.5 MW offshore wind turbine blade was built by Pro/Engineer software. Fluid flow control equations described by arbitrary Lagrange–Euler (ALE) were established, and the theoretical model of geometrically nonlinear vibration characteristics under fluid–structure interaction (FSI) was given. The simulation of offshore turbulent wind speed was achieved by programming in Matlab. The brandish displacement, the Mises stress distribution and nonlinear dynamic response curves were obtained. Furthermore, the influence of turbulence and FSI on blade dynamic characteristics was studied. The results show that the response curves of maximum brandish displacement and maximum Mises stress present the attenuation trends. The region of the maximum displacement and maximum stress and their variations at different blade positions are revealed. It was shown that the contribution of turbulence effect (TE) on displacement and stress is smaller than that of the FSI effect, and its extent of contribution is related to the relative span length. In addition, it was concluded that the simulation considering bidirectional FSI (BFSI) can reflect the vibration characteristics of wind turbine blades more accurately.

Nonlinear Dynamic Response of Hysteretic Wire Ropes: Modeling and Experiments

2018 ◽  
Author(s):  
Andrea Arena ◽  
Biagio Carboni ◽  
Walter Lacarbonara
Keyword(s):  
Dynamic Response ◽  
Frequency Response ◽  
Nonlinear Dynamic ◽  
Wire Rope ◽  
Hysteretic Behavior ◽  
Response Curves ◽  
Nonlinear Dynamic Response ◽  
Wire Ropes ◽  
Tip Mass ◽  
Constitutive Parameters

The nonlinear dynamic response of short cables with a tip mass subject to base excitations and undergoing primary resonance is investigated via experimental tests and by employing an ad hoc nonlinear mechanical model. The considered cables are made of several strands of steel wires twisted into a helix forming composite ropes in a pattern known as ‘laid ropes’. Such short span ropes exhibit a hysteretic behavior due to the inter-wire frictional sliding. A nonlinear one-dimensional (1D) continuum model based on the geometrically exact Euler-Bernoulli beam theory is conveniently adapted to describe the cable dynamic response. The Bouc-Wen law of hysteresis is incorporated in the moment-curvature constitutive relationship to reproduce the hysteretic behavior of short steel wire ropes subject to flexural cycles. The frequency response curves show a pronounced softening nonlinearity induced by hysteresis and inertia nonlinearity as confirmed by the experimental data acquired on a wire rope with a tip mass excited at its base by a shaker. The experimental nonlinear resonance response will be exploited to identify the constitutive parameters of the wire rope that best fit the frequency response curves at various forcing amplitudes.

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