An experimental switchable stiffness device for shock isolation

Ledezma-Ramírez, Diego Francisco; Ferguson, N.S.; Brennan, M.J.

doi:10.1016/j.jsv.2012.06.010

Cited by 52 publications

(26 citation statements)

References 16 publications

(26 reference statements)

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“…On the other hand, lower stiffness affects vehicle handling. Referring to equation (22), desired stiffness settings for different values of the sprung mass are given in Table 4. Table 4 shows that for the given change in the sprung mass, the suspension stiffness needs to be varied by 31% (i.e.…”

Section: Design Of Real Size Variable Stiffness Systemmentioning

confidence: 99%

Analysis of suspension with variable stiffness and variable damping force for automotive applications

Jugulkar

Singh

Sawant

2016

Advances in Mechanical Engineering

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Passive shock absorbers are designed for standard load condition. These give better vibration isolation performance only for the standard load condition. However, if the sprung mass is lesser than the standard mass, comfort and road holding ability is affected. It is demonstrated that sprung mass acceleration increases by 50%, when the vehicle mass varies by 100 kg. In order to obtain consistent damping performance from the shock absorber, it is essential to vary its stiffness and damping properties. In this article, a variable stiffness system is presented, which comprises of two helical springs and a variable fluid damper. Fluid damper intensity is changed in four discrete levels to achieve variable stiffness of the prototype. Numerical simulations have been performed with MATLAB Simscape and Simulink which have been with experimentation on a prototype. Furthermore, the numerical model of the prototype is used in design of real size shock absorber with variable stiffness and damping. Numerical simulation results on the real size model indicate that the peak acceleration will improve by 15% in comparison to the conventional passive solution, without significant deterioration of road holding ability. Arrangement of sensors and actuators for incorporating the system in a vehicle suspension has also been discussed.

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Section: Design Of Real Size Variable Stiffness Systemmentioning

confidence: 99%

Analysis of suspension with variable stiffness and variable damping force for automotive applications

Jugulkar

Singh

Sawant

2016

Advances in Mechanical Engineering

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“…Ledezma has also recently presented a switchable stiffness strategy in two stages, namely, the control during a shock and the later stiffness switching to reduce residual vibrations. This study demonstrated theoretically and experimentally that reducing the stiffness for the duration of a shock reduces the peak response of the system [9,10].…”

Section: Introductionmentioning

confidence: 80%

Mathematical Modeling of a Transient Vibration Control Strategy Using a Switchable Mass Stiffness Compound System

Ledezma-Ramírez

Ferguson

Zamarripa

2014

Shock and Vibration

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A theoretical control strategy for residual vibration control resulting from a shock pulse is studied. The semiactive control strategy is applied in a piecewise linear compound model and involves an on-off logic to connect and disconnect a secondary mass stiffness system from the primary isolation device, with the aim of providing high energy dissipation for lightly damped systems. The compound model is characterized by an energy dissipation mechanism due to the inelastic collision between the two masses and then viscous damping is introduced and its effects are analyzed. The objective of the simulations is to evaluate the transient vibration response in comparison to the results for a passive viscously damped single degree-of-freedom system considered as the benchmark or reference case. Similarly the decay in the compound system is associated with an equivalent decay rate or logarithmic decrement for direct comparison. It is found how the compound system provides improved isolation compared to the passive system, and the damping mechanisms are explained.

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“…Moreover, it is important to mention the recent increased interest in variable and nonlinear stiffness strategies for control and isolation of shock produced vibration, demonstrating the feasibility and isolation performance of low dynamic nonlinear stiffness for high-level excitations. [11][12][13] Apart from the study of Guzman-Nieto et al, 9 to the knowledge of the authors, there is no published study dealing with the shock response of wire rope isolators.…”

Section: Ikmalmentioning

confidence: 99%

Experimental characterisation of dry friction isolators for shock and vibration

Tapia-González

Ledezma-Ramírez

2017

Journal of Low Frequency Noise, Vibration and Active Control

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Shock and vibration are a source of failures in harsh environments such as military, naval and aerospace applications; thus, the use of vibration isolators is extended. Cable isolators are known for their high-energy storage and dissipation properties making them suitable for shock isolation and low frequency vibration. Such isolators present nonlinear stiffness in different directions such as compression, roll and shear, as well as dry friction damping. Although their use is extended, the knowledge regarding their dynamic response under shock loading is very limited. This work presents an overview of the vibration and shock isolation performance of several cable isolators under axial loading. The main contribution of the paper is to investigate and discuss the shock response of the isolators when subjected to pulses of different durations, finding improved isolation performance when compared to an equivalent linear system. Furthermore, a mathematical model based on a Duffing oscillator is proposed as a first approximation, in order to reflect the nonlinear stiffness and predict the shock response, thus facilitating further design and selection of improved shock isolation systems.

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An experimental switchable stiffness device for shock isolation

Cited by 52 publications

References 16 publications

Analysis of suspension with variable stiffness and variable damping force for automotive applications

Analysis of suspension with variable stiffness and variable damping force for automotive applications

Mathematical Modeling of a Transient Vibration Control Strategy Using a Switchable Mass Stiffness Compound System

Experimental characterisation of dry friction isolators for shock and vibration

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