Force and displacement transmissibility of a nonlinear isolator with high-static-low-dynamic-stiffness

Carrella, A.; Brennan, M.J.; Waters, T.P.; Lopes, Véra Lucia Rocha

doi:10.1016/j.ijmecsci.2011.11.012

Cited by 483 publications

(202 citation statements)

References 12 publications

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“…Note that this is not a severe restriction as the displacements of a practical system are unlikely to be 20% of the length of the horizontal spring. It is also assumed that the maximum value of the excitation force is such that analytical results are valid [12,23]. Using Taylor expansion, (1a) and (1b) and (2) can be approximated by…”

Section: Formalizationsmentioning

confidence: 99%

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Power Flow in a Two‐Stage Nonlinear Vibration Isolation System with High‐Static‐Low‐Dynamic Stiffness

Shao

Ding

2018

Shock and Vibration

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The manuscript concerns the power flow characterization in a two-stage nonlinear vibration isolator comprising three springs, which are configured so that each stage of the system has a high-static-low-dynamic stiffness. To demonstrate the distinction of evaluation for vibration isolation using power flow, force transmissibility is used for comparison. The dynamic behavior of the isolator subject to harmonic excitation, however, is of interest here. The harmonic balance method (HBM) could be used to analyze the frequency response curve (FRC) of the strong nonlinear vibration system. A suggested stability analysis to distinguish the stable and the unstable HBM solutions is described. Increasing both upper and lower nonlinear stiffness could bend the first resonant peak to the left. The isolation range in the power and the force transmissibility plot could be extended to the lower frequencies when the nonlinear stiffness is increased, but the rate of roll-off for the power transmissibility is twice the rate for the force transmissibility at each horizontal stiffness setting. An explanation for this phenomenon is given in the paper.

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Section: Formalizationsmentioning

confidence: 99%

“…Vibration isolation with high-static-low-dynamic stiffness (HSLDS) was widely concerned [10][11][12][13][14][15][16][17][18][19][20][21]. For that, the linear isolation can only occur when the excitation frequency is above √ 2× natural frequency of the system.…”

Section: Introductionmentioning

confidence: 99%

Power Flow in a Two‐Stage Nonlinear Vibration Isolation System with High‐Static‐Low‐Dynamic Stiffness

Shao

Ding

2018

Shock and Vibration

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“…Carrella et al [9] presents analysis of a similar geometrical spring arrangement, with the aim of achieving near zero stiffness at equilibrium, known as Quasi Zero Stiffness (QZS). In a more recent paper, Carrella et al idealised the dynamic response of this mechanism as a Duffing oscillator, demonstrating important differences between its force transmissibility and motion transmissibility [10]. Kovacic et al [11] also proposed oblique spring arrangements, but with nonlinear springs to reduce the variability in dynamic stiffness with displacement from equilibrium.…”

Section: Prior Work On Hslds Isolation Mountsmentioning

confidence: 99%

Relieving the effect of static load errors in nonlinear vibration isolation mounts through stiffness asymmetries

Shaw

Neild²,

Friswell

2015

Journal of Sound and Vibration

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High Static Low Dynamic Stiffness (HSLDS) mounts consist of nonlinear springs that support a high static load with low static displacement, whilst maintaining locally low stiffness near equilibrium, to give a low natural frequency and consequently good isolation properties. Recent analysis has investigated such devices when the force-displacement relationship is an odd function about the equilibrium position, and analysed the consequences of different shapes of these functions. However many devices that have the HSLDS characteristic do not meet the assumptions of this analysis, in that the force-displacement relationship is generally asymmetric about equilibrium. Furthermore, even devices that do meet this assumption may be subject to significant adjustment error, particularly in the context of air vehicles where manoeuvres such as banked turns can cause an apparent variation in gravitational acceleration, and a consequent variation in the weight of the payload. This change in static load moves the payload away from its intended region of low stiffness. The current paper provides analysis of these situations, and shows that the performance of a mount with a symmetric stiffness-displacement relationship is highly sensitive to errors in the static loading. It is then shown that a mount with an asymmetric stiffnessdisplacement function can offer significant performance advantages when there are adjustment errors in the loading of the mount.

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“…However, most of them are passive mechanism whose negative stiffness cannot be adjusted. For example, a common way to obtain negative stiffness in the research papers [5,6] is using two oblique mechanical coil springs. With these two precompressed coil springs, a negative stiffness can be got in vertical direction but cannot be adjusted as there is no adjustment mechanism.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the isolator with magnets is not suitable for vibration isolation at high temperature. Unlike the way of using the electromagnets, Xu and Sun [21] proposed a theoretical model with adjustable negative stiffness by applying actuators to the traditional negative stiffness mechanism shown in [5,6] to change the prestressed length of oblique springs. However, this regulating mode of the negative stiffness may be not very suitable for the practical application due to the empty trip phenomenon.…”

Section: Introductionmentioning

confidence: 99%

A New Approach to Achieve Variable Negative Stiffness by Using an Electromagnetic Asymmetric Tooth Structure

Han

Liu

et al. 2018

Shock and Vibration

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Traditional passive nonlinear isolators have been paid much attention in recent literatures due to their excellent performance compared to linear vibration isolators. However, they are incapable of dealing with varying conditions such as changing excitation frequency due to the nonadjustable negative stiffness. To solve this drawback, a new approach to achieve variable negative stiffness is proposed in this paper. The negative stiffness is realized by an electromagnetic asymmetric magnetic tooth structure and can be changed by adjusting the magnitude of the input direct current. Analytical model of the electromagnetic force is built and simulations of magnetic field are conducted to validate the negative stiffness. Then the EATS is applied to vibration isolation and an electromagnetic vibration isolator is designed. Finally, a series of tests are conducted to measure the negative stiffness experimentally and confirm the effect of the EATS in vibration isolation.

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Force and displacement transmissibility of a nonlinear isolator with high-static-low-dynamic-stiffness

Cited by 483 publications

References 12 publications

Power Flow in a Two‐Stage Nonlinear Vibration Isolation System with High‐Static‐Low‐Dynamic Stiffness

Power Flow in a Two‐Stage Nonlinear Vibration Isolation System with High‐Static‐Low‐Dynamic Stiffness

Relieving the effect of static load errors in nonlinear vibration isolation mounts through stiffness asymmetries

A New Approach to Achieve Variable Negative Stiffness by Using an Electromagnetic Asymmetric Tooth Structure

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