Design Using Modal Behavior Factors

Abstract Different numerical sub-structuring techniques for the representation of tire modal behavior have been developed in the past 20 years. By using these numerical techniques reduced dynamic models are obtained which can not only be used for internal studies but also be provided to the automobile industry and linked to reduced dynamic vehicle models in order to optimize the coupled vehicle-tire response for noise vibration and harshness purposes. Two techniques that have been developed in a custom-made finite element code are presented: 1) the component mode synthesis type models for which the wheel center interface is free and 2) the Craig and Bampton type models for which the wheel center interface is fixed. For both techniques the interface between the tire and the ground is fixed. The choice of fixed or free wheel center boundary condition is arbitrary. In this paper we will compare the formulation of these two numerical methods, and we will show the equivalency of both methods by showing the results obtained in terms of frequency and transfer functions. We will show that the two methods are equivalent in principle and the reduced dynamic models can be converted from one to the other. The advantages-disadvantages of each method will be discussed along with a comparison with experimentally obtained results.

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Impact of Cross-Tie Properties on the Modal Behavior of Cable Networks on Cable-Stayed Bridges

The Scientific World JOURNAL ◽

10.1155/2015/989536 ◽

2015 ◽

Vol 2015 ◽

pp. 1-14 ◽

Cited By ~ 3

Author(s):

Javaid Ahmad ◽

Shaohong Cheng ◽

Faouzi Ghrib

Keyword(s):

Analytical Model ◽

Design Parameters ◽

Reference Base ◽

Cable Network ◽

Cable Networks ◽

Modal Behavior ◽

Stiffness And Damping ◽

Main Cables ◽

The Impact ◽

Selection Of

Dynamic behaviour of cable networks is highly dependent on the installation location, stiffness, and damping of cross-ties. Thus, these are the important design parameters for a cable network. While the effects of the former two on the network response have been investigated to some extent in the past, the impact of cross-tie damping has rarely been addressed. To comprehend our knowledge of mechanics associated with cable networks, in the current study, an analytical model of a cable network will be proposed by taking into account both cross-tie stiffness and damping. In addition, the damping property of main cables in the network will also be considered in the formulation. This would allow exploring not only the effectiveness of a cross-tie design on enhancing the in-plane stiffness of a constituted cable network, but also its energy dissipation capacity. The proposed analytical model will be applied to networks with different configurations. The influence of cross-tie stiffness and damping on the modal response of various types of networks will be investigated by using the corresponding undamped rigid cross-tie network as a reference base. Results will provide valuable information on the selection of cross-tie properties to achieve more effective cable vibration control.

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Flexural Vibrations of an Elastic Plate With Two Symmetric Viscoelastic Coatings

Journal of Applied Mechanics ◽

10.1115/1.3607622 ◽

1967 ◽

Vol 34 (1) ◽

pp. 187-194

Author(s):

Paul Hertelendy ◽

Werner Goldsmith

Keyword(s):

Composite Plate ◽

Flexural Vibration ◽

Complex Shear Modulus ◽

Viscous Effects ◽

Approximate Methods ◽

Linear Viscoelastic Material ◽

Complex Shear ◽

Linear Viscoelastic ◽

Modal Behavior ◽

Viscoelastic Coatings

The flexural-vibration characteristics of a symmetric, doubly infinite composite plate consisting of two outer layers of a linear viscoelastic material bonded to an elastic core have been examined, the viscous effects in the coating being represented by a complex shear modulus. Calculations of the dispersive and damping effects have been obtained for the lowest three modes by an extension of the exact Rayleigh-Lamb equations. Loss factors of the lowest modes have also been evaluated by two readily computed approximate methods; the results have been compared with those from the exact solution. The material constants were chosen to be representative of a high-polymer coating and an aluminum core. The modal behavior of the systems and coupling effects are discussed.

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