Numerical and Experimental Analysis of Nonlinear Vibrational Response due to Pressure-Dependent Interface Stiffness

Nouira, Dorra; Tonazzi, Davide; Méziane, Anissa; Baillet, Laurent; Massi, Francesco

doi:10.3390/lubricants8070073

Cited by 7 publications

(2 citation statements)

References 31 publications

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“…Contact stiffness of conformal surface (flat) specimens has been evaluated by impact in [18] and by applying a static load focusing on the effect of roughness in [19]. The experimental data of normal force and deformation are fitted using nonlinear contact laws.…”

Section: Introductionmentioning

confidence: 99%

Tilting Pad Journal Bearing Ball and Socket Pivots: Experimental Determination of Stiffness

et al. 2022

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Tilting pad journal bearings (TPJB) are used in turbomachinery for their stability at high speeds. For design purposes, it is necessary to preliminarily investigate the turbomachine rotor dynamic behavior by simulation. The dynamic characteristics of all components must be known as precisely as possible and experimental validation of each single model is required. While a lot of work has been carried out on bearings, the ball-and-socket stiffness is still estimated by means of Hertzian formulas. Recently, some authors have used the finite element method, but it seems that nothing has been done experimentally to date. This paper describes the test rig designed to determine the stiffness of a TPJB ball-and-socket pivot by equipping the grippers of a tensile universal testing machine with specifically designed interfaces. A methodology for evaluating the stiffness from the experimental results is reported. Preliminary compression results are presented and compared with the analytical ones obtained using Hertz’s formula showing significant differences for the ball-and-socket conformal contact.

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Section: Introductionmentioning

confidence: 99%

Tilting Pad Journal Bearing Ball and Socket Pivots: Experimental Determination of Stiffness

et al. 2022

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“…In Ref. [11] Nouira et al have numerically and experimentally studied the propagation of elastic waves in a mechanical assembly that presents contact interfaces. Indeed, due to the interfacial roughness, the contact stiffness is nonlinear, often represented with a power-law model, which introduces higher-order harmonics into the system dynamical response.…”

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confidence: 99%

Interfacial Dissipative Phenomena in Tribomechanical Systems

Papangelo

2021

Lubricants

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Critical thresholds for mode-coupling instability in viscoelastic sliding contacts

2021

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Mode-coupling instabilities are known to trigger self-excited vibrations in sliding contacts. Here, the conditions for mode-coupling (or “flutter”) instability in the contact between a spherical oscillator and a moving viscoelastic substrate are studied. The work extends the classical 2-Degrees-Of-Freedom conveyor belt model and accounts for viscoelastic dissipation in the substrate, adhesive friction at the interface and nonlinear normal contact stiffness as derived from numerical simulations based on a boundary element method capable of accounting for linear viscoelastic effects. The linear stability boundaries are analytically estimated in the limits of very low and very high substrate velocity, while in the intermediate range of velocity the eigenvalue problem is solved numerically. It is shown how the system stability depends on externally imposed parameters, such as the substrate velocity and the normal load applied, and on contact parameters such as the interfacial shear strength $$\tau _{0}$$ τ 0 and the viscoelastic friction coefficient. In particular, for a given substrate velocity, there exist a critical shear strength $$\tau _{0,crit}$$ τ 0 , c r i t and normal load $$F_{n,crit}$$ F n , c r i t , which trigger mode-coupling instability: for shear stresses larger than $$\tau _{0,crit}$$ τ 0 , c r i t or normal load smaller than $$F_{n,crit}$$ F n , c r i t , self-excited vibrations have to be expected.

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Numerical and Experimental Analysis of Nonlinear Vibrational Response due to Pressure-Dependent Interface Stiffness

Cited by 7 publications

References 31 publications

Tilting Pad Journal Bearing Ball and Socket Pivots: Experimental Determination of Stiffness

Tilting Pad Journal Bearing Ball and Socket Pivots: Experimental Determination of Stiffness

Interfacial Dissipative Phenomena in Tribomechanical Systems

Critical thresholds for mode-coupling instability in viscoelastic sliding contacts

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