Topology simulation and contact mechanics of bifractal rough surfaces*

Borri, Claudio; Paggi, Marco

doi:10.1177/1350650116641017

Cited by 14 publications

(7 citation statements)

References 32 publications

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“…Figure 4b shows a variation in the slope of the PSD evaluated in this zone. Higher slope in the high frequency range usually is associated with a texturing of the surface at the nano-scale level as previously reported [35]. This so called bifractality suggests two different level of organization in the surface and the shift between the two regimes is located in correspondence of 1 nm lenghtscale.…”

Section: Morphological Characterizationsupporting

confidence: 73%

First Proof-of-Principle of Inorganic Lead Halide Perovskites Deposition by Magnetron-Sputtering

et al. 2019

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The present work reports the application of RF-magnetron sputtering technique to realize CsPbBr 3 70 nm thick films on glass substrate by means of a one-step procedure. The obtained films show highly uniform surface morphology and homogeneous thickness as evidenced by AFM and SEM investigations. XRD measurements demonstrate the presence of two phases: a dominant orthorhombic CsPbBr 3 and a subordinate CsPb 2 Br 5 . Finally, XPS data reveals surface bromine depletion respect to the stoichiometrical CsPbBr 3 composition, nevertheless photoluminescence spectroscopy results confirm the formation of a highly luminescent film. These preliminary results demonstrate that our approach could be of great relevance for easy fabrication of large area perovskite thin films. Future developments, based on this approach, may include the realization of multijunction solar cells and multicolor light emitting devices.

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Section: Morphological Characterizationsupporting

confidence: 73%

First Proof-of-Principle of Inorganic Lead Halide Perovskites Deposition by Magnetron-Sputtering

et al. 2019

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“…Theoretically, the FFT filtering method 5,[26][27][28][29][30] and the SRM 21,22,39 have the same aim: generating random series with the desired PSD. They construct complex Fourier coefficients, where the amplitude terms follow the desired PSD.…”

Section: Fft Filtering Methods and Srmmentioning

confidence: 99%

“…It turned out that the FFT filtering method reproduces the power-law PSD better than the other two methods. Müser et al, 9 Borri and Paggi, 30 and Zhang et al 15 used the FFT filtering method as well. Besides the FFT filtering method and the W-M function, the RMD is another common choice in studies, for example, Pei et al, 31 Bonari et al, 32 and Vakis et al 33 simulated fractal surfaces by the RMD for contact analysis.…”

Section: Introductionmentioning

confidence: 99%

Generating fractal rough surfaces with the spectral representation method

Wang

Azam

Wilson

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part J:

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The application of the spectral representation method in generating Gaussian and non-Gaussian fractal rough surfaces is studied in this work. The characteristics of fractal rough surfaces simulated by the spectral representation method and the conventional Fast Fourier transform filtering method are compared. Furthermore, the fractal rough surfaces simulated by these two methods are compared in the simulation of contact and lubrication problems. Next, the influence of low and high cutoff frequencies on the normality of the simulated Gaussian fractal rough surfaces is investigated with roll-off power spectral density and single power-law power spectral density. Finally, a simple approximation method to generate non-Gaussian fractal rough surfaces is proposed by combining the spectral representation method and the Johnson translator system. Based on the simulation results, the current work gives recommendations on using the spectral representation method and the Fast Fourier transform filtering method to generate fractal surfaces and suggestions on selecting the low cutoff frequency of the power-law power spectral density. Furthermore, the results show that the proposed approximation method can be a choice to generate non-Gaussian fractal surfaces when the accuracy requirements are not high. The MATLAB codes for generating Gaussian and non-Gaussian fractal rough surfaces are provided.

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“…It starts from the lower frequency, which is inversely correlated to the scan length q L = 2π L , up to a high measured frequency, related to the short-distance cut-off wavevector, defined by q s = 2π ∆ where ∆ refers to the sampling length. In fact, the radial PSD has a shape similar to the bi-fractal surfaces defined in [51]. The difference lies in the definition of the slopes of the linear regions.…”

Section: Pad Surface Characterizationmentioning

confidence: 95%

A Multi-Scale Investigation to Predict the Dynamic Instabilities Induced by Frictional Contact

Maaboudallah

Atalla

2023

Lubricants

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We propose a new variational formulation to model and predict friction-induced vibrations. The multi-scale computational framework exploits the results of (i) the roughness measurements and (ii) the micro-scale contact simulations, using the boundary element method, to enrich the contact zone of the macroscopic finite element model of rubbing systems with nominally flat contact boundaries. The resulting finite elements at the contact interface of the macroscopic model include (i) a modified normal gap and (ii) a micro-scale description of the contact law (i.e., pressure gap) derived by solving the frictionless contact problem on a rough surface indenting a rigid half-plane. The method is applied to a disc brake system to show its robustness in comparison with classical deterministic formulations. With respect to the traditional complex eigenvalues analysis, the proposed multi-scale approach shows that the inclusion of roughness significantly improves the results at low frequencies. In this panorama, any improvement of dynamic instabilities predictions should be based on an uncertainty analysis incorporating roughness combined with other parameters such as friction coefficient and shear moduli of the pads, rather than on roughness itself.

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Topology simulation and contact mechanics of bifractal rough surfaces*

Cited by 14 publications

References 32 publications

First Proof-of-Principle of Inorganic Lead Halide Perovskites Deposition by Magnetron-Sputtering

First Proof-of-Principle of Inorganic Lead Halide Perovskites Deposition by Magnetron-Sputtering

Generating fractal rough surfaces with the spectral representation method

A Multi-Scale Investigation to Predict the Dynamic Instabilities Induced by Frictional Contact

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