Effect of Surface Roughness on Adhesion and Friction of Microfibers in Side Contact

Author(s):  
Mircea Teodorescu ◽  
Carmel Majidi ◽  
Homer Rahnejat ◽  
Ronald S. Fearing

A multi-scale mathematical model is used to study the effect of surface roughness on the adhesion and friction of microfibers engaged in side contact. Results are compared to closed-form analytic approximations derived from linear elastic contact mechanics.


2021 ◽  
Vol 69 (4) ◽  
Author(s):  
Jamal Choudhry ◽  
Andreas Almqvist ◽  
Roland Larsson

AbstractA multi-scale flash temperature model has been developed and validated against existing work. The core strength of the proposed model is that it can be adapted to predict flash contact temperatures occurring in various types of sliding systems. In this paper, it is used to investigate how different surface roughness parameters affect the flash temperatures. The results show that for decreasing Hurst exponents as well as increasing values of the high-frequency cut-off, the maximum flash temperature increases. It was also shown that the effect of surface roughness does not influence the average interface temperature. The model predictions were validated against data from an experiment conducted in a pin-on-disc machine. This also showed the importance of including a wear model when simulating flash temperature development in a sliding system.



2003 ◽  
Author(s):  
Renato Buzio ◽  
Karolina Malyska ◽  
Zygmunt Rymuza ◽  
Corrado Boragno ◽  
Francesco Buatier de Mongeot ◽  
...  

The non-stationary character of roughness is a widely recognized property of surface morphology and suggests modelling several solid surfaces by fractal geometry. In the field of contact mechanics this demands for novel investigations attempting to clarify the role of multi-scale roughness during physical contact. Here we propose an experimental investigation of the mechanical response of SrTiO3 substrates probed by a commercial nanoindentor. Load-displacement curves have been acquired respectively on well-defined crystalline surfaces and on mechanically lapped surfaces. We observe the first-loading cycles to be considerably affected by surface roughness whenever the penetration depth is kept below the interface width. The obtained results are analyzed within an elasto-plastic deformation model for fractal surfaces and a picture is developed to describe the deformation process with respect to surface roughness and structural parameters.



Author(s):  
Tong Zhang ◽  
Xiaojun Liu ◽  
Yan Zhang ◽  
Jiaxin Ye ◽  
Wei Wang ◽  
...  

The contact geometry of rough surfaces markedly affects the functional properties such as sealing and lubrication. The effect of surface roughness on the percolation characteristic of elastic contact was studied. The elastic contact of randomly rough surfaces with a glass plate was performed using four different surface roughnesses of silicone rubber blocks as specimens. The results illustrate that the percolation threshold was significantly affected by the valley morphology of a surface. The increase in depth and void volume of valleys improved the connectivity between valleys, but impeded the coalescence of contact clusters, resulting in the extinction of the spanning void cluster allowing fluid flow when the relative contact area was large. Furthermore, the critical pressure and connectivity at the percolation threshold were related to the maximum peak height and autocorrelation length of a surface, respectively.



Shinku ◽  
1987 ◽  
Vol 30 (10) ◽  
pp. 793-798 ◽  
Author(s):  
Masao HIRASAKA ◽  
Masao HASHIBA ◽  
Toshiroh YAMASHINA




2018 ◽  
Vol 00 (1) ◽  
pp. 109-118
Author(s):  
Enas Y. Abdullah ◽  
◽  
Naktal Moid Edan ◽  
Athraa N. Kadhim ◽  
◽  
...  


2002 ◽  
pp. 337-378 ◽  
Author(s):  
Jozef Telega ◽  
Wlodzimierz Bielski

The aim of this contribution is mainly twofold. First, the stochastic two-scale convergence in the mean developed by Bourgeat et al. [13] is used to derive the macroscopic models of: (i) diffusion in random porous medium, (ii) nonstationary flow of Stokesian fluid through random linear elastic porous medium. Second, the multi-scale convergence method developed by Allaire and Briane [7] for the case of several microperiodic scales is extended to random distribution of heterogeneities characterized by separated scales (stochastic reiterated homogenization). .



2021 ◽  
pp. 096739112110055
Author(s):  
Gunce Ozan ◽  
Meltem Mert Eren ◽  
Cansu Vatansever ◽  
Ugur Erdemir

Surface sealants are reported to ensure surface smoothness and improve the surface quality of composite restorations. These sealants should also reduce the bacterial adhesion on composite surfaces however, there is not much information regarding their performance on bulk-fill composite materials. The aim of this study was to evaluate the effect of surface sealant application on surface roughness and bacterial adhesion of various restorative materials. Disc-shaped samples were prepared from a compomer, a conventional composite and three bulk-fill composites. Specimens of each group were divided into two groups (n = 9): with/without surface sealant (Biscover LV, [BLV]). Surface roughness values were examined by profilometry and two samples of each group were examined for bacterial adhesion on a confocal laser scanning microscope (CLSM). Bacterial counts were calculated by both broth cultivation and microscopic images. Results were analyzed with one-way ANOVA and Bonferroni/Dunn tests. Following the BLV application, there was a decrease in the surface roughness values of all groups however, only Tetric N-Ceram Bulk and Beautifil-Bulk groups showed significantly smoother surfaces (p < 0.001). There were no significant differences among material groups without BLV application. Evaluating bacterial adhesion after BLV application, conventional composite had the lowest values among all followed by the compomer group. Beautifil-Bulk had significantly the highest bacterial adhesion (p < 0.05), followed by Tetric N-Ceram Bulk group. Without BLV application, there was no significant difference among bacterial adhesion values of groups (p > 0.05). CLSM images showed cell viability in groups. Bulk-fill composites showed higher bacterial adhesion than conventional composite and compomer materials. The surface sealant was found to be highly effective in lowering bacterial adhesion, but not so superior in smoothing the surfaces of restorative materials. So, surface sealants could be used on the restorations of patients with high caries risk.



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