Scale effects on the attachment pads and friction forces in syrphid flies (Diptera, Syrphidae)

2001 ◽  
Vol 204 (8) ◽  
pp. 1421-1431 ◽  
Author(s):  
S. Gorb ◽  
E. Gorb ◽  
V. Kastner
Keyword(s):  
Body Mass ◽  
Friction Force ◽  
Contact Area ◽  
Scale Effects ◽  
Real Contact Area ◽  
Resistance Force ◽  
Friction Forces ◽  
The Real ◽  
Frictional Properties ◽  
Real Contact

To test the role of constructional and dimensional factors in the generation of friction force by systems of setose attachment pads, six species of syrphid fly (Platycheirus angustatus, Sphaerophoria scripta, Episyrphus balteatus, Eristalis tenax, Myathropa florea and Volucella pellucens) were studied using light and scanning electron microscopy. Flies were selected according to their various body mass and attachment pad dimensions. Such variables as pad area, setal density, the area of a single setal tip and body mass were individually measured. A centrifugal force tester, equipped with a fibre-optic sensor, was used to measure the friction forces of the pads on a smooth horizontal surface made of polyvinylchloride. Friction force, which is the resistance force of the insect mass against the sum of centrifugal and tangential forces, was greater in heavier insects such as Er. tenax, M. florea and V. pellucens. Although lighter species generated lower frictional forces, the acceleration required to detach an insect was greater in smaller species. The area of attachment pads, setal tip area and setal density differed significantly in the species studied, and the dependence of these variables on body mass was significant. The frictional properties of the material of the setal tips were not dependent on the dimensions of the fly species. Similar results were obtained for the frictional properties of the pulvillus as a whole. Thus, the properties of the secretion and the mechanical properties of the material of the setal tips are approximately constant among the species studied. It is concluded that differences in friction force must be related mainly to variations in the real contact area generated by the pad on the smooth surface. The real contact area can be estimated as the summed area of the broadened setal tips of the pad in contact with the surface. The real contact area depends on such morphological variables as setal density and the area of a single setal tip. Although individual variables vary among flies with different dimensions, they usually compensate such that smaller setal tip area is partially compensated for by higher setal density.

Influence of Paper Lint on Friction and Wear of Rubber Rollers

2018 ◽  
Author(s):  
Yosuke Tsukiyama ◽  
Isami Nitta
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Contact Area ◽  
Friction And Wear ◽  
Surface Contamination ◽  
Real Contact Area ◽  
The Real ◽  
Real Contact ◽  
Different Types

This paper deals with the influence of surface contamination on the frictional mechanisms of rubber rollers. The contamination which adhered on the rollers after feeding many sheets of papers is one of the predominant causes of paper jams. However, the mechanism has not been understood. The purpose of this paper is to clarify the relationships between the friction force and the real contact area of papers and contaminated rubber rollers. Carrying out paper feeding tests by using a commercial multifunction peripheral, we tested different types of papers produced by different manufacturers. The tests have been done with combinations of different manufacturer’s papers and different kinds of roller materials. Observations of the real contact area clarified that the roller surfaces covered with paper powders or lint reduces the friction coefficient.

scholarly journals Relationship between the real contact behavior and tribological characteristics of cotton fabric

Friction ◽  
2020 ◽  
Author(s):  
Rongxin Chen ◽  
Jiaxin Ye ◽  
Wei Zhang ◽  
Jiang Wei ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Contact Area ◽  
Dynamic Change ◽  
Tribological Characteristics ◽  
Real Contact Area ◽  
Cotton Fibers ◽  
Friction Behavior ◽  
Contact Behavior ◽  
The Real ◽  
Real Contact

Abstract The tribological characteristics of cotton fibers play an important role in engineering and materials science, and real contact behavior is a significant aspect in the friction behavior of cotton fibers. In this study, the tribological characteristics of cotton fibers and their relationship with the real contact behavior are investigated through reciprocating linear tribotesting and real contact analysis. Results show that the friction coefficient decreases with a general increase in load or velocity, and the load and velocity exhibit a co-influence on the friction coefficient. The dynamic change in the real contact area is recorded clearly during the experiments and corresponds to the fluctuations observed in the friction coefficient. Moreover, the friction coefficient is positively correlated with the real contact area based on a quantitative analysis of the evolution of friction behavior and the real contact area at different loads and velocities. This correlation is evident at low velocities and medium load.

An Observation Method of Real Contact Area during PVA Brush Scrubbing

2018 ◽  
Vol 282 ◽  
pp. 73-76 ◽  
Author(s):  
Toshiyuki Sanada ◽  
Masanao Hanai ◽  
Akira Fukunaga ◽  
Hirokuni Hiyama
Keyword(s):  
Contact Area ◽  
Contact Condition ◽  
Real Contact Area ◽  
Led Light ◽  
The Real ◽  
Real Contact ◽  
Observation Method

In the post CMP cleaning, the contact condition between PVA brush and surface is very important. In this study, we observed the real contact area between a brush and surface using a collimating LED light and prism. As a result, we found that the real contact area increases with increasing the brush compression. In addition, we also found that the real contact area decreases when the brush starts to move, and the brush was locally compressed due to its deformation.

scholarly journals A 3D study of the contact surface developed by the contact between the tires and the structural pavements

Exacta ◽  
2009 ◽  
Vol 6 (2) ◽  
pp. 197-208
Author(s):  
Alex Alves Bandeira ◽  
Rita Moura Fortes ◽  
João Virgílio Merighi
Keyword(s):  
Finite Element ◽  
Contact Mechanics ◽  
Contact Area ◽  
Augmented Lagrangian Method ◽  
Numerical Results ◽  
Real Contact Area ◽  
The Real ◽  
Real Contact ◽  
Commercial Program ◽  
Contact Surfaces

The basic aim in this work is to present a new technique to analyze the contact surfaces developed by the contact between the tires and the structural pavements by numerical simulations, using 3D finite element formulations with contact mechanics. For this purpose, the Augmented Lagrangian method is used. This study is performed just putting the tires on the structural pavement. These tires and the structural pavement are discretized by finite elements under large 3D elastoplastic deformation. The real loads (of aircrafts, trucks or cars) are applied directly on each tire and by contact mechanics procedures, the real contact area between the tires and the pavement surface is computed. The penetration conditions and the contact interfaces are investigated in details. Furthermore, the pressure developed at the contact surfaces is automatically calculated and transferred to the structural pavement by contact mechanics techniques. The purpose of this work research is to show that the contact area is not circular and the finite element techniques can calculate automatically the real contact area, the real geometry and its stresses and strains. In the end of this work, numerical results in terms of geometry, stress and strain are presented and compared to show the ability of the algorithm. These numerical results are also compared with the numerical results obtained by the commercial program ANSYS.

scholarly journals Measurement of Real Contact Area for Rough Metal Surfaces and the Distinction of Contribution From Elasticity and Plasticity

2020 ◽  
Vol 143 (7) ◽  
Author(s):  
Lei-Tao Li ◽  
Xuan-Ming Liang ◽  
Yu-Zhe Xing ◽  
Duo Yan ◽  
Gang-Feng Wang
Keyword(s):  
Contact Area ◽  
Rough Surfaces ◽  
Normal Load ◽  
Real Contact Area ◽  
The Real ◽  
Physical Mechanisms ◽  
Frustrated Total Internal Reflection ◽  
Real Contact ◽  
New Apparatus ◽  
Elastic And Plastic Deformation

Abstract The measurement of the real contact area between rough surfaces is one of the most challenging problems in contact mechanics and is of importance to understand some physical mechanisms in tribology. Based on the frustrated total internal reflection, a new apparatus is designed to measure the real contact area. For metallic samples with various surface topographies, the relation between normal load and the real contact area is measured. The unloading process is first considered to distinguish the contribution of elasticity and plasticity in contact with rough surfaces. It is found that both elasticity and plasticity are involved throughout the continuous loading process, different from some present understanding and assumptions that they play at different loading stages. A quantitative parameter is proposed to indicate the contribution of plasticity. The present work not only provides an experimental method to measure the real contact area but figures out how elastic and plastic deformation works in contact with rough surfaces.

Sign in / Sign up

Export Citation Format

Share Document