Variation in the Apparent Coefficient of Friction of Wheat on Galvanized Steel

1988 ◽  
Vol 31 (5) ◽  
pp. 1518-1524 ◽  
Author(s):  
S. A. Thompson ◽  
R. A. Bucklin ◽  
C. D. Batich ◽  
I. J. Ross
2008 ◽  
Vol 52 (No. 2) ◽  
pp. 50-56 ◽  
Author(s):  
R. Polat ◽  
S. Tarhan ◽  
M. Çetin ◽  
U. Atay

Technical information and data on the physical and mechanical properties of agricultural and animal products are necessary to design various equipments for agriculture and industry. In this study some physical properties such as mass, length, diameter, geometric mean diameter, surface area, sphericity, volume, coefficient of friction and packaging coefficient were determined for Japanese quail eggs. Furthermore, the mechanical behaviour of Japanese quail eggs was determined in terms of average rupture force, deformation and toughness (energy absorbed by the Japanese quail eggs per unit volume). Egg samples were compressed along their <i>X</i> and <i>Z</i>-axes. The average values of their mass, length, width, shell thickness, geometric mean diameter, surface area, sphericity, volume and packaging coefficient were measured to be 12.69 g, 34.87 mm, 26.20 mm, 0.27 mm, 28.82 mm, 2 608.5 mm<sup>2</sup>, 1.10, 359.17 mm<sup>3</sup>, 0.469, respectively. The values of the coefficient of friction for quail eggs on the surfaces of plywood, glass, galvanized steel and fibreglass were 0.301, 0.282, 0.274 and 0.266, respectively. The highest rupture force, deformation and toughness were obtained when Japanese quail eggs were loaded along their X-axis. Compression along the <i>Z</i>-axis required the least compressive force to break the eggs as compared to the other compression axes. Rupture force, deformation, absorbed energy and toughness for the <i>X</i>-front axis were determined to be 10.51 N, 1.5 mm, 7.88 Nmm and 0.219 Mj/mm<sup>2</sup>, respectively.


2017 ◽  
Vol 23 (3) ◽  
pp. 175-181 ◽  
Author(s):  
Charles V. Schwab

Abstract. Calculation of the extraction force for a grain entrapment victim requires a coefficient of friction between the grain and the surface of the victim. Because denim is a common fabric for the work clothes that cover entrapment victims, the coefficient of friction between grain and denim becomes necessary. The purpose of this research was to calculate the apparent coefficient of friction of wheat on denim fabric using a proven procedure. The expectation is to improve the current understanding of conditions that influence extraction forces for victims buried in wheat. The apparent coefficient of friction of wheat on denim fabric was calculated to be 0.167 with a standard deviation of ±0.013. The wheat had a moisture content of 10.7% (w.b.) and bulk density of 778.5 kg m-3. The apparent coefficient of friction of wheat on denim was not significantly affected by pull speeds of 0.004, 0.008, and 0.021 mm s-1 nor normal grain pressures of 3.2, 4.8, 6.3, 7.9, and 11.1 kPa. This is a beginning of understanding the conditions that influence the extraction forces for grain entrapment victims. Keywords: Farm safety, Grain entrapment, Grain rescue, Grain extraction.


2008 ◽  
Vol 53 (No. 1) ◽  
pp. 14-19 ◽  
Author(s):  
R. Rusinek ◽  
M. Molenda

he present paper examines the static and kinetic coefficient of friction of rapeseed. The project utilized two methods of determination of coefficient of friction of rapeseed: according Eurocode 1 (kinetic) in direct shear test and (static) in model silo. Samples of rapeseed in a range of moisture content from 6 to 15% w.b. were used and the tests were performed for galvanized steel, stainless steel and concrete B 30. Coefficient of friction for both steel types approached stable value for all levels of moisture content w.b. in a range from 0.11 to 0.18, for concrete B 30 it was found in a range from 0.25 to 0.43. The coefficient of static friction found in model silo decreased with an increase in vertical pressure from 0.3 to 0.2 for first loading, while in subsequent loading cycles decreased from 0.2 to 0.1.


1991 ◽  
Vol 64 (1) ◽  
pp. 108-117 ◽  
Author(s):  
C. W. Extrand ◽  
A. N. Gent ◽  
S. Y. Kaang

Abstract The contact width, and hence contact area, for an elastic wedge pressed against a rigid flat surface appears to be proportional to the applied load per unit length. For a particular rubber sample, the reciprocal of the constant of proportionality, i.e., the mean normal pressure, was 130 kPa, i.e., about 7% of the tensile modulus E of the material. It was also independent of sliding speed over the range examined. Thus, a sharp wedge gave a relatively high loading pressure, independent of the applied load. As a result, the coefficient of friction was also independent of applied load over a wide range. The coefficient of friction was measured for a wedge of an unfilled natural rubber vulcanizate over wide ranges of sliding speed (50 µm/s to 100 mm/s) and test temperature (3°C to 63°C). It was found to increase with sliding speed and decrease with temperature over these ranges. The results at different temperatures were superposable using the WLF rate-temperature equivalence to create a master curve of friction vs. reduced sliding speed, rising from a value of about 1.5 at high temperatures and low speeds to about 5 at low temperatures and high speeds. Chlorination of a thin surface region reduced the coefficient of friction and its dependence on speed and temperature. It then became similar to that typically found for thermoplastics, 0.4 to 0.7. The geometry of sliding a flexible strip against a rigid curved surface caused high values of the apparent coefficient of friction to be obtained at relatively small departures from normal loading. In an extreme case, frictional seizure was observed when a high-friction sample contacted the glass surface at an angle of about 15° to the direction of loading. The apparent coefficient of friction then became indefinitely large. This same phenomenon of abnormally large frictional effects would be expected to occur in the case of conventional windshield-wiper blades, sliding over curved glass windshields.


Author(s):  
Mansoureh Pourjafar

<p>Some physical properties of Iranian Jujube fruit were evaluated. Jujube fruit samples mean values of length, width, thickness were found as 18.005mm, 14.96 mm, 15.26 mm. Arithmetic mean diameter, geometric mean diameter were found as 16.08mm, 16.01 respectively and surface area, Sphericity, porosity, mass, volume, bulk density and true density were also found as: 805.65 mm<sup>2</sup> ,89%, 77.2%, 1.45gr, 2.61 cm<sup>3</sup> , 0.23gr cm<sup>-3</sup>, 0.55gr cm<sup>-3</sup> respectively. Projected area perpendicular to length, width and thickness were measured as, 152.03 mm<sup>2</sup>, 220.02 mm<sup>2</sup>, 271.4mm<sup>2</sup> respectively. With comparison between friction coefficients on different surface for Jujube fruit. The results showed that the static coefficient of friction was more than dynamic coefficient of friction.The tests done on the galvanized steel surface, plywood and glass surface. The most coefficient of friction was found on the plywood surface and the least coefficient of friction was measured on the glass surface.</p>


2019 ◽  
Vol 20 (6) ◽  
pp. 624 ◽  
Author(s):  
Sana Werda ◽  
Arnaud Duchosal ◽  
Guénhaël Le Quilliec ◽  
Antoine Morandeau ◽  
René Leroy

The main aim of this paper was to reproduce the frictional behaviour that occurred in milling with a pin-on-cylinder system. Three different tribological tests were conducted reproducing friction phenomenon that happened in three machining conditions: (i) dry rubbing, representing the dry machining condition, (ii) MQL applied to front face rubbing which was similar to milling with MQL applied on the insert rake face and (iii) MQL applied to rear end rubbing which was similar to milling with MQL applied on flank face. Tribological tests were carried out with coated tungsten carbide pins rubbing on X100CrMoV5 steel cylinder. Apparent coefficient of friction, adhesion area and heat flux transmitted to the pin were analysed. It has been shown that MQL rear end rubbing provided a lower adhesion area and lower apparent coefficient of friction than with MQL front face rubbing. Furthermore, MQL rear end rubbing resulted in a greater cooling ability. These findings helped to explain why better results were obtained with MQL flank face lubrication in milling compared to MQL rake face lubrication.


1989 ◽  
Vol 32 (5) ◽  
pp. 1769-1773 ◽  
Author(s):  
R. A. Bucklin ◽  
S. A. Thompson ◽  
I. J. Ross ◽  
R. H. Biggs

1993 ◽  
Vol 36 (6) ◽  
pp. 1915-1918 ◽  
Author(s):  
R. A. Bucklin ◽  
S. A. Thompson ◽  
I. J. Ross ◽  
R. H. Biggs

Author(s):  
Abhishek Kumar ◽  
Basil Kuriachen ◽  
Surender Ontela

Inconel 718 is gaining its importance in the aerospace and power plant industries because of its high strength to weight ratio. The lack of understanding of the tool chip interface for Inconel 718 restricts the prediction of the apparent coefficient of friction and thus the cutting forces, thereby the machining efficiency. In the present study an analytical model has been developed accounting the actual variation of stresses over the rake face. The model focuses on the variation of shear stresses in the sticking region and has been considered to be increasing exponentially with distance from tool tip. The primary shear zone is assumed to be a thin layer with constant thickness and has been modelled using Johnson Cook material model. The shear stresses at the entry and exit of the primary shear zone has been calculated using iterative techniques proposed in the literature. The secondary shear zone has been analyzed dividing the contact length into two distinct regions and each region has been dealt separately. The ratio of real area of contact to the apparent area of contact has been given consideration and dealt with at macroscopic level. Experimental values have been extracted from previous studies on Inconel 718. The predictions of the analytical model was found to be in good agreement with experimental results. The experimental apparent coefficient of friction was obtained as 0.5119 against 0.4733 from the developed model at a velocity of 70 mm/min, depth of cut of 1mm, nose radius of 0.8mm and with negative rake angle (−6°) with CNMG0812 tool. The predicted and the experimental friction coefficient showed a variation of 7.07% – 10% and thus can serve as reliable model for Inconel 718.


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