The factors that affect wear have been grouped under the following headings 6, 7. The skid resistance measurement of tyres there is a great interest in data on the tractive coefficient for a particular tyre on a particular road. To make things a little more complicated, there are actually two coefficients for every pair of materials, one for when the objects are moving and one for when theyre standing still. When two smooth surfaces are in contact, then the degree of friction between them is small because the interlocking between smooth surfaces is less. Factors affecting the friction coefficients between. Factors affecting friction coating on stainless steel 304. Which is a composite coefficient that includes all factors affecting torque and drag. From the pumping cost point of view, minimum friction is desirable as it will decrease the energy loss. We recall from an earlier handout that, for pipe flow, w f was the amount of mechanical energy dissipated to internal energy per unit mass of fluid flowing from location 1 to 2 in the below figure. Frequency and amplitude of vibration, coefficient of friction, pin on disc. Students are broken into groups of 3 simulation groups.
Dec 04, 2010 the following factors affect the amount of static friction on a surface. Considering the above problems, the factors affecting the friction during horizontal well drilling are analyzed in sichuan, and a new friction reduction tool is developed for horizontal well drilling, which reduces the torque and drag and provides supports for improving the extension capability of drill string in the long horizontal section. This value can be obtained using equation 1, which is a form of the chezy darcy expression. For objects on flat surface, the normal force is equal in magnitude to the weight. The effect of frequency and amplitude of vibration on the. If the angle was 30 degrees, then the tangent of 30 degrees is about 0. The only way to determine the accurate coefficient of friction between two materials is to conduct experiments. The results show that bitumen, temperature and coarse aggregate content of hma are factors that affect the angle. A study on experimental method and influence of some. Investigation of factors affecting the coefficient of. In physics and engineering, the coefficient of friction is denoted by the greek letter mu. Rougher surfaces have higher coefficient of frictions but to slide apart. What are the factors that affect friction and how can we. To ask what is the average friction between the tyre and the road is somewhat equivalent to inquiring as to the average friction between the pogo stick and the pavement.
Many factors affecting the friction coefficient between tires and pavement surfaces have. Coefficient of friction is different for different crosssectional shapes of a fibre and to study this experiment was carried out with the processing parameters such as. Factors affecting the tribological properties of alumina characteristics of friction and wear. Friction factor determined through roughness of the tunnels will produce a pressure drop, affecting the airflow. The proportionality coefficient is the dimensionless darcy friction factor or flow coefficient. Factors affecting friction definition, examples, diagrams. Tokyo denki received on january 20,1992 4bstract the purposes of this study are to examine systematically the effect of tribo logical factors on the coeffocient of friction and surface features. The slidinglubricated values must be used with extreme care. Friction is caused by the interactions between the sometimes microscopic roughness of different substances. Introduction since the beginning of overland transportation, man has searched for better highway. Other materials, like ptfe and ice, have low coefficients of friction with many other materials.
Surface on which the object is moved or the nature of the surface. The following factors affect the amount of static friction on a surface. Many referenced friction factors are still based on g. Friction depends partly on the smoothness of the contacting surfaces, a greater force being needed to move two surfaces past one another if they are rough than if they are smooth. Pdf evaluating the factors influencing the friction behavior of. The coefficient of friction, is found by dividing the force of friction by the normal force ff. Factors affecting friction enter your search terms. Factors affecting friction lesson teachengineering.
Several equations that we have seen have included terms to represent dissipation of energy due to the viscous nature of fluid flow. What factors affect the coefficient of friction answers. Coefficient of friction of alumina in vacuum is commonly higher than that in air. That said, some materials, like rubber, tend to have higher coefficients of friction with many other materials.
Surface friction effects in pressforming of continuous fibre. This consideration requires knowledge of the coefficient of friction between the mating surfaces of the bolt, or washer, and the composite material. Table 1 shows the mean parameters used to calculate the friction factors. Factors affecting friction factors affecting communication. Factors affecting horizontal radius friction comparative. Pa 1 where f is coefficient of friction dimensionless. Select the appropriate k value for such and select d and f for schedule 40 pipe from the table below where k is the pipe diameter in feet. Mcelroys classic paper engineering factors in the ventilation of metal mines published in 1935. Please also post any websites that may help for students aged 14 yrs old. Geometry of the exchanger equivalent length and heat e. Investigation of factors affecting the coefficient of friction and surface with a sheet drawing test 9 i 1s 8 1 33 a. The force of friction may alter depending on the following factors that affect it.
The level of friction that different materials exhibit is measured by the coefficient of friction. Jul 02, 2015 the friction is related to the temperature which affects the viscosity of the lubricant surface friction notes static coefficient of frictionstatic coefficient of frictionstatic coefficient of frictionstatic coefficient of friction the static friction coefficient between two solid surfaces is defined as the ratio of the tangential force f. The coefficient is also unique to every pair of objects. Pdf studies and research on friction, friction factor and.
Wearing pulp and paper research institute of canada, pointe claire, quebec, canada h9r3j9 synopsis electron spectroscopy for chemical analysis. The higher coefficient of friction of polypropylene yarns compared to acrylic yarns has been attributed to a smoother surface higher m, more deformable structure lower k, and a higher plasticity higher n. Friction coefficients can be calculated from actual drilling situations for a particular well geometry using a computer program with drill string surface loads as input data. Factors affecting the coefficient of friction of paper wiley online. In this study, the static and kinetic coefficients of friction between standard washers and a graphite fibrereinforced epoxy composite are found as a function of clamping force and outer ply angle. If you want your rope to behave in a predictable way, then rope coefficient of friction. Block a is kept on top of block b, the coefficient of static friction between a and b is 0. Friction is the name given to the force that opposes the motion of one body sliding over another. On the nature of the two surfaces that are in contact. So rubber would have a different coefficient of friction on pavement, than on glass. A friction meter for determining the coefficient of kinetic.
For example, in the energy balance, the dissipation function. If there need to be 4 students in a simulation group, two students should join expert group 2. Oct 30, 2003 in an ideal world, fricitonal forces are due to 2 things, the coefficient of friction, mu and the normal force. One source suggests that in a friction measurement there are often three bodies involved, the measuring tyre, the road surface and some kind of contaminant interacting with both tyre and road like for example water wet friction, dust or wear particles etc.
What factors affect the static friction of a wooden block. The type of surface on which the object is sitting affects the coefficient of friction. In this study, the miu average value of the friction coefficient, which is correlated with the slipperiness or nonslipperiness of fabrics, and mmd fluctuations of the average frictional coefficient, which is correlated with the smoothness or roughness, were measured for more than 50 versatile fabrics by using the friction tester, kesse. Friction factors determination and comparison in potash mines. However, friction decreases with smoothness only to a degree. Effect of load and sliding speed on wear and friction of. Factors affecting the friction coefficients between metallic washers. It reduces the coefficient of friction at the chip tool interface and increases tool life. Factors that influence the adhesion coefficient between. Friction coefficient definition the coefficient of friction determines how much of the normal force is transformed into drag or torque and it is an important factor in calculating torque and drag in a wellbore. The most significant factors affecting the rope cof are the surface finish.
Dec 17, 2012 factors affecting friction one source suggests that in a friction measurement there are often three bodies involved, the measuring tyre, the road surface and some kind of contaminant interacting with both tyre and road like for example water wet friction, dust or wear particles etc. This dimensionless coefficient will be a combination of geometric factors such as. International journal of scientific and research publications, volume 3, issue 3, march 20 1 issn 22503153. Following are the two factors on which friction depends.
Friction depends partly on the smoothness of the contacting surfaces, a greater force being needed to move two surfaces past one another if they are rough than. Factors affecting the friction coefficients between metallic. Determining the coefficient of friction succeed in physical science ramp until the book started to slide and then measured the angle of the ramp, you could determine the coefficient of friction between the book and the ramp. Factors affecting the coefficient of kinetic friction. The factors affecting overall heat transfer coefficient are. Furthermore, the drag coefficients for rotational movement, for axial movement or for a combination of the two, will often be different, and may also vary with the direction of movement. Friction coefficient an overview sciencedirect topics. Factors affecting fluid friction definition frictional force on an object in a fluid depends on its speed with respect to fluid and on the shape of the object and nature of the fluid.
Within each group, students decide which area of expertise to join, either mass, friction, or velocity expert groups. As a result, it was found that the friction coefficient was mainly determined by the linearity of weave texture, the fuzziness of the fabric and the real contact area between fabrics and rubbed materials. Factors affecting fabric slipperiness keiko suganuma. Factors affecting the coefficient of friction of paper. What are the factors affecting overall heat transfer co. Physical and chemical properties of work material influence tool life by affecting form stability and rate of wear of tool. Below are provided a small number of values showing approximate values of friction coefficients to be used for steel screw fastened connections.
Measurements of airway friction factors were obtained during ventilation surveys of thirteen metal mines around the world. There are many factors at work in the grip of a tyre, not just friction. Factors affecting the coefficient of friction of paper factors affecting the coefficient of friction of paper gurnagul, n ouchi, m. As a result, friction is primarily affected by the roughness of an object. The coefficient of friction was related to the surface free energy of the plastic, to the surface tension of lubricating liquids and to interactions between the polar groups of boundary lubricants and chemical groups on the polyethylene surface. The tribocharging of the contacting surfaces, generated during sliding friction, was determined to be a major influence on the dynamic coefficient. Wider tyres are made of softer compounds of rubber, which have a better coefficient friction. Physiochemical properties of fluids both cold and hot such a viscosity, density, specific heat, thermal conductivity. The mu depends on the materials of the two surfaces that are in contact. The coefficient of friction is required in calculating tightening torques and resulting bolt tensile forces and stress and in calculating the resulting friction between the connected surfaces. Factors that influence the adhesion coefficient between wheel and rail hua chen senior researcher, track dynamics, railway dynamics division fig. A table below shows approximate friction coefficients for various materials. Pdf electron spectroscopy for chemical analysis esca studies on a variety of paper samples show that for samples of similar surface.
Most mechanized mines now incorporate airways that are larger, have more advanced support systems, and more uniform openings. The magnitude of the force of static friction between any two surfaces in contact has a value of, where is the coefficient of static friction and n is the normal force. What factors determine the coefficient of friction. The values displayed in table 2 correspond to the mean friction factors per season and the general. Factors that influence the adhesion coefficient between wheel. The friction and friction factors are very significant factors in flow through pipes, channels, heat exchangers. Friction losses in pipe fittings resistance coefficient k. Determine l friction loss in pipe fittings in terms of equivalent length in feet of straight pipe. The slope of the line corresponds to the coefficient of friction for the two particular surfaces involved. Also coefficient of kinetic friction between a and b is 0. Pdf factors affecting the coefficient of friction of paper.
What factors affect the static friction of a wooden block on. The most significant factors affecting the rope cof are the surface finish of the substrate, material type not shown, the fiber coating type, and the amount of. In an ideal world, fricitonal forces are due to 2 things, the coefficient of friction, mu and the normal force. Pdf studies and research on friction, friction factor. Understanding the nut factor in threadedfastener torque.
Friction definition, types of friction, applications. The friction coefficient of textile materials should be presented with accurate material descriptions and experimental conditions since it varies with many operational factors and friction measuring instruments, as well as with fibre, yarn and fabricrelated factors. The higher the value of, the stronger is the frictional force that resists the motion if two objects are going to slide past each other. Friction is also affected by the mass or weight of the object as well. Many factors affecting the friction coefficient between tires and pavement surfaces have been found through laboratory and field investigations. Determination of the friction factors in potash mines.
Electron spectroscopy for chemical analysis esca studies on a variety of paper samples show that for samples of similar surface roughness the coefficient of. All values are approximate and are only suitable for guidance only. These companies can provide surface coating fluids containing particles to increase the coefficient of friction i. Electron spectroscopy for chemical analysis esca studies on a variety of paper samples show that for samples of similar surface roughness the coefficient of friction is a function of the amount of extractives that are present on the sheet surface. And what is the exact relationship between the angle of inclination and the coefficient of static friction. Factors affecting fabric slipperiness show all authors.
One device still in the development stage showed promise of measuring friction coefficient under simulated conditions of landing aircraft. When pressforming composites, the main factors affecting friction are. W f is often used to define a head loss h l, w f gh l 3 figure 1. For example, applying the motosh equation to an m121. The two materials and the nature of their surfaces. The majority of these mines employed traditional jumbo drill and blast development techniques to drive the main airways for which these friction factors are representative. Hence birds and fishes have special shapes so that they can easily overcome fluid friction.
Nov 08, 2010 the coefficient is also unique to every pair of objects. In most cases, the velocity of the sliding object does not affect the coefficient of friction. They have been either measured in situ or calculated with the data collected from 2008 to 20. Coefficient of sliding friction by ron kurtus physics. Since the chezydarcy coefficient of friction is dimensionless, the atkinson friction factor has the units. The coefficient of friction of the compound is only mildly affected by the filler while wear factor is a strong function of the filler. Factors affecting friction coefficient 21 skidresistance standard 61 methods of improving friction coefficient 61 summary 64 recommended fieldtesting device 67 references 68 distribution list 72 library catalog card 75. Analysis of factors affecting drilling friction and. At this point you should conclude that no macroscopic properties of the object affect the coefficient of friction. In the first instance, it may not be that you are comparing like with like.
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