Belt-Drive Mechanics: Friction in the Absence of Sliding

2019 ◽  
Vol 86 (10) ◽  
Author(s):  
Yingdan Wu ◽  
Michael J. Leamy ◽  
Michael Varenberg
Keyword(s):  
Energy Dissipation ◽  
Stress Analysis ◽  
Shear Strain ◽  
Contact Area ◽  
Significant Contribution ◽  
Power Transmission ◽  
Rolling Friction ◽  
Belt Drive ◽  
Unsteady Operation ◽  
Spatio Temporal

Recent studies have shown that steady and unsteady operation of a belt drive may exhibit regimes absent of sliding at the belt–pulley interface, where instead detachment waves serve to relax stress in the so-called “slip” arc. To explore this finding further, herein we present an experimental and theoretical investigation into frictional mechanics in a simple belt drive system. To estimate friction experimentally, we perform a stress analysis based on spatio-temporal measurements of the belt tension, traction, and contact area evolution. Subsequently, we develop a model taking into account both bulk and surface hysteretic losses to explain the experimental observations. Our results show that the shear strain at the belt–pulley interface differs significantly between the driver and the driven pulleys, resulting in much larger mechanical losses in the driver case. The shear strain drops at the transition from the adhesion to the slip arc, and, in contrast to accepted theories, the slip arc contributes little to nothing to the power transmission. Our model reveals that the contact area evolution correlates to the shear traction changes and that viscoelastic shear and stretching dominate in the belt rolling friction. A significant contribution of detachment waves to the energy dissipation explains the higher mechanical losses observed in the driver case.

scholarly journals The power transmission stability and efficiency of V-belts

2016 ◽  
Vol 12 (1) ◽  
pp. 25-49
Author(s):  
László Kátai ◽  
Péter Szendrő ◽  
Péter Gárdonyi
Keyword(s):  
Internal Friction ◽  
Food Industry ◽  
Power Transmission ◽  
Angular Displacement ◽  
Hysteresis Loss ◽  
Damping Factor ◽  
Belt Drive ◽  
Agricultural Machinery ◽  
Plate Structure ◽  
Belt Drives

The V-belt drive is a rather popular, widely used form of power transmission in agricultural and food industry engineering. At the same time, its stability, the lifetime of V-belt is influenced by several environmental factors, namely in the food industry by the contamination affecting the belt sides, the ambient temperature, humidity and the occasionally aggressive (acidic, alkaline air, air saturated with gases, etc.) medium. In the case of agricultural machinery, the vibration caused by uncertainly oriented pulleys with bearing in different plate structures (often being shaken in the fields) as well as alignment adjustment inaccuracies jeopardize the reliability of the parameters of the drive. Furthermore, the efficiency is determined by several factors together: the slippage occurring during drive transmission, the hysteresis loss resulting from the external and internal friction occurring with the belt entering and exiting the pulley. Experimental equipment and calculation methods were developed to determine the dynamics of temperature increase generated by the belt and pulley relationship. The temperature generated in the V-belt was measured as a function of pretension, pulley diameter and bending frequency. The so-called damping factor characterizing the contact with the pulley (the external friction when entering and exiting the groove) and the hysteresis loss (inner friction) are also determined. On the basis of the damping factor (ζ ≈ 400 Ns/m2) of the V-belt involved in the experiments the other losses (Poth) occurring from the pulley—V-belt contact and internal friction may be estimated. The drive parameters may be optimized with the mathematical model describing the effect of the pulley diameter and belt frequency on the increase in temperature. A standardized calculation method as well as design factors valid for the properly adjusted drive and normal operating conditions determined through empirical and laboratory experiments are used for the sizing of V-belt drives. The lifetime of V-belt drives designed in this way, used in extreme conditions typical of agricultural machinery will not be appropriate and will not provide clear, predictable information for maintenance planning. In such cases the results of our own many lifetime tests conducted in the given circumstances can be safely relied on. The agricultural harvesting machines are large plate-body self-propelled structures on which most of the power supply of the (threshing, cleaning, moving, etc.) machine units handling the crop is realized via belt drives. The distance and angular displacement of the axes involved in the drive can vary within wide limits. The misalignment and angular displacement of the pulleys can be the result of installation instability — due to the plate structure — and the deformation of the plate structure occurring during the operation as well. V-belt drives operate satisfactorily under such conditions as well, however these faults are unfavourable in terms of belt lifetime and result in the reduction of drive efficiency. A further aim of our research is to examine through experiments the lifetime and efficiency of V-belts used in agricultural machines as a function of drive adjustment errors. According to the results of the measurements of the geometrical adjustment errors of V-belt drives performed in the field, the pulleys of agricultural equipment are not always positioned in the medium plane of the drive. In our experiments these data served as independent variables. Figure 1 shows the arrangement of a V-belt drive in a grain harvester with the laser pulley alignment measuring instrument installed as an accessory. In the case of many machine types in 80% of the tested drives three times the permissible error was measured, and because of off-road use, due to dynamic load these errors further increased as a result of the frame deformation. The results of both the belt bending testing and the geometrical adjustment testing of the drive offer great help in the design of belt drives. At the same time they can be the source of lifetime and efficiency forecasts.

Viscoelastic Tooth Root Stress Analysis on Fiber Reinforced Thermoplastic Poly-Imide (TPI) Gears

2000 ◽  
Author(s):  
Gong Donghui ◽  
Ichiro Moriwaki ◽  
Kenji Saito
Keyword(s):  
Carbon Fiber ◽  
Stress Analysis ◽  
Power Transmission ◽  
Hysteresis Loss ◽  
Tooth Root ◽  
Fiber Reinforced ◽  
Standard Specimens ◽  
Sufficient Strength ◽  
Root Stress ◽  
Poly Imide

Abstract Although thermoplastic poly-imide (TPI) gears do not have sufficient strength for power transmission, carbon fiber reinforcement greatly improves the strength of TPI gears. Previous experimental research showed that although standard specimens made from carbon fiber reinforced (CFR) TPI has 2.4 times strength in static bending than specimens made from natural TPI, gears made from CFR-TPI yields bending fatigue strength about 10 times greater than gears made from natural TPI. The present paper explains this phenomenon using viscoelastic tooth root stress analysis. The experiments indicated that the natural TPI gears showed much larger viscoelasticity than the CFR-TPI gears. Thus, tooth root stresses were calculated for cases of large and small viscosity moduli. These calculations showed tooth root stress increased with the increase in the viscosity modulus. Also, viscoelasticity may induce heat due to hysteresis loss, and this heat should reduce gear durability. The increase in tooth root stress and the heat due to hysteresis loss must make the durability of the natural TPI gears very small. Therefore, the CFR-TPI can yield much more durable gears than the natural TPI.

Belt-Drive Mechanics: Energy Losses in the Presence of Detachment Waves

2019 ◽  
Author(s):  
Yingdan Wu ◽  
Michael J. Leamy ◽  
Michael Varenberg
Keyword(s):  
Rolling Friction ◽  
Drive System ◽  
Energy Losses ◽  
Belt Drive ◽  
Interface Shear ◽  
Shear Traction ◽  
Friction Moment ◽  
The Difference ◽  
Contact Arc ◽  
Good Agreement

Abstract The dissipative rolling friction moment in a simple belt-drive system is estimated both experimentally and computationally while taking into account the detachment events at the belt-pulley interface. Shear traction is estimated based on measurements of the shear strain along the contact arc. It is shown that the dissipative moment can be approximated by taking the difference between the shear traction and the load carried by the belt. A model is developed for analyzing the contributions of different components to this dissipative moment by considering both the volumetric and surface hysteresis losses. The computed rolling friction moment is found to be in good agreement with that estimated based on the experiments. It is also found that while the shear- and stretching-induced energy losses contribute the most to the dissipation in the belt drive system, the losses associated with the Schallamach waves of detachment make up a considerable portion of the dissipation in the driver case.

Adhesion and Friction on the Nanometer Scale: Energy Dissipation During Sliding of Antimony Islands on Graphite and MoS2

2005 ◽  
Author(s):  
Udo D. Schwarz ◽  
Claudia Ritter ◽  
Markus Heyde ◽  
Klaus Rademann
Keyword(s):  
Energy Dissipation ◽  
Contact Area ◽  
Power Dissipation ◽  
Pyrolytic Graphite ◽  
Threshold Value ◽  
Nanometer Scale ◽  
Dynamic Force ◽  
Low Dissipation ◽  
Frictional Forces ◽  
Direct Proportionality

Antimony nanoparticles grown on highly oriented pyrolytic graphite and molybdenum disulfide were used as a model system to investigate the contact area dependence of frictional forces. Controlled translation of the antimony nanoparticles was induced by the action of the oscillating tip in a dynamic force microscope. During manipulation, the power dissipated due to tip-sample interactions was recorded. We found that the threshold value of the power dissipation needed for translation depends linearly on the contact area between the antimony particles and the substrate. Assuming a linear relationship between dissipated power and frictional forces implies a direct proportionality between friction and contact area. Particles smaller than 10000 nm2, however, were found to show dissipation close to zero. To explain the observed behavior, we suggest that structural lubricity might be the reason for the low dissipation in the small particles, while elastic multistabilities might dominate energy dissipation in the larger particles.

Junction Growth and Energy Dissipation at the Very Early Stage of Elastic-Plastic Spherical Contact Fretting

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
A. Ovcharenko ◽  
I. Etsion
Keyword(s):  
Energy Dissipation ◽  
Friction Force ◽  
Contact Area ◽  
Early Stage ◽  
Static Friction ◽  
Relative Displacement ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Direct Measurements ◽  
Elastic Perfectly Plastic

The contact area, friction force, and relative displacement evolution at the very early stage of fretting are investigated experimentally. Copper and steel spheres of various diameters are loaded against a hard sapphire flat by a range of normal loads deep into the elastic-plastic regime of deformation. A reciprocating tangential loading is then applied with a maximum loading below the static friction to avoid gross slip. Real-time and in situ direct measurements of the contact area, along with accurate measurements of the friction force and relative displacement, reveal substantial junction growth and energy dissipation mainly in the first loading cycle. The so-called “slip amplitude” is found to be attributed to residual tangential plastic deformation rather than to interfacial slip. Elastic shake-down is observed for the 2.5% hardening steel spheres while plastic shake-down is observed in the case of the elastic perfectly-plastic copper spheres.

Full Sliding Adhesive-Like Contact of V-Belts

2002 ◽  
Vol 124 (4) ◽  
pp. 706-712 ◽  
Author(s):  
Go¨ran Gerbert ◽  
Francesco Sorge
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Power Transmission ◽  
A Priori ◽  
Belt Drive ◽  
Natural Boundary ◽  
Condition Problem ◽  
New Type ◽  
Wrap Angle ◽  
Natural Boundary Conditions

Analysis of power transmission in a belt drive consisting of, e.g., two pulleys might be treated as a boundary value problem. Tight side tension FT, slack side tension FS and the wrap angle α are the three natural boundary conditions. In the literature, theories are developed where seating and unseating as well as the power transmitting part of the contact are considered. The solutions presented so far don’t fulfill the boundary conditions properly, since a certain tension ratio FT/FS is associated with a certain contact angle and not an a priori specified one. It appears that a new type of full sliding solution must be introduced to handle the boundary condition problem. During part of the contact there is almost no tension variation in spite of the full sliding conditions. The designation adhesive-like solution is here introduced for that part. Conditions and character of the adhesive-like solution are outlined in the paper.

scholarly journals Energy dissipation and liquefaction at Port Island, Kobe

1998 ◽  
Vol 31 (1) ◽  
pp. 33-50 ◽  
Author(s):  
R. O. Davis ◽  
J. B. Berrill
Keyword(s):  
Shear Stress ◽  
Energy Dissipation ◽  
Shear Strain ◽  
Pore Pressure ◽  
Calculation Method ◽  
Horizontal Plane ◽  
Dissipated Energy ◽  
Stress And Strain ◽  
Shear Stress And Strain ◽  
Reclaimed Soils

The Port Island, Kobe downhole records from the Hyogo-ken Nanbu earthquake are analysed to obtain approximate histories of shear stress, shear strain and dissipated energy at a range of depths. Our calculation method relies on measured accelerations in the horizontal plane to produce horizontal components of shear stress and strain using instantaneous modal superposition. A simple dissipated energy-dynamic pore pressure relationship is used to model the development of pore pressure leading to liquefaction. The results show a rapidly developing zone of liquefaction which initiates at a depth of roughly 15 metres in the Port Island reclaimed soils.

scholarly journals Geographic and Opportunistic Recovery with Depth and Power Transmission Adjustment for Energy-Efficiency and Void Hole Alleviation in UWSNs

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 709 ◽  
Author(s):  
Abdul Mateen ◽  
Muhammad Awais ◽  
Nadeem Javaid ◽  
Farruh Ishmanov ◽  
Muhammad Afzal ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Routing Protocols ◽  
Power Transmission ◽  
State Of The Art ◽  
Maximum Energy ◽  
Underwater Wireless Sensor Networks ◽  
Routing Schemes ◽  
End To End Delay ◽  
Extra Energy ◽  
Wide Range

Underwater Wireless Sensor Networks (UWSNs) are promising and emerging frameworks having a wide range of applications. The underwater sensor deployment is beneficial; however, some factors limit the performance of the network, i.e., less reliability, high end-to-end delay and maximum energy dissipation. The provisioning of the aforementioned factors has become a challenging task for the research community. In UWSNs, battery consumption is inevitable and has a direct impact on the performance of the network. Most of the time energy dissipates due to the creation of void holes and imbalanced network deployment. In this work, two routing protocols are proposed to avoid the void hole and extra energy dissipation problems which, due to which lifespan of the network increases. To show the efficacy of the proposed routing schemes, they are compared with the state of the art protocols. Simulation results show that the proposed schemes outperform the counterparts.

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