We derive the equations of motion for an extensible belt on a pulley in which all effects of inertia, including (for the first time) acceleration due to stretching, are retained in the momentum balance. The equations of motion are integrated using a time-accurate explicit solution procedure. The pulleys are modeled as cylindrical rigid bodies.
Friction between the belt and the pulleys is modeled using an asperity-based Coulomb friction model. Belt reinforcements are modeled using one-dimensional truss elements at the top surface of the belt. The belt rubber matrix is modeled using three-dimensional brick elements. In this paper, the effect of the belt thickness on the aforementioned response quantities is studied using a two-pulley belt-drive. However, flat rubber belts have a finite thickness and the reinforcements are typically located near the top surface of the belt. In previous papers, those quantities were predicted using thin shell, beam, or truss elements along with a Coulomb friction model.
Compared to flat belt drives or models that neglect radial friction, significant differences in the steady belt-pulley mechanics arise in terms of belt radial penetration, free span contact points, tension, friction, and speed variations.Ī necessary condition for high-fidelity dynamic simulation of belt-drives is to accurately predict the belt stresses, pulley angular velocities, belt slip, and belt-drive energy efficiency. The governing boundary value problem (BVP) with undetermined boundaries is converted to a fixed boundary form solvable by a general-purpose BVP solver. This allows system analysis, such as speed/ torque loss and maximum tension ratio. A new computational technique is developed to find the steady mechanics of a V-belt drive.
Different from single-pulley analy-ses, the entry and exit points between the belt spans and pulleys must be determined in the analysis due to the belt radial penetration into the pulley grooves and the coupling of the driver and driven pulley solutions. The pulley grooves generate two-dimensional radial and tangential friction forces whose undetermined direction depends on the relative speed between belt and pulley along the contact arc. The belt is modeled as an axially moving string with the tangential and normal accelerations incorporated. The steady mechanics of a two-pulley belt drive system are examined where the pulley grooves, belt extension and wedging in the grooves, and the associated friction are considered. The solution concepts for specific components were evaluated using morphological analysis. Lastly, auxiliary instrumentation had to be accommodated by the test stand and its data acquisition system. Second, the test stand had to be flexible regarding the emulation of possible drive configurations. First, a variety and range of reproducible adjustable parameters were required. The design of the test stand was governed by modularity regarding multiple aspects. Therefore, in this work an innovative test stand was designed and build, with a maximum belt tension of 1500 N and a maximum belt speed of 50 m/s, enabling the transfer of 75 kW. Experimental investigation is key in achieving both goals.Įxisting test stands are not able to replicate high performance applications and accelerating the lifetime assessment of flat belts due to limited capabilities in belt force and speed.
This requires a deeper understanding on the fundamental transmission mechanics of flat belts as well as the failure mechanism limiting their lifetime. Hence, there is a demand to increase the service lifetime of power transmission flat belts to decrease cost and downtime due to belt failure. Since they transfer power based on friction, they are subject to wear and consequently are expendable parts. Additionally, the simple, low maintenance and cost effective setup as well as high energy efficiency up to 98 % make them an attractive choice. Compared to chain or gear drives, belt drives express advantages such as low-noise, and shock- and vibration-damping characteristics. Flat belts are machine elements used for the power transmission between rotating elements.