Hysteretic behavior of a belt tensioner: modeling and experimental investigation

In this paper we describe the modeling of the hysteretic behavior of belt tensioners. An initial experimental device is composed only of the tensioner by using forcing frequencies, preloads and deflection amplitudes. It permits the identification of the parameters of the restoring force model used. Comparison of the measured and predicted force deflection loops of the tensioner subjected to large deflections permits preliminary validation of the model.The second experimental device consists of a belt-tensioner system. Its non-linear modeling includes the above hysteretic model and the belt’s longitudinal characteristics. Validation of the belt-tensioner model is completed by comparing the measured and predicted belt tension. Finally, it is shown by using a parametric investigation and phase-plane portrait that the response of the belt-tensioner system increases with the frequency and the amplitude of the excitation

An analysis of the modified Dahl and Masing models: application to a belt tensioner

The objective of this paper is to describe the modified Dahl and Masing models used for predicting hysteretic behavior, and tested on a belt tensioner for automotive engines. An experimental study with deflection imposed on the tensioner is first carried out to identify hysteresis loop parameters for the two models. The models are implemented in the general motion equations which govern the behavior of a belt–tensioner–mass system. Particular attention is paid to the use of numerical schemes. The numerical and experimental investigations show the reliability of the modified Dahl model

Experimental investigation on the dynamic characteristics and transverse vibration instabilities of transmission belts

Serpentine belt drives are often used in front end accessory drive of automotive engine. Dynamic characteristics of belts play an important role in the behavior of such transmission and are inputs of simulation software. Moreover, free belt spans exhibit transverse vibration non linear instabilities. An experimental investigation is conducted on multi-ribbed belts, first for the determination of longitudinal stiffness and damping, bending rigidity, then to highlight the belt span transverse instabilities. An experimental set-up has been designed, it enables ,the observation and analysis of instabilities of belt spans axially excited, the determination of instability chart

From transmission error measurement to Pulley-Belt slip determination in serpentine belt drives: influence of tensioner and belt characteristics

Serpentine belt drives are often used in front end accessory drive of automotive engine. The accessories resistant torques are getting higher within new technological innovations as stater-alternator, and belt transmissions are always asked for higher capacity. Two kind of tensioners are used to maintain minimum tension that insure power transmission and minimize slip: dry friction or hydraulic tensioners. An experimental device and a specific transmission error measurement method have been used to evaluate the performances of a generic transmission by determining the pulley-belt slip for these two kinds of tensioner. A data acquisition technique using optical encoders and based on the angular sampling method is used with success for the first time on a non synchronous belt transmission. Transmission error between pulleys, pulley/belt slip are deduced from pulley rotation angle measurements.Results obtained show that: the use of tensioner limits belt slip on pulleys, pulley-belt slip is reachable from transmission error measurement, belt non uniform characteristics are responsible of low frequency modulations of transmission error

Rheological and restoring force models regarding belt tensioner dymamic behavior: prediction and experiment

The objective of this paper is to compare the Masing and modified Dahl model efficiency regarding the prediction of the hysteretic behavior of a belt tensioner used for automotive engines. A first experimental study with deflection imposed on the tensioner is carried out to identify hysteresis loop parameters for the two models. The models are then implemented in the general motion equations modeling the behavior of a belt - tensioner - mass system. The comparison beteen numerical and experimental results show that these two models perform satisfactorily and that the modified Dahl model is a little more efficient

From transmission error measurement to Pulley-Belt slip determination in serpentine belt drives : influence of tensioner and belt characteristics

Serpentine belt drives are often used in front end accessory drive of automotive engine. The accessories resistant torques are getting higher within new technological innovations as stater-alternator, and belt transmissions are always asked for higher capacity. Two kind of tensioners are used to maintain minimum tension that insure power transmission and minimize slip : dry friction or hydraulic tensioners. An experimental device and a specific transmission error measurement method have been used to evaluate the performances of a generic transmission by determining the pulley–belt slip for these two kinds of tensioner. Transmission error between pulleys, pulley/belt slip are deduced from pulley rotation angle measurements. Results obtained show that : the use of tensioner limits belt slip on pulleys, pulley–belt slip is reachable from transmission error measurement, belt non uniform characteristics are responsible of low frequency modulations of transmission error

Rôle des tendeurs sur le comportement dynamique d’une transmission par courroie

Les transmissions par courroie poly-v (striées), utilisées notamment pour l’entraînement des accessoires d’un moteur automobile, sont généralement équipées d’un galet tendeur afin de réduire les vibrations et de garantir une tension minimum suffisante. Deux types de tendeurs peuvent être utilisés, ils diffèrent par la façon dont est généré l’amortissement : le premier, dit ‘mécanique’ utilise le frottement sec ; le second, dit ‘hydraulique’ est équipé d’un amortisseur. Les deux sont équipés de ressorts de rappel (torsion ou compression). Leur caractérisation expérimentale par des courbes effort–déflection met en évidence des comportements non linéaires différents. L’étude expérimentale d’une transmission pour les 2 types de tendeurs et un tendeur fixe permet d’identifier la contribution de chacun à la dynamique de l’ensemble. La transmission est composée de 4 poulies dont le tendeur reliées par une courroie. Les mesures de vitesses, de vibrations de courroie, de couples et d’effort sont basées sur le principe d’échantillonnage angulaire. Les résultats obtenus montrent que l’utilisation de tendeurs diminue et sature l’amplitude des vibrations longitudinales, décale les zones d’instabilités des vibrations transverses vers des fréquences plus hautes et limite le glissement poulie - courroie

Identification of the non-linear hysteretic behavior of a belt tensioner

Mechanical tensioners are widely used in belt drive systems of automotive engines. They act to maintain a minimum tension in the slack span and to decrease transverse belt vibrations. They are composed of an idler pulley, an arm lever and a torsional springThe paper deals with the modeling of the dynamic behaviour of a tensioner. First an experimental investigation permits the characterisation of the tensioner: it is subjected to a force-deflection test carried out using a specific experimental set-up equipped with an electrodynamic shaker. The hysteretic loops are measured for several deflection amplitudes and forcing frequencies. Then, the experimental characterization permits identifying the parameters required by the original hysteretic model, and classical models like the Dahl’s model. The last part is devoted to the comparison of the hysteretic loops given by the tested models and the experiment

Dynamics of Torsional Vibration Damper (TVD) pulley, implementation of a rubber elastomeric behavior, simulations and experiments

International audienceIn this work, the Torsional Vibration Damper (TVD) rubber ring viscoelastic-material properties are determined based on Dynamical Mechanical Analysis (DMA) measurements and master curves reconstructions using thermo-simplicity principle. The elastomeric constitutive behavior is then implemented in the torsional vibration damper's equation of motion and the frequency response is simulated so that enhanced physical representation of the TVD dynamics can be achieved. Major differences in the TVD frequency response are highlighted and analyzed whether or not the viscoelastic material properties (elasticity modulus and damping) are considered constant or frequency and temperature dependent

Non Linearity of the Ball/Rubber Impact in Table Tennis: Experiments and Modeling

AbstractAlong with comfort, the speed is a key metric used to qualify the performance of a table tennis racket. The restitution coefficient which corresponds to the ratio between the velocities of the ball right before and after normally impacting the racket relates to the speed performance: the higher the restitution coefficient, the greater the speed. Thus, understanding the normal impact problem is key and suggests investigating the effects of the intrinsic properties and architectures of the constituents of the racket. In this work, both experimental and numerical studies were pursued. Experimentally, normal impact tests were performed for varying launching velocities on samples made of isolated or associated constituents of a table tennis racket and the restitution coefficients calculated. Numerically, 3D finite elements simulations were conducted to replicate the normal impact conditions while incorporating the time-dependent constitutive behavior of the polymeric elements contributing during the impact: the racket constituents (the foam and the compact) and the ball. The restitution coefficients are seen to decrease with increasing launching velocity, while being minimum when the two racket polymeric constituents are associated. A fair agreement is obtained with the FE simulations in which the sample/ball contact zone is identified as a ring with its mean radius increasing till the maximum crushing. Ultimately, additional FE calculations confirm that the friction plays a key role in the energy dissipation process, alongside with the rate-dependent behavior and architecture of the polymeric constituents