Dynamics of CVT Chain Drives: Mechanichal Model and Verification

1997 ◽  
Author(s):  
Jürgen Srnik ◽  
Friedrich Pfeiffer
Keyword(s):  
Power Transmission ◽  
Contact Forces ◽  
Coulomb’S Friction ◽  
Joint Forces ◽  
Chain Link ◽  
Frictional Forces ◽  
Contact Situation ◽  
A Chain ◽  
Chain Drives ◽  
Chain Links

Abstract This paper deals with the dynamics of continuously variable (CVT) chain drives. According to the discrete structure of the chain, which causes the polygonal actions, the mechanical model contains each chain link and pulley as a separate body. While a chain link is part of a strand, only joint forces including friction act on the chain links, whereas in the contact situation additional impulsive and frictional forces in the contact zones between the chain link’s rocker pins and the tapered surfaces of the cone pulleys have to be taken into account. For the calculation of the contact forces Coulomb’s friction law as well as a time sparing continuous approximation are applied. Simulation results show the influence of the cone pulley’s deformation on the power transmission. They also show the repercussion of the polygonal action. Furthermore the chain’s pitch influence on the vibrational behavior of the transmission is discussed. A comparison of calculated and measured tensional forces verifies the model presented.

Out-of-Plane Bending Testing of Chain Links

2005 ◽  
Author(s):  
Cecil Melis ◽  
Phillipe Jean ◽  
Pedro Vargas
Keyword(s):  
Empirical Relationship ◽  
Chain Link ◽  
Out Of Plane ◽  
Bending Stresses ◽  
Test Frame ◽  
Scale Test ◽  
Plane Bending ◽  
A Chain ◽  
Chain Links ◽  
Mooring Chain

Several mooring chains of an off-loading buoy failed after only 8 months of service. These chains were designed according to conventional fatigue assessment using API RP 2SK T-N curves to a fatigue life or 20 years with a factor of safety equal to 3 on life. Of particular interest is that the mooring chain failure underwent significant mooring chain motions that caused interlink rotations. Although traditionally neglected, these interlink rotations, when combined with significant chain tensions can cause bending stresses in the chain links. In this paper we identify a mechanism, here identified as Out-of-Plane Bending (OPB) that explains the extensive fatigue damage causing the mooring chains of the off-loading buoy to fail. A full scale test frame was constructed that has the capacity of applying inter-link rotation to a pre-tensioned chain. Although the test frame limits the number of links that can be tested together as a chain, a significant amount of testing was performed for the following chain sizes: 1. 81 mm Studded Grade R3S. 2. 107 mm Studdless Grade RQ3. 3. 124 mm Studless Grade R4. 4. 146 mm Studless Grade RQ4. Various pretension levels were used, with instrumentation to extract link angles and chain link stresses. In this paper the OPB mechanism is explained, and the test frame and results are presented. An empirical relationship is found to predict the OPB stresses in the chain links as a function of pretension and inter-link rotation. The OPB stress relationship obtained was applied to the failed mooring chain of the off-loading buoy with reasonable agreement. To comply with Single Buoy Moorings (SBM) requirements addressing publication of internal research, many of the graphs included in this paper have had the stress values removed from the y-axis. However, with SBM’s management approval, some numerical references to stress amplitudes remain in the text. Overall, this limitation does not detract from the study, trends are evident and relevant comparisons can be made.

Dynamics of High Speed Roller Chain Drives

1995 ◽  
Author(s):  
Peter Fritz ◽  
Friedrich Pfeiffer
Keyword(s):  
High Speed ◽  
Contact Forces ◽  
System Structure ◽  
Unilateral Constraints ◽  
Roller Chain ◽  
Contact Configuration ◽  
Nonlinear Force ◽  
A Chain ◽  
The Impact ◽  
Chain Drives

Abstract This paper deals with roller chain drives applied in combustion engines. In order to find characteristics for an optimal design, all components of a chain drive are taken into account. For a detailed analysis of the chain strand vibrations and the contact configurations each chain link, sprocket and guide is treated as a separate body. A nonlinear force element describes the joint forces, including elasticity, damping, backlash and oil-displacement. To determine real contact forces between a link and a sprocket or a guide, the exact contour and the mutual dependence of the contacts are considered. The impact of one link may influence the other links in such a manner that their contact configuration may change. In the mechanical model these contacts are represented by unilateral constraints. Applying the formulation of the linear complementarities including additional inequality conditions, the determination of a valid contact configuration after a change in the system structure is simplified.

Influence of Clearance on the Dynamics of Chain CVT Drives

2006 ◽  
Author(s):  
Nilabh Srivastava ◽  
Yi Miao ◽  
Imtiaz U. Haque
Keyword(s):  
Dynamic Performance ◽  
Suitable Model ◽  
Multibody Model ◽  
System A ◽  
Automotive Transmission ◽  
Chain Link ◽  
Variable Transmission ◽  
Coulomb Approximation ◽  
A Chain ◽  
Chain Links

A continuously variable transmission (CVT) is an emerging automotive transmission technology that offers a continuum of gear ratios between desired limits. The present research focuses on developing models to understand the influence of clearance on the dynamic performance of a chain CVT drive. Clearances may arise in such a CVT during the assembly process or during extensive continual operation of the system, which further leads to wear and failure of the system. A detailed planar multibody model of a chain CVT is developed in order to accurately capture the dynamics characterized by the discrete structure of the chain, which causes polygonal excitations in the system. A suitable model for clearance between the chain links is embedded into this multibody model of the chain CVT. Friction between the chain link and the pulley sheaves is modeled using continuous Coulomb approximation theory. The mathematical models, the computational scheme, and the results corresponding to different loading scenarios are discussed. The results discuss the influence of clearance parameters on the dynamic performance, the axial force requirements, and the torque transmitting capacity of a chain CVT drive.

scholarly journals STRESS ANALYSIS AND TOPOLOGY OPTIMIZATION OF A CHAIN BUCKET ELEVATOR USING ANSYS

2021 ◽  
Vol 61 (1) ◽  
pp. 292-306
Author(s):  
Edward Yin ◽  
Emmanuel M. Seckley ◽  
Evans Kesse Asiedu ◽  
Stephen Cobbinah
Keyword(s):  
Topology Optimization ◽  
Maximum Load ◽  
Maintenance And Repair ◽  
Ratchet Mechanism ◽  
Repair Costs ◽  
Chain Link ◽  
Bucket Elevator ◽  
A Chain ◽  
Time Required ◽  
Chain Links

A failure of conveyor chain links in a production process can cause unscheduled shutdowns, which increase the throughput time coupled with damaged buckets and chain links, which increase maintenance and repair costs. Since failures of conveyor chains are inevitable, this research aims to modify the design of the chain bucket elevator by incorporating a ratchet mechanism, which will prevent the chain bucket assembly from dropping to the bottom of the chain bucket elevator whenever there is a chain-link failure and also avoid the jamming of the bucket chain assembly against one another when dropping to the bottom of the elevator during failure. The number of damaged buckets and chains will be minimal, thereby reducing the maintenance and repair costs. Also, the time required for replacing the failed chain link will be reduced, which in turn, will reduce the down-time, thereby increasing the production rate. The ratchet mechanism, which can withstand a maximum load of 38.10 kN, comprises a toothed wheel, a pawl, and a spring. An analytical method was employed for the initial analysis and the results were verified using the FEM. Topology Optimization was carried out on the beam and lever with results showing a 20% and 26% weight reduction from the original, respectively. The stresses induced in the beam and lever increased significantly by 36% and 47 %, respectively, because of the optimization, however, they remained within the acceptable limits.

Risk-Based Inspection Planning for Mooring Chain

2002 ◽  
Author(s):  
Jan Mathisen ◽  
Kjell Larsen
Keyword(s):  
Probabilistic Modelling ◽  
Structural Components ◽  
Inspection Planning ◽  
Single Chain ◽  
Chain Link ◽  
Northern North Sea ◽  
A Chain ◽  
Series Systems ◽  
Chain Links ◽  
Mooring Chain

The use of risk-based inspection planning for offshore structural components is becoming quite familiar. This paper describes an application of this technique to mooring chain. In many cases, the technique is based on probabilistic modelling of fatigue crack growth in the structural components, and updating of the failure probability on the basis of inspections. The extension of this basis from a single component to very many components is necessary to tackle series systems, such as mooring chain, where a fatigue fracture can arise in any chain link. The theoretical basis for the analysis is described, including details of the model for stochastic dependency between the chain links. Results are shown that compare failure probabilities for a single chain link and a chain segment. The effects of various levels of inspection coverage are illustrated. An example of a cost optimal inspection plan is developed for mooring chain on an FPSO in the northern North Sea.

Risk-Based Inspection Planning for Mooring Chain

2004 ◽  
Vol 126 (3) ◽  
pp. 250-257 ◽  
Author(s):  
Jan Mathisen ◽  
Kjell Larsen
Keyword(s):  
Probabilistic Modelling ◽  
Structural Components ◽  
Inspection Planning ◽  
Single Chain ◽  
Chain Link ◽  
Northern North Sea ◽  
A Chain ◽  
Series Systems ◽  
Chain Links ◽  
Mooring Chain

The use of risk-based inspection planning for offshore structural components is becoming quite familiar. This paper describes an application of this technique to mooring chain. In many cases, the technique is based on probabilistic modelling of fatigue crack growth in the structural components, and updating of the failure probability on the basis of inspections. The extension of this basis from a single component to very many components is necessary to tackle series systems, such as mooring chain, where a fatigue fracture can arise in any chain link. The theoretical basis for the analysis is described, including details of the model for stochastic dependency between the chain links. Results are shown that compare failure probabilities for a single chain link and a chain segment. The effects of various levels of inspection coverage are illustrated. An example of a cost optimal inspection plan is developed for mooring chain on an FPSO in the northern North Sea.

scholarly journals Oceanithermus desulfurans sp. nov., a novel thermophilic, sulfur-reducing bacterium isolated from a sulfide chimney in Suiyo Seamount

2004 ◽  
Vol 54 (5) ◽  
pp. 1561-1566 ◽  
Author(s):  
Koji Mori ◽  
Takeshi Kakegawa ◽  
Yowsuke Higashi ◽  
Ko-ichi Nakamura ◽  
Akihiko Maruyama ◽  
...  
Keyword(s):  
Sequence Similarity ◽  
Growth Conditions ◽  
Cellular Fatty Acid ◽  
Rrna Gene ◽  
Good Growth ◽  
Chain Link ◽  
Circular Structure ◽  
Hybridization Test ◽  
A Chain ◽  
Cellular Fatty Acid Profile

A novel thermophilic, microaerophilic, sulfur-reducing bacterium designated strain St55BT was isolated from a sulfide chimney in the hydrothermal field of Suiyo Seamount (Izu-Bonin Arc, Western Pacific). Cells of the isolate were rod-shaped and tended to form a chain-link circular structure (a rotund body) at exponential phase under good growth conditions. The isolate was a chemoheterotroph requiring yeast extract for growth. Although strain St55BT used oxygen as an electron acceptor, it could not form colonies in an oxygen concentration of more than 5 % (v/v). The isolate also used nitrate, nitrite or elemental sulfur in the absence of oxygen. A phylogenetic analysis based on the 16S rRNA gene sequence revealed that the isolate was closely related to Oceanithermus profundus, belonging to the phylum ‘Deinococcus–Thermus’ (sequence similarity 99·5 %). However, strain St55BT differed from O. profundus in terms of usage of electron donors, cellular fatty acid profile and DNA G+C content. In addition, a DNA–DNA hybridization test indicated low relatedness between the isolate and O. profundus. For the reasons given above, the name Oceanithermus desulfurans sp. nov. is proposed for strain St55BT (=NBRC 100063T=DSM 15757T).

Modeling of a Finger-Follower Cam System With Verification in Contact Forces

1993 ◽  
Author(s):  
Wensyang Hsu ◽  
Albert P. Pisano
Keyword(s):  
Constraint Equation ◽  
Contact Forces ◽  
Valve Train ◽  
Dynamic Responses ◽  
Valve Lift ◽  
Distributed Parameter ◽  
Contact Points ◽  
Frictional Forces ◽  
Contact Position ◽  
Force Data

Abstract A lumped/distributed-parameter, dynamic model is developed to investigate the dynamic responses of a finger-follower valve train with the effects of an oscillating pivot, frictional forces between sliding surfaces, and a hydraulic lash adjuster. Based on the measured force data at low speed, an algorithm is derived to determine the dynamic Coulomb friction coefficients around maximum valve lift simultaneously at three contact points. A constraint equation is formulated to find the contact position between the cam and the follower kinematically. This makes it possible for the model to simulate the dynamic response of the cam system when the pivot is moving. A hydraulic lash adjuster acting as the pivot of the follower is also modeled with the effects of oil compressibility and oil refill mechanism. The model is numerically integrated and shown to have good agreement between simulation results and experimental data of contact forces at three different speeds. The maximum operating speed is limited by valve toss, loss contact between components. The model predicts toss between the hydraulic lash adjuster and the follower at 2535 rpm, and experiment indicates toss starting at 2520 rpm of camshaft speed.

Probability of Load-Carrying Ability of Two-Profile Chain Drives

2000 ◽  
Author(s):  
Petro D. Kryvyy ◽  
Ihor M. Bey ◽  
Oksana I. Shymanska ◽  
Petro P. Kryvyy
Keyword(s):  
Measurement Procedure ◽  
Chain Drive ◽  
Distribution Law ◽  
Drive Roller ◽  
Load Carrying ◽  
A Chain ◽  
Dimension Type ◽  
Chain Drives ◽  
Unit Pressure

Abstract The analysis of the available calculation methods of chain-drives load-carrying ability is given according to the criterion of the tolerance unit pressure in a single profile chain joint [p]0. It is shown, that the values of [p]0 were determined according to the deterministic ideas without consideration of the distribution law of both random varieties of contact step of inner and outer rings and lengths of drive strands of the first and second profile of the chain drive. Probability task of determination of the tolerance unit pressure in two profile chain joints [p0]q is solved, when the structural, technological and physical-mechanical characteristic of the chain, that is, the lengths of drive strand of a chain-drive, accuracy of contact steps and stiffness of a drive roller chain are considered. The measurement procedure and the empirical dependencies for determination of drive roller chains deformation and stiffness are presented. As a result, the dependencies for the determination of [p0]q as the basic criterion according to which selection of a chain dimension-type, as well as characteristics used for the comparative estimation of a drive chain quality of different manufacturers when certain probability estimations are taken into consideration, were obtained.

On the Usage of Dynamic Vibration Absorbers for Reduction of Forced Vibrations of a System of Coupled Rigid Bodies

2009 ◽  
Author(s):  
Dmitry Chebanov ◽  
Alexander M. Kovalev ◽  
Irina A. Bolgrabskaya ◽  
Vladimir F. Shcherbak
Keyword(s):  
Forced Vibrations ◽  
Rigid Bodies ◽  
Vibration Absorbers ◽  
Constant Mass ◽  
External Perturbations ◽  
Dynamic Vibration ◽  
Dynamic Vibration Absorbers ◽  
Controlled Motion ◽  
A Chain ◽  
Chain Links

In this paper we study the problem of neutralizing the forced vibrations of a chain of heavy rigid bodies coupled by one-degree-of-freedom joints using dynamic vibration absorbers. Each absorber is modeled by a system that has a constant mass and is capable of making instantaneous changes in its stiffness. We propose and analyze several strategies for introducing the absorbers that differ from each other by the number of absorbers attached and the way they are positioned on the chain links. In particular, we suggest a way to choose the parameters of the absorbers so that their controlled motion totally compensates the effect of the external perturbations.

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