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.

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.

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.

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.

scholarly journals Inclusion Modeling of Bucket Elevator Conveyor Chain Links

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Edward Yin ◽  
Onesmus Muvengei ◽  
John M. Kihiu
Keyword(s):  
Finite Element Method ◽  
Adverse Effect ◽  
Structural Integrity ◽  
Nonmetallic Inclusions ◽  
The Finite Element Method ◽  
Chain Link ◽  
Bucket Elevator ◽  
Cad Models ◽  
Chain Links ◽  
Material Saving

Inclusions, pores, and cracks which are defects in materials are important in determining the structural integrity and durability of components. Modeling accurately, these defects are hence of interest to both theorist and the practitioner. CAD models were designed using Autodesk Inventor software, and simulation was performed using ANSYS academic software. Material saving in design of conveyor chain links has gained popularity, and this has led to the introduction of necks in its geometry. However, the effect of necking on various parameters was not considered. Also, inclusions which are defects in material are known to have adverse effect on the conveyor chain link. It is, therefore, imperative to predict numerically, the effects that inclusions and necking have on conveyor chain links This paper focusses on modeling nonmetallic inclusions and also tests various models of different neck radii using the finite element method so as to predict its effect.

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.

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).

scholarly journals Mathematical Modeling of Open States in Double Stranded DNA Molecule Depending on 2H/1H Ratio

2019 ◽  
Vol 14 (2) ◽  
pp. 612-624 ◽  
Author(s):  
S.S. Dzhimak ◽  
M.I. Drobotenko ◽  
A.A. Basov ◽  
A.A. Svidlov ◽  
M.G. Baryshev
Keyword(s):  
Mathematical Modeling ◽  
Hydrogen Bond ◽  
Deuterium Atom ◽  
Living System ◽  
Dna Molecule ◽  
Dna Base Pair ◽  
A Chain ◽  
Time Required ◽  
Open States ◽  
Bond Disruption

The evaluation results of the possible deuterium atoms effect on the DNA base pair opening are presented in the article. The cause of these processes is the replacement of protium with deuterium atom due to the increase of energy required to break the hydrogen bond. These processes can be studied by method of mathematical modeling, with account of open states between base pairs being the key condition of the adequacy of the mathematical model of the DNA. The experiment data show that the presence of deuterium in a chain of nucleotides can cause - depending on the value of hydrogen bond disruption energy - both increase and decrease in probability of open states occurrence. For example: hydrogen bond disruption energy of 0.358·10-22 n·m, non-zero probability of open states occurrence is observed in case of the absence of deuterium in the molecule, and with hydrogen bond disruption energy of 0.359·10-22 n·m or more such probability equals zero. Also, when one deuterium atom is present in a molecule, non-zero probability is observed even with hydrogen bond disruption energy equal to 0.368·10-22 n·m (i.e. more than 0.358·10-22 n·m). Thus participation of deuterium atoms in the formation of hydrogen bonds of double helixes of a DNA molecule can cause the changes in the time required for transfer of genetic information, which can explain the effect of even minor deviations in deuterium concentration in a medium on metabolic processes in a living system.

scholarly journals LevioSAM: Fast lift-over of alternate reference alignments

2021 ◽  
Author(s):  
Taher Mun ◽  
Nae-Chyun Chen ◽  
Ben Langmead
Keyword(s):  
Population Genetics ◽  
Coordinate System ◽  
Data Structures ◽  
Succinct Data Structures ◽  
Reference Coordinate System ◽  
Link Type ◽  
A Chain ◽  
Time Required ◽  
Effective Use

AbstractMotivationAs more population genetics datasets and population-specific references become available, the task of translating (“lifting”) read alignments from one reference coordinate system to another is becoming more common. Existing tools generally require a chain file, whereas VCF files are the more common way to represent variation. Existing tools also do not make effective use of threads, creating a post-alignment bottleneck.ResultsLevioSAM is a tool for lifting SAM/BAM alignments from one reference to another using a VCF file containing population variants. LevioSAM uses succinct data structures and scales efficiently to many threads. When run downstream of a read aligner, levioSAM completes in less than 13% the time required by an aligner when both are run with 16 threads.Availabilityhttps://github.com/alshai/[email protected], [email protected]

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.

Sign in / Sign up

Export Citation Format

Share Document