scholarly journals Analytical model for determinate static load capacity between roller and bolt in thread roller screw base on Hertz theory

Mechanik ◽  
2015 ◽  
pp. 146/41
Author(s):  
Stanisław Warchoł
Keyword(s):  
Analytical Model ◽  
Static Load ◽  
Load Capacity ◽  
Hertz Theory ◽  
Roller Screw

scholarly journals Contact Analysis and Static Load Carrying Capacity of Planetary Roller Screw Mechanism

2020 ◽  
Author(s):  
Nam Su Kim ◽  
Kyongho Kim ◽  
Sinhyok Jong
Keyword(s):  
Finite Element ◽  
Contact Stress ◽  
Carrying Capacity ◽  
Static Load ◽  
Load Capacity ◽  
Load Carrying Capacity ◽  
Elastic Plastic ◽  
Load Carrying ◽  
Roller Screw ◽  
Screw Mechanism

Abstract This paper aims to investigate the contact characteristics and static load carrying capacity of planetary roller screw mechanism (PRSM). Compared to the ball screw mechanism, the advantages of the PRSM are high stiffness, high load capacity, long travel life and compact structure, etc., since the PRSM possesses more contact points than ball screws in a comparable size. The actuated load is carried through the threaded surface contacts of the screw, the rollers and the nut and the contact characteristics of these components are very important for studying the wear, transmission accuracy and efficiency of a PRSM. Prior work has neglected to take a fundamental approach towards understanding the elastic-plastic contact characteristics of threaded surfaces under high loads and it is closely related to the static load carrying capacity of PRSM. Accordingly, in this paper, the contact characteristics of PRSM under the different working loads are modeled based on Hertz contact theory and the calculation formulas between normal force of thread turns and the elastic-plastic contact stress and deformation are derived. Then, it goes further to derive a calculation method of static load carrying capacity of PRSM based on simplified model of static load distribution. Finally, a verification model is developed by finite element method (FEM) to perform contact stress and strain analysis of PRSM. Besides, through the comparison of the results between the theory model and ANSYS Workbench finite element model verify the reliability of the theory.

Lastverteilung in Planetenrollengewindetrieben/Description of the load distribution in planetary roller screws

2020 ◽  
Vol 110 (05) ◽  
pp. 322-327
Author(s):  
Christian Brecher ◽  
Thomas Frenken ◽  
Gabriel Axelrad ◽  
Stephan Neus
Keyword(s):  
Load Distribution ◽  
Load Capacity ◽  
Calculation Model ◽  
Axial Stiffness ◽  
Contact Points ◽  
Calculation Results ◽  
Roller Screw ◽  
The Individual ◽  
Individual Contact ◽  
High Load Capacity

Planetenrollengewindetriebe finden aufgrund ihrer hohen Tragfähigkeit Anwendung in Bereichen, in denen Kugelgewindetriebe an ihre Lastgrenzen stoßen. Um ein Berechnungsmodell für Planentenrollengewindetriebe zu entwickeln, wurden Berechnungsmethoden zur Beschreibung der Lastverteilung innerhalb des Planetenrollengewindetriebs entwickelt. Mit diesen lassen sich die in den einzelnen Kontaktpunkten wirkenden Kräfte sowie die Verlagerungen des Gewindetriebs bestimmen. Die Berechnungsergebnisse werden unter anderem für die Berechnung der statischen axialen Steifigkeit und der Ermüdungslebensdauer benötigt.   Due to their high load capacity, planetary roller screws are used in areas where ball screws reach their load limits. To develop a calculation model for planetary roller screws, calculation methods to describe the load distribution within the planetary roller screw were developed in this step. With these methods, the forces acting in the individual contact points as well as the displacements of the screw drive can be determined. The calculation results are required, among other things, for the calculation of static axial stiffness and fatigue life.

On the Axisymmetric Response of a Damaged Flexible Pipe

2014 ◽  
Author(s):  
José Renato M. de Sousa ◽  
Carlos Magluta ◽  
Ney Roitman ◽  
George C. Campello
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Load Capacity ◽  
High Stress ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Experimental Measurements ◽  
Fe Model ◽  
Flexible Pipe ◽  
High Stress Concentration

This work focuses on the structural analysis of a damaged 9.13″ flexible pipe to pure and combined axisymmetric loads. A set of experimental tests was carried out considering one up to ten broken wires in the outer tensile armor of the pipe and the results obtained are compared to those provided by a previously presented finite element (FE) model and a traditional analytical model. In the experimental tests, the pipe was firstly subjected to pure tension and, then, the responses to clockwise and anti-clockwise torsion superimposed with tension were investigated. In these tests, the induced strains in the outer armor were measured. Moreover, the axial elongation of the pipe was monitored when the pipe is subjected to tension, whilst the twist of the pipe was measured when torsion is imposed. The experimental results pointed to a slight decrease in the stiffness of the pipe with the increasing number of broken wires and, furthermore, a redistribution of forces among the intact wires of the damaged layer with high stress concentration in the wires close to the damaged ones. Both theoretical models captured these features, but, while the results obtained with the FE model agreed well with the experimental measurements, the traditional analytical model presented non-conservative results. Finally, the results obtained are employed to estimate the load capacity of the pipe.

Design and Load Rating Analysis of the Elastic Support for a Large Roller Bearing

1970 ◽  
Vol 92 (1) ◽  
pp. 113-117 ◽  
Author(s):  
W. D. Anderson ◽  
C. L. Dellinger
Keyword(s):  
Static Load ◽  
Load Capacity ◽  
Roller Bearing ◽  
Basic Oxygen Furnace ◽  
Computer Assisted ◽  
Curved Beam ◽  
Load Rating ◽  
Basic Oxygen ◽  
Beam Design ◽  
Assisted Analysis

The Basic Oxygen Furnace comprises a tiltable vessel supported by two trunnions in large roller bearings. To accommodate thermal expansion, the floating bearing is mounted on a deep curved beam which moves axially on two linear bearings. Under loads of 1 to 2 million pounds, the elastic deflection of this beam alters the static load capacity of the roller bearing. This paper describes a computer assisted analysis based on Castigliano’s First Theorem for determining the effective bearing capacity, and secondly for optimizing the beam design.

Increasing the load capacity and rigidity of roller–screw mechanisms by adjusting the screw surfaces

2016 ◽  
Vol 36 (5) ◽  
pp. 345-351 ◽  
Author(s):  
V. V. Morozov ◽  
V. I. Panyukhin ◽  
A. V. Zhdanov
Keyword(s):  
Load Capacity ◽  
Roller Screw

A New Bump-Type Foil Bearing Structure Analytical Model

2007 ◽  
Vol 129 (4) ◽  
pp. 1047-1057 ◽  
Author(s):  
Sébastien Le Lez ◽  
Mihaï Arghir ◽  
Jean Frene
Keyword(s):  
Analytical Model ◽  
Degrees Of Freedom ◽  
Load Capacity ◽  
Reaction Force ◽  
Analytical Models ◽  
Experimental Investigations ◽  
Underlying Structure ◽  
Static System ◽  
Theoretical Approaches ◽  
Foil Bearing

A gas bearing of bump foil type comprises an underlying structure made of one or several strips of corrugated sheet metal covered by a top foil surface. The fluid film pressure needs to be coupled with the behavior of the structure for obtaining the whole bearing characteristics. Unlike in classical elasto-aerodynamic models, a foil bearing (FB) structure has a very particular behavior due to friction interfaces, bump interactions, and nonisotropic stiffness. Some authors have studied this complex behavior with the help of three-dimensional finite element simulations. These simulations evidenced a lack of reliable analytical models that can be easily implemented in a FB prediction code. The models found in the literature tend to overestimate the foil flexibility because most of them do not consider the interactions between bumps that are highly important. The present work then develops a model that describes the FB structure as a multidegree of freedom system of interacting bumps. Each bump includes three degrees of freedom linked with elementary springs. The stiffnesses of these springs are analytically expressed so that the model can be adjusted for any dimensions and material properties. Once the stiffness matrix of the whole FB structure is obtained, the entire static system is solved taking friction into account. Despite its relative simplicity, comparisons with finite elements simulations for various static load distributions and friction coefficients show a good correlation. This analytical model has been integrated into a foil bearing prediction code. The load capacity of a first generation foil bearing was then calculated using this structure model as well as other simplified theoretical approaches. Significant differences were observed, revealing the paramount influence of the structure on the static and dynamic characteristics of the foil bearing. Some experimental investigations of the static stiffness of the structure were also realized for complete foil bearings. The structure reaction force was calculated for a shaft displacement with zero rotation speed, using either the multidegree of freedom model or the usual stiffness formulas. The comparisons between theoretical and experimental results also tend to confirm the importance of taking into account the bump interactions in determining the response of the structure.

Design of an Improved Nonlinear Disc Spring Vibration Isolator

2016 ◽  
Vol 835 ◽  
pp. 643-648
Author(s):  
Jia Fang ◽  
Huang Dong
Keyword(s):  
Vibration Isolation ◽  
Static Load ◽  
Load Capacity ◽  
Hysteresis Curve ◽  
Mechanical Equipment ◽  
Vibration Isolator ◽  
Element Analysis ◽  
Heavy Load ◽  
New Type ◽  
Disc Spring

An improved nonlinear vibration isolator is proposed in this paper. It uses the exact solution derived load-displacement hysteresis curve formula based on energy method to calculate disc spring, combined with the finite element analysis. The static load capacity and dynamic mechanical property of this new type disc spring vibration isolator is validated through the static load tests or fatigue analysis. Compared with the rubber vibration isolator, the conclusion can be found: the new type vibration isolator has wider scope of vibration isolation, and is better in low frequency vibration isolation. These research achievements are of significant importance in the vibration isolation of heavy load and great shock mechanical equipment.

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