Thermo-Mechanical Model of Ball Screw With Non-Steady Heat Sources

2007 ◽  
Author(s):  
Otakar Horejs
Keyword(s):  
Mechanical Model ◽  
Ball Screw ◽  
Heat Sources ◽  
Steady Heat

Erwärmung von Kugelgewindetrieben*/Heating of ball screws - Time- and position-dependent heat sources in thermal simulations and experiments

2015 ◽  
Vol 105 (07-08) ◽  
pp. 475-481
Author(s):  
W. Maier
Keyword(s):  
Ball Screw ◽  
Experimental Temperature ◽  
Heat Sources ◽  
Infrared Sensor ◽  
Transient Model ◽  
Ir Sensors ◽  
Thermal Transient ◽  
Thermal Simulations

In diesem Fachaufsatz wird die Entwicklung eines thermischen „Matlab Simscape“-Modells vorgestellt. Das geometrisch und zeitlich thermisch transiente Modell „SimTherm“ erlaubt die Berechnung der Erwärmung und Ausdehnung eines Kugelgewindetriebs. Das Modell wird anhand experimenteller Untersuchungen bezüglich der Temperaturverteilung validiert. Die Temperaturen der Kugelgewindetrieb-Spindel werden hierbei ortsvariabel mittels eines Infrarot (IR)-Sensors lokal auf der Spindeloberfläche ermittelt.   This paper presents the development of a thermal “Matlab Simscape“ model. The geometrically and timewise thermal-transient model called “SimTherm“ makes it possible to calculate the temperature and the expansion of ball screws. The model is validated with experimental temperature tests. The temperature of the ball screw spindle is established locally on the spindle surface by using an infrared sensor.

scholarly journals Experiment-based thermal behavior research about the feed drive system with linear scale

2018 ◽  
Vol 10 (11) ◽  
pp. 168781401881235
Author(s):  
Yang Li ◽  
Jun Zhang ◽  
Dongxu Su ◽  
Changxing Zhou ◽  
Wanhua Zhao
Keyword(s):  
Closed Loop ◽  
Great Influence ◽  
Drive System ◽  
Ball Screw ◽  
Heat Sources ◽  
Positioning Error ◽  
Thermally Induced ◽  
Feed Drive ◽  
Feed Drive System ◽  
Screw Feed

Positioning error of the feed drive system has great influence of the machining quality. In order to guarantee the positioning accuracy, the linear grating scale is adopted to form a full-closed loop. However, due to the inner heat sources and environmental temperature variations, the linear grating scale could expand and the thermally induced positional deviation is generated. In this article, temperatures and positional deviations of the ball screw feed drive system and the linear motor feed drive system equipped with linear scales were tested. The factors that affect the positioning error were analyzed. Then, the temperatures and positioning coordinates were used as inputs to build the thermally induced positional deviation model of full closed-loop feed drive system. Based on the model, coordinate values of the machine tool were adjusted and the compensation was implemented. The testing results verified that after compensation, the positional deviations were greatly reduced.

Characteristic Aircraft Landing Gear Thermo-Tribo-Mechanical Model

2012 ◽  
Author(s):  
Laurent Heirendt ◽  
Hugh H. T. Liu ◽  
Phillip Wang
Keyword(s):  
Mechanical Model ◽  
Structural Damage ◽  
Shock Absorber ◽  
Thermal Response ◽  
Landing Gear ◽  
Heat Sources ◽  
Sources And Sinks ◽  
Average Temperature ◽  
Aircraft Landing ◽  
Aircraft Landing Gear

A methodology for studying the characteristic thermal response of a landing gear (LG) shock absorber is presented. Rough runways induce high loads on the shock absorber bearings and because of high relative sliding speeds of the shock absorber piston, heat is dissipated which is known to have led to structural damage. In this work, an overall model has been developed that is used to outline the characteristics of the thermal behavior and identify the heat sources and sinks in the landing gear shock absorber. The developed thermo-tribo-mechanical model (TTM model) is subdivided into four parts, all using simplified but representative equations. Emphasis is placed on developing a methodological framework and studying the evolution of the average temperature in the TZI (thermal zone of interest) while taxiing and taking-off.

scholarly journals Ball screw unit precise modelling with dynamics of loads and moving heat sources taken into account

2019 ◽  
Vol 19 (4) ◽  
pp. 27-41
Author(s):  
Jerzy JEDRZEJEWSKI ◽  
Zbigniew KOWAL ◽  
Wojciech KWASNY ◽  
Zdzislaw WINIARSKI
Keyword(s):  
Heat Source ◽  
Thermal Behaviour ◽  
Ball Screw ◽  
Fe Model ◽  
Heat Sources ◽  
Positioning Error ◽  
Positioning Precision ◽  
Head Positioning ◽  
Work Cycle ◽  
The Impact

This paper deals with the precision modelling of the ball screw unit’s thermal behaviour in the turning centre and its impact on the tool head positioning error. The error components along controllable axes X and Z are described in detail using an FE model integrating the changes in thermal and force loads and deformations occurring during the motion of the nut as a heat source. The impact of the nut work cycle on the thermal deformations of the ball screw and the displacements of the slideways and the screw points along both the axes and on carriage positioning precision is demonstrated.

A Thermal Resistance Model for Problems Involving Chemical Reactions and Phase Transition

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Yoash Mor ◽  
Alon Gany
Keyword(s):  
Heat Transfer ◽  
Phase Transition ◽  
Thermal Resistance ◽  
Chemical Reactions ◽  
Heat Sources ◽  
Resistance Model ◽  
Resistance Approach ◽  
Transfer Problems ◽  
Thermal Resistors ◽  
Steady Heat

This paper formulates a modified thermal resistance model (MTRM) for dealing with heat transfer situations involving heat sources from chemical reactions or phase transition. The modified thermal resistance model describes the various heat transfer mechanisms by three common thermal resistors, radiation, convection, and conduction (in media with no internal mass diffusion), adding a new coupled thermal resistor that stands for conduction and enthalpy flow in the gas phase. Similarly to the classical thermal resistance approach, the present model is valid for one-dimensional, quasi-steady heat transfer problems, but it can also handle problems with an internal chemical heat generation source. The new thermal resistance approach can be a useful modular tool for solving relatively easily and quickly complex problems involving chemical reactions and phase transition, such as combustion problems.

Inverse Determination of Boundary Conditions and Sources in Steady Heat Conduction With Heat Generation

1996 ◽  
Vol 118 (3) ◽  
pp. 546-554 ◽  
Author(s):  
T. J. Martin ◽  
G. S. Dulikravich
Keyword(s):  
Heat Conduction ◽  
Boundary Conditions ◽  
Heat Conduction Problem ◽  
Analytic Solutions ◽  
Heat Sources ◽  
Two Dimensional ◽  
Simple Modification ◽  
Ill Posed ◽  
Steady Heat Conduction ◽  
Steady Heat

A Boundary Element Method (BEM) implementation for the solution of inverse or ill-posed two-dimensional Poisson problems of steady heat conduction with heat sources and sinks is proposed. The procedure is noniterative and cost effective, involving only a simple modification to any existing BEM algorithm. Thermal boundary conditions can be prescribed on only part of the boundary of the solid object while the heat sources can be partially or entirely unknown. Overspecified boundary conditions or internal temperature measurements are required in order to compensate for the unknown conditions. The weighted residual statement, inherent in the BEM formulation, replaces the more common iterative least-squares (L2) approach, which is typically used in this type of ill-posed problem. An ill-conditioned matrix results from the BEM formulation, which must be properly inverted to obtain the solution to the ill-posed steady heat conduction problem. A singular value decomposition (SVD) matrix solver was found to be more effective than Tikhonov regularization for inverting the matrix. Accurate results have been obtained for several steady two-dimensional heat conduction problems with arbitrary distributions of heat sources where the analytic solutions were available.

scholarly journals Experimental Determination of Entropy and Exergy in Low Cycle Fatigue

2019 ◽  
Author(s):  
Patrick Ribeiro ◽  
Johann Petit ◽  
Laurent Gallimard
Keyword(s):  
Mechanical Model ◽  
Heat Dissipation ◽  
Low Cycle Fatigue ◽  
Empirical Models ◽  
Heat Sources ◽  
Test Results ◽  
Cycle Fatigue ◽  
Mechanical Fatigue ◽  
Al 2024

Recent works in mechanical fatigue consider that a threshold of entropy exists, the fracture fatigue entropy. The determination of this quantity is usually done considering empirical models for the mechanical power estimation. In this paper, we experimentally observe the existence of a threshold of entropy and exergy in low cycle fatigue for a flat Al-2024 specimen avoiding the use of a model, solely measuring the heat generated during a fatigue test. Results are then compared considering various hypotheses (1D heat dissipation with convection and radiation considered as heat sources, and, heat transfer from a fin with convection and radiation as boundary conditions) to an empirical mechanical model known in the literature and deviations between them are discussed.

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