Analysis, Design, and Modeling of a Rotary Vane Engine (RVE)

2004 ◽  
Vol 126 (4) ◽  
pp. 711-720 ◽  
Author(s):  
B. V. Librovich ◽  
A. F. Nowakowski
Keyword(s):  
Coulomb Friction ◽  
Simple Structure ◽  
Dynamical Behavior ◽  
Friction Model ◽  
Reciprocating Engine ◽  
Torque Transmission ◽  
Analysis Design ◽  
Work Units ◽  
Coulomb Friction Model ◽  
Moving Parts

This paper introduces a mathematical model to analyze the dynamic behavior of a novel rotary vane engine (RVE). The RVE can be considered to have a number of advantages when compared to a majority of other reciprocating engine types. The advantages are found in the simple structure and the small number of moving parts. In this paper the geometrical structure and dynamical behavior of engines with a different number of work units is considered in detail. This has been examined through a study of torque transmission with a particular reference to how this is affected by the noncircular geometry of gear pitch curves. Using the Coulomb friction model, consideration has been given to the mechanical power loss due to friction in different parts of the engine, which must be taken into account. The study also proposes a possible method for balancing of asymmetric cogwheels. The analysis concludes that by using an appropriate design and arrangement of cogwheels and all moving parts, vibration can be attenuated due to impulsive gas torque.

Dynamic Behaviour of Rotary Vane Engines With One, Two and Four Work Units

Volume 2 ◽  
2004 ◽  
Author(s):  
B. V. Librovich ◽  
A. F. Nowakowski
Keyword(s):  
Mathematical Model ◽  
Simple Structure ◽  
Dynamic Behaviour ◽  
Geometrical Structure ◽  
Dynamical Behaviour ◽  
Reciprocating Engine ◽  
Torque Transmission ◽  
Work Units ◽  
Moving Parts

A mathematical model to analyse the dynamic behaviour of a novel rotary vane engine (RVE) is introduced in this paper. The RVE have a number of advantages compare to a majority of other reciprocating engine types. The main advantages are a simple structure and the small number of moving parts. The geometrical structure and dynamical behaviour of engines with a different number of work units is considered in detail. This has been examined through a study of torque transmission with a particular reference to how this is affected by the non-circular geometry of gear pitch curves. A possible method for balancing of asymmetric cogwheels have been proposed as well. The analysis concludes that by using an appropriate design and arrangement of cogwheels and all moving parts, vibration due to impulsive gas torque can be attenuated.

Control for Robots With Braking Actuators in a Uniform Force Field

2015 ◽  
Author(s):  
Erlend Framstad ◽  
Mark D. Bedillion
Keyword(s):  
Force Field ◽  
Control Strategy ◽  
Coulomb Friction ◽  
Energy Equation ◽  
High Accuracy ◽  
Friction Model ◽  
Second Law ◽  
Inclined Plane ◽  
Position And Orientation ◽  
Coulomb Friction Model

This paper concerns the control strategy of a robot with controllable brakes placed in a uniform force field. Without loss of generality this force field is assumed to be gravity, and the robot to be an object resting on an inclined plane. The controller’s objective is then to use the brakes to lead the robot into a desired position and orientation. The system’s dynamics were derived from Newton’s second law with a Coulomb friction model. The controller was derived from geometric properties and the energy equation. The controller was then tested using Matlab and Simulink on the dynamics that were derived. The results of the simulation shows high accuracy even with some disturbances, and uncalibrated parameters.

Asperity Spring Friction Model With Application to Belt-Drives

2003 ◽  
Author(s):  
Tamer M. Wasfy
Keyword(s):  
Finite Element ◽  
Coulomb Friction ◽  
Friction Model ◽  
Belt Drive ◽  
Finite Element Code ◽  
Time Step ◽  
Stick Slip ◽  
Normal Contact ◽  
Belt Drives ◽  
Coulomb Friction Model

An asperity spring friction model that uses a variable anchor point spring along with a velocity dependent force is presented. The model is incorporated in an explicit timeintegration finite element code. The friction model is used along with a penalty-based normal contact model to simulate the dynamic response of a two-pulley belt-drive system. It is shown that the present friction model accurately captures the stick-slip behavior between the belt and the pulleys using a much larger time-step than a pure velocity-dependent approximate Coulomb friction model.

scholarly journals Recent Developments and Trends in the Friction Testing for Conventional Sheet Metal Forming and Incremental Sheet Forming

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 47 ◽  
Author(s):  
Tomasz Trzepiecinski ◽  
Hirpa G. Lemu
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Coulomb Friction ◽  
Sheet Forming ◽  
Friction Model ◽  
Friction Resistance ◽  
Friction Testing ◽  
Coulomb Friction Model

Friction is the main phenomenon that has a huge influence on the flow behavior of deformed material in sheet metal forming operations. Sheet metal forming methods are one of the most popular processes of obtaining finished products, especially in aerospace, automobile, and defense industries. Methods of sheet forming are carried out at different temperatures. So, it requires tribological tests that suitably represent the contact phenomena related to the temperature. The knowledge of the friction properties of the sheet is required for the proper design of the conditions of manufacturing processes and tools. This paper summarizes the methods used to describe friction conditions in conventional sheet metal forming and incremental sheet forming that have been developed over a period of time. The following databases have been searched: WebofKowledge, Scopus, Baztool, Bielefield Academic Search Engine, DOAJ Directory of Open Access Journals, eLibrary.ru, FreeFullPdf, GoogleScholar, INGENTA, Polish Scientific Journals Database, ScienceDirect, Springer, WorldCat, WorldWideScience. The English language is selected as the main source of review. However, in a limited scope, databases in Polish and Russian languages are also used. Many methods of friction testing for tribological studies are selected and presented. Some of the methods are observed to have a huge potential in characterizing frictional resistance. The application of these methods and main results have also been provided. Parameters affecting the frictional phenomena and the role of friction have also been explained. The main disadvantages and limitations of the methods of modeling the friction phenomena in specific areas of material to be formed have been discussed. The main findings are as follows—The tribological tests can be classified into direct and indirect measurement tests of the coefficient of friction (COF). In indirect methods of determination, the COF is determined based on measuring other physical quantities. The disadvantage of this type of methods is that they allow the determination of the average COF values, but they do not allow measuring and determining the real friction resistance. In metal forming operations, there exist high local pressures that intensify the effects of adhesion and plowing in the friction resistance. In such conditions, due to the plastic deformation of the material tested, the usage of the formula for the determination of the COF based on the Coulomb friction model is limited. The applicability of the Coulomb friction model to determine the COF is also very limited in the description of contact phenomena in hot SMF due to the high shear of adhesion in total contact resistance.

Modelling of the Steel Pushing V-Belt Continuously Variable Transmission

1994 ◽  
Vol 208 (1) ◽  
pp. 13-27 ◽  
Author(s):  
J D Micklem ◽  
D K Longmore ◽  
C R Burrows
Keyword(s):  
Mathematical Model ◽  
Coulomb Friction ◽  
Continuously Variable Transmission ◽  
Friction Model ◽  
Full Potential ◽  
Shear Connection ◽  
System A ◽  
Variable Transmission ◽  
Coulomb Friction Model ◽  
Good Agreement

The steel pushing V-belt continuously variable transmission (CVT) is now commercially available in the automobiles of a number of manufacturers but to date it has not led to a significant reduction in fuel consumption. To develop its full potential it is necessary to have a good mathematical model of the system. A number of models have been described in recent years but all make use of a Coulomb friction model for the shear connection between the belt and the pulleys. This paper proposes a friction model based on elastohydrodynamic theory. It is shown that there is good agreement between measured and calculated slip values for the transmission which justifies use of the model.

Experimental and Numerical Investigations on Frictional Behaviour under Consideration of Varying Tribological Conditions

2014 ◽  
Vol 966-967 ◽  
pp. 270-278 ◽  
Author(s):  
Marion Merklein ◽  
Fabian Zöller ◽  
Vera Sturm
Keyword(s):  
Coulomb Friction ◽  
Fe Simulation ◽  
Friction Model ◽  
Body Parts ◽  
Numerical Investigations ◽  
Drawing Test ◽  
Strip Drawing ◽  
Complex Test ◽  
Coulomb Friction Model ◽  
Frictional Behaviour

In present time the FE-simulation of body parts in sheet metal drawing processes has to be continuously improved to increase the prediction accuracy. The objective of this paper is to describe a methodology to improve the simulation by mapping the complex tribological conditions of the process in the simulation. This methodology focuses on the dependency of influencing parameters on the friction coefficient. The influence respectively the dependency of these factors has been investigated, both in an experiment of a plane strip drawing test and in a FE-simulation of this test. With the sensitivity analysis in the numerical simulation it is possible to compare the implemented Coulomb-friction-model against the experimental results. The results of the experimental and numerical investigation show the need of further investigations on a more geometrical complex test to prove if it is possible to transfer the knowledge and dependencies that has been found in the experiment with the strip drawing test to a more geometrical complex test.

Analysis of Actively Controlled Coulomb Damping for Rotating Machinery

1999 ◽  
Author(s):  
John M. Vance ◽  
Luis A. San Andrés
Keyword(s):  
Coulomb Friction ◽  
Critical Speed ◽  
Vibration Suppression ◽  
Friction Model ◽  
Rotating Machinery ◽  
Friction Damper ◽  
Control Laws ◽  
Coulomb Damping ◽  
Coulomb Type ◽  
Coulomb Friction Model

Attempts have been made in the past to use Coulomb damping for vibration suppression in rotating machinery. Typically, a dry friction damper is designed to operate on a flexible bearing support. These designs have usually been unsuccessful in practice, partly because the Coulomb coefficient changes with temperature, with ingress of dirt or lubricant, and with the surface wear conditions. It is known that purely Coulomb damping forces cannot restrain the peak rotor whirl amplitudes at a critical speed. The invention of a disk type of electroviscous damper, utilizing a fluid with electrorheological (ER) properties, has recently revived the interest in Coulomb type dampers. Several investigations have suggested that a Coulomb friction model was the best representation for an ER damper with voltage applied. This model was used to study the feasibility of developing actively controlled bearing dampers for aircraft engines. This paper analyzes the imbalance response of two different rotordynamic models with Coulomb friction damping and shows the benefit of adding active control. Control laws are derived to achieve minimum rotor vibration amplitudes while avoiding large bearing forces over a speed range that includes a critical speed. The control laws are derived for purely Coulomb type of damping and assuming a combination of Coulomb and viscous damping effects. It is shown that the most important feature of Coulomb damping for minimal rotordynamic amplitude response is the control of rotor support stiffness, i.e. leading to the relocation of critical speeds, rather than control of a damping coefficient.

Evaluation of the Coulomb Friction Coefficient by the Erichsen Test

2013 ◽  
Vol 365-366 ◽  
pp. 1190-1193 ◽  
Author(s):  
Gillo Giuliano
Keyword(s):  
Friction Coefficient ◽  
Lateral Surface ◽  
Aluminium Alloys ◽  
Coulomb Friction ◽  
Experimental Tests ◽  
Friction Model ◽  
Model Coupling ◽  
Cu Alloy ◽  
Coulomb Friction Model ◽  
Erichsen Test

In this study, the Erichsen test is used to identify the friction coefficient of the Coulomb friction model coupling experimental tests results with numerical ones. The evaluation of the Coulomb friction coefficient is based on the distance measured between the thinnest area of the specimen and the lateral surface of the blankholder. Two types of aluminium alloys, AA 2017 Al-Cu alloy and AA 5083 Al-Mg alloy, with thickness of 1.0 mm are selected as the experimental materials for Erichsen test. Specimens are tested in unlubricated condition as well as using two different lubricants, namely Grease LB4 and Mexmoly.

A Model for Friction in Metal Forming

1994 ◽  
Vol 116 (1) ◽  
pp. 8-13 ◽  
Author(s):  
William T. Carter
Keyword(s):  
Plastic Deformation ◽  
Metal Forming ◽  
Coulomb Friction ◽  
Hydrostatic Stress ◽  
Normal Component ◽  
Friction Model ◽  
Total Stress ◽  
Coulomb Friction Model ◽  
Bound Analysis

The role of hydrostatic stress on the plastic deformation of asperities is examined in the context of the adhesion theory of friction. A lower bound analysis gives the frictional shear strength to be proportional to the normal component of the deviatoric stress, rather than the total stress as is currently held in the Coulomb friction model. When applied to specific regimes, the new model is shown to agree qualitatively with various existing models for friction, including the Coulomb and Prandtl rules.

scholarly journals Friction compensation using Coulomb friction model with zero velocity crossing estimator for a force controlled model in the loop suspension test rig

2015 ◽  
Vol 230 (12) ◽  
pp. 2028-2045 ◽  
Author(s):  
Pooh Eamcharoenying ◽  
Andy Hillis ◽  
Jos Darling
Keyword(s):  
Coulomb Friction ◽  
Tracking Error ◽  
Force Sensor ◽  
Friction Model ◽  
Friction Compensation ◽  
Test Rig ◽  
Zero Crossing ◽  
Force Tracking ◽  
Coulomb Friction Model ◽  
Suspension Test

This paper presents a method of friction compensation for a linear electric motor in a model in the loop suspension test rig. The suspension consists of a numerically modeled spring and damper, with inputs of suspension motion. The linear motor is force controlled using a force sensor to track the output of the numerical model. The method uses a Coulomb friction model and applies a feedforward step signal when velocity zero crossing occurs. Velocity zero crossing estimation is achieved using an algorithm based on measured feedback velocity and force. Experimental results indicate reduction of force tracking error caused by Coulomb friction leading to improved test rig accuracy.

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