mecanisme
DESCRIPTION
Curs de mecanisme an 2TRANSCRIPT
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ATR Lectures, lab, project
Lectures 3h: Friday 13.30 – 16.20, venue: G P 3/H P 13
Laboratory work / Project: Mechanical Engineering Wednesday 11.40-
13.20, venue G P 3 / L II 10 Automotive Engineering Wednesday 13.30-
15.10, venue G P 3 / L II 10 Final grade: Project – (33%) Exam (theory and application) – (66%)
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ATR Subjects - Lecture I
Introduction. Objectives of this course. History of Mechanism and Machine
Science Study of mechanisms: analysis and
synthesis Study of mechanisms: structure,
kinematics, dynamics Examples
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ATR The principal objectives of this course are:
To develop your understanding of the fundamentals of kinematics and dynamics of mechanisms.
Gain experience using computer software to facilitate the design and analysis of simple and complex mechanisms.
Gain practical working knowledge, through design project of some common linkages.
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ATR Course Objectives
In this course, we will study the motion of mechanisms and machines (kinematics)
Mobility Displacement, velocity and acceleration
analysis Understand the behavior of existing designs Design of mechanisms Gears Cams
Machine elements are assumed to be rigid
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ATR Course Outline
• Introduction & Formal Definitions• Linkage & Mobilities• Kinematics: Position Analysis• Velocity and Acceleration Analysis• Dynamics• Graphical and Analytical Linkage Synthesis• Gears• Cam Design
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ATR Definition of Mechanism
A device that transforms motion to some desirable pattern
Oscillation motion of the piston translate to rotational motion of the crank shaft (engine)
Rotational motion of the crank shaft translates to Oscillation motion of the piston (pump)
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ATR Mechanism Analysis and Synthesis
Analysis – given a mechanism, perform kinematics and kinetics analysis Establishing the structural, kinematic
and dynamic characteristics
Synthesis - design a new mechanism to perform a desired function
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Analysis Synthesis
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ATR Literature
Talabă, D., Mecanisme articulate. Proiectareasistată de calculator, Ed.Univ. Transilvania, 2004.
Alexandru, P. ş.a, Proiectarea funcţională a mecanismelor. Editura Lux Libris. 1999
Antonya, Cs., Simularea grafică a sistemelor de corpuri, Ed.Univ. Transilvania, 2004.
Erdman, A. G., Sandor, G. N., Kota, S., MechanismDesign: Analysis and Synthesis, Prentice Hall, 2001.
Haug, J.E., Computers Aided Kinematics andDynamics of Mechanical System, vol. I. Allyn andBacon, 1989.
Jalon, J.G., Bayo, E., Kinematic and DynamicSimulation of Multibody Systems – The real timechallenge, Springer-Verlag, 1994.
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ATR Literature
Uicker, J.J. Jr., Pennock, G.R. and ShigleyJ.E. Theory of Machines and Mechanisms, Oxford University Press, 2011
Myska, David H. Machines & Mechanisms:applied kinematic analysis, 2nd Ed.,Prentice Hall, 2002
Shabana, A. A., Dynamics of MultibodySystems, Cambridge University Press,2005
Waldron, Kenneth J. and Kinzel, Gary L.,Kinematics, Dynamics, and Design ofMachinery, John Wiley & Sons, Inc, 2004.
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ATR History of Mechanism and Machine Science
Archimedes (ca. 287–212 BC) systematized the design of simple machines and the study of their functions
Contributed greatly to the theory of the lever, screw, and pulley, although he did not invent any of these machines.
He is the founder of statics and of hydrostatics, and his machine designs fascinated subsequent writers
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ATR History of Mechanism and Machine Science
Heron of Alexandria (10–85 AD) wrote many books on Mathematics, Geometry and Engineering, which were in use till the medieval times.
His most important invention was the Aeolipile, the first steam turbine.
Other inventions include automated machines for temples and theaters, surveying instruments, and military machines and weapons.
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Agustin de Betancourt (1758–1824), together with Jose Maria de Lanz, is known as co-author of “Essai sur la composition des machines” (1808), considered to be the first modern treatise on machines and the first book that contains a proposal for the classification of mechanisms based on criteria of transformation of motion.
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History of Mechanism and Machine Science
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Franz Reuleaux(1829-1905) developed a system for classifying kinematic mechanisms and created hundreds of models to embody his basic machine elements.
History of Mechanism and Machine Science
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ATR Kinematics (History)
André-Marie Ampère (1775-1836) first used the word Cinematique (French), from the Greek word for motion, describes the study of motion without regard to forces.
Later Cinematique anglecized to kinematics and germanized to kinematik.
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ATR Kinematics (History)
• Robert Willis (1800-1875), Prof. of natural philosophy at the University of Cambridge, England, summarized the task of mechanical synthesis.
– Five different ways to obtain relative motions between input and output links:
1. Rolling contact2. Sliding contact3. Linkages4. Wrapping connectors (belts, chains)5. Tackle (rope or chain hoists)
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ATR Kinematics (History)
• Reuleaux (1829-1905), published Theoretitiche Kinematik in 1875, translated into English by Alexander Kennedy (1847-1928)
– This text became the foundation of modern kinematics.
• Reuleaux defined six basic mechanical components.
1. The link2. The wheel3. The cam4. The screw5. The ratchet (intermittent-motion devices)6. The belt
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http://www.iftomm.org International Federation for the Promotion of
Mechanism and Machine Science Technical Committee for Biomechanical Engineering Technical Committee for Computational Kinematics Technical Committee for Gearing and Transmissions Technical Committee for Linkages and Mechanical
Controls Technical Committee for Micromachines Technical Committee for Multi-body Dynamics Technical Committee for Reliability Technical Committee for Robotics and Mechatronics Technical Committee for Rotordynamics Technical Committee for Sustainable Energy Systems Technical Committee for Transportation Machinery Technical Committee for Tribology Technical Committee for Vibrations
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MECHANICSScience dealing with motion
DIVISIONS OF MECHANICSStatics – Deals with systems which
are not changing with time.
Dynamics – Deals with systems which are changing with time.
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DIVISIONS OF DYNAMICS
KINEMATICS – Deals with Motion and Time
THE STUDY OF MOTION WITHOUT REGARD TO FORCES (Kinema – Greek Word – Motion)
KINETICS (DYNAMICS) – Deals with Motion, Time and Forces.
THE STUDY OF MOTION AND ITS CAUSES (forces, mass, inertia)
Statics Kinematics DynamicsSTRUCTURE MECHANISM MACHINE
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ATR Theory of mechanisms
Structure of mechanisms
Kinematics of mechanisms
Dynamics of mechanisms
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ATR Examples
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ATR Examples
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ATR Steering mechanisms(Ackerman)
Curs Mecanisme
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ATR Suspension mechanisms
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ATR Windshield Wipers
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ATR Engine
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ATR Full car model
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ATR Software tools
MSC Software: ADAMS (Automatic Dynamic Analysis of Mechanical Systems)
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ATR Software tools
SIMPACK – INTEC GmbH
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ATR Software tools
LMS Virtual.Lab Motion
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ATR Software tools
SimMechanics – MATLAB Mathworks
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ATR Software tools
alaska Technical University of Chemnitz, Germany AUTOLEV OnLine Dynamics Inc., United States AutoSim Mechanical Simulation Corp., United States AVL EXCITE AVL, Austria CAMeL-View IXtronics GmbH, Germany COMPAMM CEIT, Spain Dynawiz Concurrent Dynamics International Hyperview Motionview Altair Engineering, United States MapleSim Maplesoft, Canada MECANO Samtech, Belgium MBDyn Politecnico di Milano, Italy MBSoft Universite Catholique de Louvain, Belgium NEWEUL University of Stuttgart, Germany RecurDyn Function Bay Inc., Korea RoboAnalyzer Avon Enterprises, India Robotran Universite Catholique de Louvain, Belgium SAM Artas Engineering Software, The Netherlands SD/FAST PTC, United States SimCreator Realtime Technologies Inc., United States SimMechanics The Mathworks, United States SPACAR University of Twente, The Netherlands TRUE True-World, France Universal Mechanism Bryansk State Technical University, Russia Working Model Knowledge Revolution, United States
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ATR Definitions - MACHINE
Machines are mechanical devices used to accomplish work, to transfer or transform energy to do useful work.
An assemblage of parts that transmit forces, motion and energy in a predetermined manner modifies mechanical energy and transmits
it in a more useful form
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ATR Definitions - MECHAMISN
A mechanism is a heart of a machine. It is the mechanical portion of the
machine that has the function of transferring motion and forces from a power source to an output.
Mechanism is a system of rigid elements (linkages) arranged and connected to transmit motion and/or force in a predetermined fashion.
Mechanism consists of linkages and joints. In contrast: Structure – a single body with
no motion / combination of bodies with no relative motion
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Mechanism and machine parts or linksmove with respect to one another, because adjacent links are connected by articulations called joints (kinematic pair)
A link is assumed to be completely rigid
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ATR Classification of Mechanisms
Based on the nature of output speed Uniform motion
mechanism - Equal Displacement For Equal Time Interval All Gear Drives
Non-uniform motion mechanism Unequal Displacement For Equal Time Interval Examples : Linkage Mechanisms Cam Mechanisms
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ATR Components of Mechanisms
Link / element
Kinematic pairs / joints
Kinematic chain
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TR The Slider-Crank Mechanism
Input link, crank
Coupler link, connecting rod
Output link, piston (slider)
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TR Categories of Mechanisms
Function generation mechanisms
Output is a specified function of input
Motion generation mechanisms
Path generation mechanisms
The orientation of the object is important, rigid body guidance
A point on a link moves on a specified path
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A function generator is a linkage in which the relative motion between links connected to the ground is of interest.
A four-bar hand actuated wheelchair brake mechanism
Function Generation Mechanisms
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TRFunction Generation Mechanisms
A four-bar drive linkage for a lawn sprinkler
Function Generation Mechanisms
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A four-bar function generation mechanism to operate an artificial hand used for gripping.
A four-bar function generation mechanism to lower an attic stairway.
Function Generation Mechanisms
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In motion generation, the entire motion of the coupler link is of interest (rigid body guidance).
Rollerblade brake system
Fixed pivot points
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3Moving joints
Motion Generation Mechanisms
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Four-bar automobile hood linkage design
Motion Generation Mechanisms
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Lift platform
Six bar5
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Microwave carrier to assist people on wheelchair
Six bar
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Motion Generation Mechanisms
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In path generation, we are concerned only with the path of a tracer point and not with the motion (rotation) of the coupler link.
Crane – straight line motion
Path generation mechanisms
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TR Straight line Mechanisms
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TR Straight line Mechanisms
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