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Tutor

Assist. Prof. Athanasios Chasalevris

Contact

M: chasalevris@mail.ntua.gr

T: +30 210 772 3681

W: http://users.ntua.gr/chasalevris

A: NTUA School of Mechanical Engineering

Building E | Office E.317 | Office hours 14:00 - 16:00

DESCRIPTION

 

The course includes the following objectives:

1. Introduction to the design of Mechanisms: The study of motion, introduction to the kinematic and dynamic analysis, design steps and iterations in mechanisms, contraint requirements, kinematic link-chains-mechanisms and machines, mobility of mechanisms, kinematic inversion, kinematic pairs and joints

2. Groups of Mechanisms according to their operation and use: 4-bar linkage (parallel and non parallel, drag link, crank and rocker), slider crank mechanism, scotch yoke mechanism, quick return mechanisms, straight line mechanisms, parallel mechanisms (pantograph), toggle mechanisms, Oldham coupling, universal joints (Kardan joints), intermittent motion mechanisms (Geneva wheel-Malta cross), ratchets, elliptic trammel

3. Kinematic Analysis of Mechanisms: One Method is Taught: Vector analysis using the loop closure equation, for Position analysis - Velocity analysis - Acceleration analysis. Application in slider crank mechanism - 4/5-bar mechanism - mechanisms with sliding links - compound mechanisms

4. Dynamic Analysis of Mechanisms: One Method is Taught: Calculation of forces in mechanisms applying D' Alembert principle (converting dynamic problem to static). Application in slider crank mechanism - 4/5-bar mechanism - mechanisms with sliding links - compound mechanisms

5. Synthesis of mechanisms: Freudenstein's method and application in 4-bar mechanism

6. Gyroscopes and Gyroscopic Coupling: Calculation of the gyroscopic coupling moment in rotating elements, mechanisms based on gyroscopic phenomena

7. Flywheels: The problem of instantaneous fluctuation of speed - energy considerations and energy flow in mechanisms - design of flywheels

8. Design of Cams: Cam profiles and follower motions (linear, harmonic, cycloidal), the challenge for jerk-free motion- Cam design using polynomials

9. Instability in mechanisms: Speed governors and design for stability, the problem of instability in mechanism motions

10. Balancing of mechanisms: Static and dynamic balancing of mechanisms and of the 'rigid' machine

11. Analog computing mechanisms: Mechanisms as computers - the example of differential

12. Analysis and Synthesis of Mechanisms Using MATLAB: Kinematic/Dynamic analysis and synthesis of the slider-crank mechanism and the 4-bar mechanism and their inversions

Literature (active links for download)

[1] O. Vinogradov. Fundamentals of kinematics and dynamics of machines and mechanisms. CRC Press, 2000

[2] G. Martin. Kinematics and dynamics of machines, 2nd Edition. McGraw Hill, 1982

[3] R. Norton. Κινηματική και Δυναμική Μηχανών και Μηχανισμών, Πέμπτη Έκδοση. Κωδικός Βιβλίου στον Εύδοξο: 50657734

LECTURE NOTES

 

LECTURE NOTES ARE NOT AVAILABLE ONLINE YET

Lecture 1

Introduction to kinematic and dynamics analysis, and their role in the design of mechanisms, design steps, examples of mechanisms

 

Lecture 2

Mobility and degrees of freedom, kinematic inversion, Grashof's Law, kinematic pairs, kinematic links

 

Lecture 3

Basic operations of groups of mechanisms (4-bar,5-bar,slider-crank, and others)

 

Lecture 4

Kinematic analysis, basics in vector algebra, position analysis, steps in kinematic analysis

 

Lecture 5

Cases of kinematic analysis with respect to known and unknown parameters

 

Lecture 6

Kinematic analysis (position analysis) of slider-crank mechanism, and 4-bar mechanism

 

Lecture 7

Kinematic analysis (position analysis) of Scotch Yoke Mechanism, 5-bar mechanism, and compound mechanism. Calculation of trajectories

 

Lecture 8

Introduction to velocity analysis, Equations for velocities with respect to known and unknown parameters

 

Lecture 9

Velocity analysis of simple mechanisms, slider-crank and inversions, 4-bar, 5-bar, scotch yoke, and compound mechanisms

 

Lecture 10

Introduction to acceleration analysis, equations for acceleration with respect to known and unknown parameters

 

Lecture 11

Acceleration analysis of simple mechanisms, slider-crank and inversions, 4-bar, 5-bar, geneva wheel

 

Lecture 12

Introduction to Dynamic analysis, direct and inverse dynamics, force and moment vectors, free-body diagramm

 

Lecture 13

Inertial forces, applications in simple mechanisms, slider cracnk and inversions

 

Lecture 14

Mechanical advantage

 

Lecture 15

Instantaneous fluctuation of speed, Design of flywheels, requirement of flywheels in multi-cylinder engines, and power presses

 

Lecture 16

Dynamic analysis of 4-bar mechanism

 

Lecture 17

Introduction to Synthesis of Mechanisms. Example of Graphical method (overlay method). Analytical methods, the Freudenstein's method

 

Lecture 18

Design of Cams and followers

 

Lecture 19

Cam design, constant velocity profile, constant acceleration profile, simple harmonic profile, cycloidal profile, Polyonimic profile

 

Lecture 20

Evaluation of cam torque for flat faced cam, and cam-roller compound, calculation for manufacturing

 

Lecture 21

Gyroscopic phenomena in rotating elements, calculation of gyroscopic coupling

 

Lecture 22

Introduction to Balancing, definition of unbalance, static balancing, balancing rotating masses, unbalance Grades per ISO 1940-1

 

Lecture 23

Balancing of rotating mass in one plane. Introduction to balancing of reciprocating masses

 

Lecture 24

Dynamic equivalent system, balancing of mechanisms, application to simple mechanisms

 

HOMEWORK

Homework consists of 4 exercises aiming to the application of theory of Kinematics and Dynamics for the analysis of simple mechanisms. MATLAB software is used for this purpose. The students receive guidelines for the MATLAB script syntax in each exercise. Each exercise requires a 5-10 hrs study.

Homework contributes by 20% in the final grade and it is optional for ALL students

Homework 1

inertia forces in slider crank mechanism (crank-driven)

 

Homework 1

MATLAB file

 

Homework 2

contraint forces in slider crank mechanism (piston-driven), Energy flow and fluctuation of speed, design of flywheel

 

Homework 2

MATLAB file - contraint forces in slider crank mechanism (piston-driven), Energy flow and fluctuation of speed, design of flywheel

 

Homework 3

kinematics of 4-bar mechanism, contraint forces and bearing forces in 4-bar mechanism, Mechanical Advantage

 

Homework 3

MATLAB file

 

Homework 4

Design of cam-follower, calculation of torque, and power of mechanism

 

Homework 4

MATLAB file

 

TOOLS

Download MATLAB here

(NTUA IP Required)

Download OCTAVE here

(free download)

Download MATHEMATICA

(30 days trial)

GRADES

Αποτελέσματα εξετάσεων Ιουνίου 2020

AMΕΡΓΑΣΙΕΣ 20%ΕΞΕΤΑΣΗΤΕΛΙΚΟΣ
1234
209508499868.59
2103310----6.57
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2110002----8.59
2115052910577.58
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21136321010983.55
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21140311010786.57
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2114254710662.53
211426681010107.58
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211431536--5.56
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211433881010107.58
21143430109-3.54
2114379----6.57
2114388----4.55
2114390----2.53
211440310910-6.57
2114550----4.55
2115047----3.54
2115062910974.55
2115070----3.54
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2115836910977.58
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211601751010-3.54
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2116435----6.57
21164421010-98.59
2116463----1.52
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211647671010-3.54
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211702035565.55
2117026710968.59
211703781010-2.53
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2117080----2.53
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2117621010107.55.56
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2117639810784.55
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AMΕΡΓΑΣΙΕΣ 20%ΕΞΕΤΑΣΗΤΕΛΙΚΟΣ
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2118027578-4.55
21180281010--1010
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211803110101089.510
211803210108777
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211804899894.55
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211805386-101010
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211806410101078.59
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2118067101010101010
211806869--3.54
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21180721010995.56
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211808210109956
2118083----1.52
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211808510109104.56
211808708--2.53
211808910109-4.55
2118090101010-5.56
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AMΕΡΓΑΣΙΕΣ 20%ΕΞΕΤΑΣΗΤΕΛΙΚΟΣ
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21180938108-7.58
21180941010--5.56
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2118100101010103.55
2118101768106.57
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211810310107-7.58
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21181079109-3.54
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21181121010--5.56
211827271010-4.55
211827610101094.56
2118402----3.54
21184311010989.510
21184321010--7.58
21184339101098.59
2118435101010109.510
21185021010--2.53
21185036107-2.53
21185064107-9.510
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2118601----3.54
2118619810--4.55
211862510101098.59
211862799887.58
21186291010897.58
211863096--3.54
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21186371010--3.54
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2118640----6.57
2118641101010107.58
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211865010108-7.58
211865179--2.53
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211865381010-7.58
211865410108-2.53
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21186561010--2.53
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21186590101-4.55
2118663107996.57
211866459762.53
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211867229651.52
211867310108-4.55
211868310107-4.05
21186846109-9.510
21186851010--1.52
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21186871010778.59
211868810108-6.57
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2118695----2.53
211869710107-7.58
211869871010-7.58
211870310109-9.510
2118706895-5.56
21187151010--7.58
211871846--8.59
2118719810--2.53
211872110108-3.54
2118722----1.52
21187269101089.510
2118727710--8.59
21187281010--7.58
2118734810--5.56
211873910109-8.59
21187567108-6.57
21176915108102.54