Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

MER 312: Dynamics and Kinematics

BY

Abraham Tchako, PhD

Fall 2008

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Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

(L2)

MER 312: Dynamics and Kinematics

TODAYS AGENDACourse organizationCourse ObjectivesExpectationsResourcesIntroductory MaterialDemonstrations

L1

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Course Organization

Schedule:MWF 11:45 am 12:50 pm NWSE 205 (Lecture)Th. 1:55 pm 4:45 pm NWSE 205 (Lab)

Instructor: Abraham Tchako, Ph.D.Room 235 Steinmetz HallTel.: 388-6144Email: tchakoa@union.edu

Office Hour: MW 10:30 am 11:30 amRoom 235 Steinmetz HallOr by appointment

Textbook: Cleghorn, W. L., Mechanics of Machines, 2005.Oxford University Press

Web Page: http://antipasto.union.edu/~tchakoa/mer312/.

mailto:tchakoa@union.eduhttp://antipasto.union.edu/~tchakoa/mer312/

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

The principal objectives of this course are:

To develop your understanding of the fundamentals of kinematics and dynamics of mechanisms and machine elements.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 basic machine elements such as motors, gears, belts, cam, and common linkages.

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

What is expected of you in this course?

You are expected to:- Attend all classes and design project

sections- Check course web page periodically and

regularly.- Do all homework on time - Do all

progress reports of the design project on time

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

What is expected of you in this course?

You are expected to:- Do all hws, projects and present them

in the form prescribed if any.- Be a good team member (design

project) - Start the project when it is handed out. - ALL your work must be your own or

your groups!

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Course Resources & Webpage

ResourcesTextbook:

W. L. Cleghorn, Mechanics of Machines, Oxford University Press, 2005 with CD-ROM.

Interactive 3D and 2D Virtual models. Flux Player to view virtual models Working Model Cam Design computer program Scaled diagrams of mechanisms for solving problems SolidWorks/COSMOS Motion

Lecture Notes onlineCourse Web page

http://www.engineering.union.edu/~tchakoa/mer312/

http://www.engineering.union.edu/~tchakoa/mer312/

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Course Evaluation

Your Graded will be based on:- Assignments,- 3 Exams (2 exams and 1 final), - Lab/Projects and,- QuizzesArrange yourselves in project groups of 3 to 4 by 9/25If not in a group by that date You will be assigned to one

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Mechanical Engineering

AerodynamicsHydrodynamics

Fluid Mechanics

Thermodynamics

KINETICSKINEMATICS

DynamicsStatics Stress Analysis

Solid Mechanics

Introduction

KINEMATICS -

THE STUDY OF MOTIONWITHOUT REGARD TO FORCES

KINETICS -

THE STUDY OF FORCESDUE TO MOTION

DESIGN -

THE CREATION OF SOMETHINGTHAT DIDN'T EXIST BEFORE

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Units are the Bane of an Engineers Existence

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Definitions

Mechanism: a device which transforms motion to some desirable pattern and typically develops very low forces and transmits little power.

Machine: typically contains mechanisms which are designed to provide significant forces and transmit significant power

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Demonstrations

Single-cylinder piston engine

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Definitions

Similarities: They are both combinations of rigid bodies (Links) the relative motion among the rigid bodies are definite.

Differences: Machines transform energy to do work, while mechanisms do not necessarily perform this function.

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Commonly Employed Mechanisms

Slider Crank Mechanisms:

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Commonly Employed Mechanisms

Four-Bar Mechanisms:

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Commonly Employed Mechanisms

Belt Drive and Gearing Mechanisms:

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Commonly Employed Mechanisms

Cam Mechanisms:

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Kinematic Chains and Kinematic pairs

Kinematic Chain: is an assemblage of links and kinematic pairs capable of relative motion. The base link is not specified.

Mechanism: a kinematic chain in which at least one link is fixed (the base/ground link) with the purpose of transforming motion.

Kinematic Pairs or Joints: connect the links of the mechanism together.

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Links

Link is a rigid body that possesses at least 2 nodes.

Node is an attachment point to other links via joints.

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Kinematic Pairs or Joints

Kinematic pair/ joint is a connection between two or more links at their nodes. It allows motion to occur between the links.

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Basic Types of Kinematic Pairs or Joints

Turning pair/Pivot is a joint that allows relative turning/rotary motion between two links.

Slider or sliding pair is a joint that allows relative sliding/linear motion between two links.

Rolling pair allows relative rolling motion between two links.

A connection may allow more than one type of relative motions between its links.

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Sample of Kinematics Pairs

Prismatic

Revolute

Screw

1 DOF

Joints

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Sample of Kinematics Pairs

Cylindrical Pin-in-slot

Half joint

2 DOF Joints

Multi-link

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Sample of Kinematics Pairs

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Joints restraint and allow motion between links

Sample of Kinematics Pairs

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Sample Problems for self study

Problem for self study

Identify

(1) Number Elements(2) Number Joints(3) Calculate mobility

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Demonstrations

Single-cylinder piston engine

Union CollegeMechanical Engineering

MER 312: Dynamics and Kinematics (of Mechanisms) / AT

Demonstrations

Upload Mechanism

MER 312: Dynamics and KinematicsCourse OrganizationThe principal objectives of this course are:What is expected of you in this course?What is expected of you in this course?Course Resources & WebpageCourse EvaluationUnits are the Bane of an Engineers ExistenceDefinitionsDemonstrationsDefinitionsLinksDemonstrationsDemonstrations