應用力學應用力學 ((二二 ))DynamicsDynamics

朱銘祥教授朱銘祥教授

Instructor:Instructor: Prof. Ming-Shaung Ju ( Prof. Ming-Shaung Ju ( 朱銘祥教朱銘祥教授授 ) (ME Building 7th F Room 727, ext 62163)) (ME Building 7th F Room 727, ext 62163)

Office hours: Thursday 2PM, Friday 2PMOffice hours: Thursday 2PM, Friday 2PM Teaching Assistant:Teaching Assistant: 黃繪禎 助教 黃繪禎 助教 (ME Buildin(ME Buildin

g 12th F Room C11, ext 62263)g 12th F Room C11, ext 62263) Textbook:Textbook: R. C. Hibbeler, R. C. Hibbeler, Engineering MechEngineering Mech

anics: Dynamicsanics: Dynamics, 12th Ed., 2009., 12th Ed., 2009. Reference:Reference: J.L. Meriam, Engineering Mechan J.L. Meriam, Engineering Mechan

ics: Dynamics, 6th Ed., 2008.ics: Dynamics, 6th Ed., 2008.

What is Dynamics?What is Dynamics?Branch of mechanics which deals with the Branch of mechanics which deals with the

motion of bodies under the action of forcesmotion of bodies under the action of forces

MechanicsMechanics Statics – effects of forces on bodies at restStatics – effects of forces on bodies at rest DynamicsDynamics

Kinematics – study of motion of bodies without Kinematics – study of motion of bodies without reference to forces which cause the motionreference to forces which cause the motion

Kinetics – relates action of forces on bodies to tKinetics – relates action of forces on bodies to their resulting motionheir resulting motion

History of DynamicsHistory of Dynamics

Galileo Galilei, 1564-1642 Issac Newton, 1642-1727 Leonhard Euler, 1707-1783 Joseph L. Lagrange, 1736-1813

Applications of DynamicsApplications of Dynamics Modern machines and structures Modern machines and structures

operated with high speed operated with high speed ((accelerationacceleration))

AnalysisAnalysis & & designdesign of of Moving structureMoving structure Fixed structure subject to shock loadFixed structure subject to shock load Robotic devicesRobotic devices Automatic control systemAutomatic control system Rocket, missiles, spacecraftRocket, missiles, spacecraft Ground & air transportation vehiclesGround & air transportation vehicles MachineryMachinery Human movementHuman movement

ProceduresProcedures1.1. Read the problem & correlate Read the problem & correlate actualactual

physicalphysical situationsituation with with theorytheory2.2. Draw any Draw any necessarynecessary diagramdiagram (e.g. (e.g. free-free-

bodybody) & tabulate problem data) & tabulate problem data3.3. Establish a Establish a coordinatecoordinate systemsystem

((reference framereference frame) & apply relevant ) & apply relevant principlesprinciples ( (mathematicalmathematical form) form)

4.4. Solve necessary Solve necessary equationsequations algebraicallyalgebraically then use a consistent set of then use a consistent set of unitsunits & & complete the solutioncomplete the solution

5.5. Study the Study the answeranswer using technical using technical judgmentjudgment & common sense & common sense

6.6. Review the problem.Review the problem.

Example: pendulumExample: pendulum

OutlineOutline

2/20 Introduction & Kinematics of a 2/20 Introduction & Kinematics of a particleparticle

3/7 Kinetics of a particle: Force and 3/7 Kinetics of a particle: Force and AccelerationAcceleration

3/14 Kinetics of a particle: Work and 3/14 Kinetics of a particle: Work and EnergyEnergy

3/26 Kinetics of a particle: Impulse and 3/26 Kinetics of a particle: Impulse and MomentumMomentum

4/9 Planar kinematics of a Rigid Body4/9 Planar kinematics of a Rigid Body

4/23 Planar kinetics of a Rigid Body: 4/23 Planar kinetics of a Rigid Body: Force and AccelerationForce and Acceleration

Outline (cont’d)Outline (cont’d)

5/7 Planar kinetics of a Rigid Body: Work and 5/7 Planar kinetics of a Rigid Body: Work and EnergyEnergy

5/16 Planar kinetics of a Rigid Body: Impulse a5/16 Planar kinetics of a Rigid Body: Impulse and Momentumnd Momentum

5/28 Three-Dimensional Kinematics of a Rigid 5/28 Three-Dimensional Kinematics of a Rigid Body & Overview of 3D Kinetics of a Rigid BoBody & Overview of 3D Kinetics of a Rigid Bodydy

6/13 Vibrations: under-damped free vibration, 6/13 Vibrations: under-damped free vibration, energy method, undamped forced vibration, energy method, undamped forced vibration, viscous damped vibrations viscous damped vibrations

GradingGrading

Quiz and Homework 20% Quiz and Homework 20% 1st Midterm 25%1st Midterm 25% 2nd Midterm 25%2nd Midterm 25% Final Exam 35%Final Exam 35%

Total = 105% ??Total = 105% ??

Notes:Notes:

Suggest to take lecture notes!Suggest to take lecture notes! HomeworkHomework be assigned on a be assigned on a weeklyweekly ba ba

sis, a sis, a quizquiz after a Chapter is finished after a Chapter is finished Homework should be Homework should be hand-writtenhand-written Solutions to homework problem set wiSolutions to homework problem set wi

ll also be post at FTP (140.116.155.72ll also be post at FTP (140.116.155.72 ；；PortPort ：： 2121 ；； user: student, password: suser: student, password: student)tudent)