D'ALEMBERT PRINCIPLE by Amira Surfeena https://padlet.com/amirasurfeenam/5ed76pk5g0y5 FORCE ANALYSIS OF LINKAGES BY ENERGY METHOD en-us 2017-10-29 13:18:56 UTC 2025-10-04 15:08:17 UTC hello@padlet.com MME 3106 VIBRATION OF MACHINES amirasurfeenam https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201489111 TOPIC 2: D’ Alembert Principle, Force Analysis of Linkages By Energy Method

LECTURER:
DR AFIFAH BT MOHD ALI

GROUP MEMBERS: 
AISYAH MADIHAH BT MUSTAFA  (1526748)
AMIRA SURFEENA BT MANSUR (1320400)
NOOR AFIFAH INSYIRAH BT MOHD GHANI (1320944)
NUR SHAFIHA BT JUHARI (1326100)
SITI NABIHAH BT MOHAMAD ROZY (1322378)
SITI NUR AININA BT MAHAZIS (1329022)
ZAIDATUN AMINAH BT ZAINUDDIN (1328400)
]]> 2017-10-29 13:22:33 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201489111 INTRODUCTION OF ENERGY METHOD amirasurfeenam https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201489199 Two basic approaches:

1. Application of Newton’s laws of motion to free-body diagrams.

2. Use of work.

FIRST APPROACHES

-Deal with vector quantities. E.g. force, displacement.

-Need to resolve in 2D or 3D.

-Need to introduce all internal forces on free-body diagrams.

LINK
First approaches
]]> 2017-10-29 13:23:47 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201489199 Second approaches amirasurfeenam https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201489379 -Deal with scalar quantities. E.g. work.

Advantages of Work (Energy Method)
-Avoid of computing the acceleration.

-Lead to velocity changes as function of forces which do work.

-Work energy equation involves only forces which do work.

-Give rise to changes in magnitude of velocities.

LINK
Second approaches]]> 2017-10-29 13:26:43 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201489379 Concept of D'alembert : afifahinsyirah https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201493958 Static Force Analysis :
Graphical and analytical methods of force analysis on stationary mechanisms
  - Equilibrium method
  - Virtual (Energy) method

Dynamic Force Analysis :
Force analysis of mechanisms in motion
  - D’ALembert’s principle OR
  - Newton’s 2nd Law of motion

D' Alembert's principle is summarized as follows: 
1. The vector sum of all external forces and inertia forces acting upon a system of rigid bodies is zero. 

2. The vector sum of all external moments and inertia torques acting upon a system of rigid bodies is also separately zero.
]]> 2017-10-29 14:23:20 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201493958 D'alembert's equation : afifahinsyirah https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201494001 According to Newton’s second law of motion :

For Linear Motion :
1. Static case : ∑F =  0 
2. Dynamic case : ∑F = m.a

where : F = resultant force acting on the body 
             m = mass of the body 
              a = Linear mass of the acceleration of the body
For Rotational Motion :
1. Static case : ∑M = 0 
2. Dynamic case ∑M = Iα
For D'alembert's Principle :
1. Static case : ∑F - ma = 0 
2. Dynamic case : ∑M - Iα = 0

where :  ∑M = sum of any external moment 
                   α = angular acceleration
]]> 2017-10-29 14:23:51 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201494001 maddiymae27 https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201495765 2017-10-29 14:42:21 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201495765 maddiymae27 https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201495835 2017-10-29 14:43:13 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201495835 maddiymae27 https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201497895 2017-10-29 15:04:06 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201497895 maddiymae27 https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201497952 2017-10-29 15:04:39 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201497952 maddiymae27 https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201498035 2017-10-29 15:05:41 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201498035 Mass / Spring System shafihajuhari94 https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201501795 Using the concept of virtual displacements, and virtual work, we can derive the equations of motion of lumped parameter systems.

Number of degree of freedom =1
Coordinate to describe the motion is x
No external force (only initial displacement condition)

Formulation using Newton's Law:
F = ma
F-ma=0 (consider m.a to be inertial force)
D’Alembert’s law
F=0
Appears when:
- external force tries to accelerate a body with mass
- direction of inertial force always opposite to the define position direction of body mass position

m (kg) : mass
k (N/m) : spring constant
c (Ns/m) : damping coefficient
F (N) : external force
x (m) : displacement of body]]> 2017-10-29 15:44:06 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201501795 General one degree of freedom system shafihajuhari94 https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201501821 Fi : inertial force (mass)
Fe : elastic force (spring)
Fd : damping (viscous friction)

Fe = kx
Fi = ma = m.dv/dt = m. d^2x/dt^2
Fd = cv = c.dx/dv
F-Fe-Fd-Fi=0
Thus, the equation of motion is:
F - kx - m. d^2x/dt^2 - c.dx/dv]]> 2017-10-29 15:44:26 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201501821 PRINCIPLE OF VIRTUAL WORK zaidatunaminah https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201502148 The work done by all the forces acting on a system, during a small virtual displacement is ZERO.

A virtual displacement is a small displacement of the system which is compatible with the geometric constraints.

A geometric constraint is a limitation placed on an object, which can have two dimensions or more, because there are zero degrees of freedom


Method of Virtual Work is suitable for analysis of multi-link structures (pin-jointed members) which change configuration.

it is most suited for solving equilibrium problems involving a syste of several connected rigid bodies.
]]> 2017-10-29 15:47:49 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201502148 nabihahrozy https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509051 2017-10-29 16:53:59 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509051 nabihahrozy https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509227 2017-10-29 16:55:32 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509227 nabihahrozy https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509274 2017-10-29 16:56:13 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509274 nabihahrozy https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509388 2017-10-29 16:57:01 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509388 nabihahrozy https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509458 2017-10-29 16:57:43 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509458 nabihahrozy https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509617 2017-10-29 16:59:26 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201509617 7. D’Alembert’s Principle & Energy Method nabihahrozy https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201511049 Solving the example for D'Alembert's Principle & Energy Method ]]> 2017-10-29 17:13:42 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201511049 Example aininamahazis https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201523261 Determine the force P]]> 2017-10-29 18:59:22 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201523261 aininamahazis https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201547033 2017-10-29 22:38:36 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201547033 Work done zaidatunaminah https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201565540 2017-10-30 01:16:37 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201565540 zaidatunaminah https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201569716 2017-10-30 01:41:58 UTC https://padlet.com/amirasurfeenam/5ed76pk5g0y5/wish/201569716