1. DYNAMICS OF MACHINES To know the purpose for which the m/c is needed.
To develop concept design.
To analyze the motion involved
- Kinematics
To calculate & analyze the forces and torques required for producing the motion
- Kinetics
To give physical shape to the components.
- Machine Design

2. STATIC FORCE ANALYSIS IN MACHINES
To evaluate the forces acting on the machine members at a particular configuration.
Each configuration is considered as system of rigid bodies in static equilibrium
under the action of external forces.
Helps in finding load carried by each part of the machine during cycle of its operation

3. TYPES OF FORCES Applied forces :
Gas, hydraulic & pneumatic forces etc..
Electrical, magnetic & gravity forces
Constraint forces :
Reaction forces.
Friction forces.
Inertia forces.
Due to mass of accelerating parts

4. Condition for static equilibrium
∑ F i = 0
∑ Mi = 0 F2
M/c part CG F5 F3 F4

5. EQUATIONS FOR STATIC
EQUILIBRIUM
Fi = 0
M i = 0

6. EQUILIBRIUM OF TWO FORCE AND THREE FORCE MEMBERS
Two force member in equilibrium F2 F1

7. THREE FORCE MEMBER IN EQUILIBRIUM

8. O2 A FBDof Link 2 P B P FBDof Link 3 P FBDof Link 4 3 2 4 1 C12 2 F32
STATIC FORCE ANALYSIS IN SLIDER-CRANK MACHANISM A 3 2 4
FBDof
Link 2 O2 P 1 B
C12 2
F32
F34
F12 4 P
F34
F23
FBDof
Link 3
F14 A
F14 P 3
FBDof
Link 4 B
F43

9. STATIC FORCE ANALYSIS IN 4-BAR MECHANISM3 B A
F14 C 4 4 2 P
F14 P P
F34 O2 O4
F43 3
F32 h
C12
F23
F12 O2
C12 = F32 X h

10. O2 P 6 5 C B 3 6 P A 2
F56 C 5 O2 4
F16 1 P
F16 O4
F56

11. F65 5
F45 C O
F54
F54
LINE OF ACTION
OF F34
F14 3
F34
LINE OF ACTION
OF F14 4
F32 A 2
F43 3
C12
F23 O2
F12

12. Inertia force m a
Inertia torque - I α

13. D’ Alemberts principle
In order to find the effect of inertia of the actual link on the forces transmitted to the adjacent links of a mechanism, the actual link may be replaced by a rigid mass-less link to which inertia force F i = -ma is applied. The mass-less link is then under equilibrium under systems of forces along with inertia force.