Kutzbach Criteria And Grubler’s criteria with suitable example and introduction to basic terms

1. KUTZBACH CRITERIA
AND
GRUBLER’S CRITERIA
By: www.mechaholic.in

2. Degree Of Freedom in 3D

Degree of Freedom (DOF) of a body is defined
as number of independ movement the body has

A body in 3D has 6 Degree of Freesom

3 Rotational

3 Translational

3. Degree Of Freedom in 2D (Planar)

A body in 2D has 3 Degree of Freesom

1 Rotational

2 Translational

4. Basic Term

5. Links
●
Link is a member or combination of member
connecting each other and has relative motion
between each other

6. Kinematic Pair
Lower Pair
It is a pair of link which have surface to surface or
area contact between members.
Eg: Nut and Screw Assembly, Slider and Slotted
Link

7. ●
Higher Pair
●
If a pair has point or line contact between links
or member
●
Eg:
Cam And Follower
Ball Bearing

8. KUTZBACH CRITERIA

Kutzbach Criteria is for determining Degree of
Freedom of body in Planar Mechanism ( 2D)

Here:

L = Number of Link

J = Number Of Lower Pair

H = Number Of Higher Pair

9. Example

11. 
Formula is DOF = 3 (L-1) – 2 J – H

DOF = 3 (7-1) – 2 (8) – (1)
Therefore
DOF = 1

12. GRUBLER’S CRITERIA

When Higher Pair (H) = 0 in Kutzbach Criteria
then the Equation procured is Grubler's Criteria

Here:

L = Number of Link

J = Number Of Lower Pair

13. Example

15. Formula is DOF = 3 (L-1) – 2 J
DOF = 3 (8-1) – 2 (10)
Therefore
DOF = 1

16. Thank You
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