KUTZBACH CRITERIA AND GRUBLERS CRITERIA
KUTZBACH CRITERIA
AND
GRUBLERS CRITERIA
By: www.mechaholic.in
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
Degree Of Freedom in 2D (Planar)
A body in 2D has 3 Degree of Freesom
1 Rotational
2 Translational
Basic Term
Links
Link is a member or combination of member connecting each other and has relative motion between each other
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
Higher Pair
If a pair has point or line contact between links or member
Eg: Cam And Follower Ball Bearing
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
Example
Formula is DOF = 3 (L-1) 2 J H
DOF = 3 (7-1) 2 (8) (1)
Therefore DOF = 1
GRUBLERS 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
Example
Formula is DOF = 3 (L-1) 2 J
DOF = 3 (8-1) 2 (10)Therefore DOF = 1
Thank You
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