The degree of static indeterminacy NS and the degree of kinematic indeterminacy, NK for the plane frame as shown neglecting axial deformation are given by
The degree of static indeterminacy NS and the degree of kinematic indeterminacy, NK for the plane frame as shown neglecting axial deformation are given by Correct Answer N<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em;font-size:10.5px;">S</span> = 4, N<span style="position: relative; line-height: 0; vertical-align: baseline; bottom: -0.25em;font-size:10.5px;">K </span>= 6
Concepts:
The kinematic indeterminacy is given as
Dk = 3j-r-m
j = no of joints
r = no of support reactions
m = no of axially rigid members
Degree of Static Indeterminacy (Ds):
Ds = 3×C – R
C = No of cuts required to make stable cantilever frame
R= No of releases
Calculations:
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Kinematic Indeterminacy:
No of Joints, j = 6
No of support reactions, r = 7 ( 3 at support A, 2 at each support D and F)
No fo axially rigid members, m = 5
Dk = 3j-r-m
Dk = 3 × 6 – 7 – 5
∴ Dk = 6
Static Indeterminacy
No of cuts = 2
Releases
Moment releases at joint D = 1
Moment releases at joint F = 1
Total Releases, R = 2
Dsi = 3 × 2 – 2 = 4
Static Indeterminacy, Ds = 4