
Consider the free body diagram of all forces at B.
Q1 = tan -1 Q2 = tan-1 Let the forces developed in the member AB & AC are FAB &FBCrespectively. The force diagram will be as follows at B.
FBC = 942.81 N
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Thus TCD = TDE = 400 N Consider joint C & apply Lami’s theorem Now consider FBD at joint B
By using Lami’s theorem TAB = 230.94 N
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By lami’s theorem
Now consider FBD of sphere A
∑Fx = 0 -RB cos 20 – RQ cos 70 + Rp = 0 -342.02 cos 20 – RQ sin 70 + Rp = 0
∑ fy = 0 RQ sin 70 – 342.02 sin 20 – 1000 = 0
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Consider the free body diagram of joint B as shown in figure
Assume that member BC is in compression & AB is in tension. By using Lami’s theorem at B,
-ve sign indicates that member AB is not in Tension but is in compression. Now, -ve sign indicates that member BC is not in compression but in tension.
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Applying lami’s theorem, we have
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Consider the FBD as shown Applying conditions of equilibrium, ∑fx = 0 RHA – TCD = 0 RHA = TCD ------- (1) ∑fy = 0 RVA – 500 = 0
Taking moment about point A, ∑MA = 0 -(TCD × 5 ) + (500 × 9) = 0 -TCD × 5 = -4500 TCD =
Putting the value in equation (1) RHA = TCD RHA = 900 kN
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EC = 1.61 m Consider triangle AEC
Applying conditions of equilibrium ∑fX = 0 -TBD cos15 + RHA = 0 -------- (1) ∑fy = 0 RVA – 200 – TBD sin15 = 0 RVA – 200 – 0.26TBD = 0 ---------(2) Taking moment at A ∑MA = 0 -(TBD cos15 × 3.2) + (TBD sin15 × 3.84) + (200 × 1.92) = 0 -3.09 TBD + 0.99 TBD + 384 = 0 -2.1 TBD = -384
RVA = 200 + 0.26TBD = 200 + (0.26 × 182.86) RVA = 247.54 N |
Roller support is show in two ways as shown:
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Types of Beam: -
A beam which is just resting on the supports at the end without any connection is known as simply supported beam. It is generally used for vertical landing system.
2. Overhanging Beam –
A beam which is supported at the intermediate point other than ends is called as overhanging beam. Here portion of beam is extended beyond the support
(singly overhanging beam)
b)
(doubly overhanging beam)
3. Cantilever Beam – A beam which is fixed at one end is called as cantilever beam
Here, there are three reactions components:
We can assume any direction for above components. 4. Continuous Beam: A beam having more than two support is called as continuous beam.
5. Compound Beam: When two or more beams are joined together by using internal hinge; or when one beam rests over another beam by using internal roller, then such beam is called as compound beam.
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