Showing posts with label truss numericals. Show all posts
Showing posts with label truss numericals. Show all posts

Saturday 3 December 2011

SOLUTION OF EME-102; TRUSS ANALYSIS

SOLVE THE TRUSS GIVEN BELLOW WITH THE HELP OF METHODS OF JOINT





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a)      REPLACE JOINTS WITH REACTIONS at A and at B
              



       
b)      Draw FBD of the TRUSS

 
Applying the conditions of Equilibrium of Coplanar Non-concurrent Force System,

 
FX = 0;        Rb – Rah = 0  ------ (i)
(-) ← ● → (+)
FY = 0;        Rav – 10 – 5 – 15 = 0 => Rav = 30 kN ----- (ii)

MA = 0;       10 x 4 + 5 x 4 + 15 x 2 – Rb x 3 = 0  ----- (iii)
                        Rb = 30 kN
                        Hence Rah = Rb = 30 kN

Calculation of Angle θ



The angle θ = tan-1(3/2) = 56.3°



All the unknown forces will be taken as Tensile, if their magnitudes is found negative, then they will be treated as compressive forces.

First we shall choose a joint having only two unknown forces, either we shall choose joint D or joint A
Let us choose joint D first.
We shall consider point D first, as it has only two unknown force. FBD of the point D is drawn.

FX = 0;      F2 = 0
∑ FY = 0;      F1 – 5 = 0
                      F1 = 5 kN



 
Our next joint will be point E. FBD of the joint E is drawn. As F1 = 5 kN, hence unknown forces are two. F3 and F4

FX = 0;     F3 – F4 cos 56.3° = 0
∑ FY = 0;     – F1 – 10 –  F4 sin 56.3° = 0  [ as F1 = 5 kN]
                           F4 = –15/ sin 56.3° = – 18.02 kN
                    F3 = – F4 cos 56.3° = 10 kN


 
Our next joint is C
 F5 and F9 are unknown where as F4 = – 18.02 kN
 F2 = 0
 ∑ FX = 0;     F9 + F4 cos 56.3° = 0
            F9 = F4 cos 56.3° = 10 kN
 ∑ FY = 0;     F5 + F4 sin 56.3° – 15 = 0
                            F5 = – F4 sin 56.3° + 15 = 30 kN
 
F3 = 10 kN;   F5 = 30 kN
        ∑ FX = 0;     F3 = F6 + F7 cos 56.3°
        ∑ FY = 0;     – F5 – F7 sin 56.3° =0
       F7 = – F5/ sin 56.3° = – 36.05 kN

F6 = F3 – F7 cos 56.3° = 10 + 20 = 30 kN


Rav = 30 kN;  Rah = 30 kN

  FX = 0;      F6  = Rah = 30 kN
 ∑ FY = 0;     F8 = Rav = 30 kN


Sl no
Link
Force
Magnitude
Nature
01
ED
F1
 5 kN
 T
02

CD
F2
 0

03

FE
F3
 10 kN
 T
04

CE
F4
 18.02 kN
 C
05

FC
F5
 30 kN
 T
06

AF
F6
30 kN
 T
07

BF
F7
 36.05 kN
 C
08

AB
F8
 30 kN
 T
09

BC
F9
 10 kN
 T


Monday 28 November 2011

QUESTION BANKS: Analyse the following Trusses:

 Analyse the following Trusses:

(1)      A cantilever truss has been as shown in the figure. Find the value of W which will produces a force of magnitudes 15 kN  in the member AB.







(2)        A cantilever truss is loaded as shown in the figure. Find the nature and magnitudes of the forces in each link.





(3)      A cantilever truss has been as shown in the figure. Find the value of W which will produces a force of magnitudes 15 kN  in the member AB.









(4)      A truss has been loaded as shown in the figure. Find the nature and the magnitudes of the forces in the links BC, CH and GH by the methods of sections.







(5) A truss has been loaded as shown in the figure. Find the internal forces in each of the beam.









(6)      A truss has been loaded as shown in the figure. Find the forces in each member and tabulate them by any methods.




compiled by Subhankar Karmakar

more content: click the following links for more questions.

THEORETICAL QUESTIONS ON SIMPLE TRUSSES part-3

QUESTION BANK : ENGINEERING MECHANICS PART-2

QUESTION BANK : ENGINEERING MECHANICS

 

THEORETICAL QUESTIONS ON SIMPLE TRUSSES

SHORT QUESTIONS: TOPIC - TRUSS ANALYSIS

1)      What is a truss? Classify them with proper diagrams.
2)      State the differences between a perfect truss and an imperfect truss.
3)      Distinguish between a deficient truss and a redundant truss.
4)      Write the Maxwell’s Truss Equation.
5)      What are the assumptions made, while finding out the forces in the various members of a truss?
6)      What are the differences between a simply supported truss and a cantilever truss? Discuss the method of finding out reactions in both the cases.


Analyse the following Trusses:
 
(1)      Analyse the Truss by the method of Joints.
(2) Find the internal forces on the links 1, 2 and 3 by the method of Sections.
(3) Determine the magnitude and the nature of the forces in the members BC, GC and GF of the given truss.
(4)   A truss of span 10 m is loaded as shown in the figure. Find the forces in all the links by any method.






compiled by Subhankar Karmakar