Civil Engineering - Strength of Materials - Discussion

Discussion Forum : Strength of Materials - Section 1 (Q.No. 3)
3.
The ratio of strengths of solid to hollow shafts, both having outside diameter D and hollow having inside diameter D/2, in torsion, is
1/4
1/2
1/16
15/16
3/8
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
42 comments Page 2 of 5.

Maggie said:   1 decade ago
The strength of a solid shaft in torsion is given by,

T(solid shaft) = (pi/16)*(max stres)*(D^3).

T(hollow shaft) = (pi/16)*(max stres)*(D^4-d^4)/D.

On solving we get 15/16.

Ravikumar said:   8 years ago
The solid section max shear stress is 16T/pi D3.
Hollow section is 16T/piD^3*[1-[D^4/d^4]].
The ratio of these to is 15/16 once remembering d=D/2.

Ekon said:   7 years ago
Answer should be 16/15. If the answer is 15/16 then it is implying that the hollow shaft is stronger than the solid shaft of same outer diameter, which is not correct.

Virendra said:   1 decade ago
Ratio will be 16/15.

Simply if equal outer diameter then solid shaft will be more strong. But if material are same then hollow shaft will be more strong.

Murli meena said:   1 decade ago
Dia of solid shaft = D.
DIA OF HOLLOW SHAFT = d/2.

The ratio of solid shaft = 16.
The ratio of hollow shaft = 15.

Total tension in shafts = 15/16.

ABDUL SOVAN KHAN said:   8 years ago
((π/16)*maximum shere stress*(outside dia)^3)/((π/16)*maximum shere stress*((out side dia^4-inside dia^4)/inside dia)=16D^4/15D^4=16/15.

Parth said:   5 years ago
@All.

The question is ratio of the solid shaft to the hollow shaft not hollow shaft to solid shaft.

So the answer will be : 16/15.
(3)

Vamsiambati said:   4 years ago
(T hollow/T shaft)=(D^4-d^4)/D^4.

Here D= Diameter of Solid Shaft.

d=Diameter of Hollow Shaft = D/2.
(D^4-(D/2)^4)/D^4 =15/16.
(8)

Parna sengupta said:   1 decade ago
For a hollow shaft whose external diameter is d and internal diameter is d/2, then what will be the polar modulus?

Bhagchand Golhani said:   8 years ago
Zp= π/32(d^4).
So,
Zp(s)/Zp(h)=[π/32d^4]/[π/32*(15d^4)/16],
=16/15.


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