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
Discussion:
42 comments Page 3 of 5.
Akshay said:
8 years ago
I also get Answer is 16/15.
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.
Hollow section is 16T/piD^3*[1-[D^4/d^4]].
The ratio of these to is 15/16 once remembering d=D/2.
MAHARAJ said:
8 years ago
@Bhagchand.
Yes, you are right.
The answer is 16/15.
Yes, you are right.
The answer is 16/15.
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.
So,
Zp(s)/Zp(h)=[π/32d^4]/[π/32*(15d^4)/16],
=16/15.
Krishnavn said:
8 years ago
Here, the answer must be 16/15.
Raghavendra said:
8 years ago
Yeah, the answer must be 16/15.
Shatakshi said:
9 years ago
It's true, ultimately the ratio of Tmax (Solid) / Tmax (Hollow) = D^4/(D^4-d^4).
Let D=20 mm & d=10mm, then D^4=160000 mm^4 & d^4=10000 mm^4.
Therefore, D^4/(D^4-d^4) = 16/15.
Let D=20 mm & d=10mm, then D^4=160000 mm^4 & d^4=10000 mm^4.
Therefore, D^4/(D^4-d^4) = 16/15.
Dwarika prasad sahoo said:
9 years ago
If Solid and Hollow shaft are of the same material and same weight, then Hollow shaft has more strength.
But when outer diameter is same (weight will not be same) then Solid shaft has more strength, so here ratio of the strength of solid and Hollow shaft should be more than 1 as outer diameter same.
But when outer diameter is same (weight will not be same) then Solid shaft has more strength, so here ratio of the strength of solid and Hollow shaft should be more than 1 as outer diameter same.
Raju Katara said:
9 years ago
A hollow steel shaft of 300 mm external diameter and 200 mm internal diameter has to be replaced by a solid steel shaft of 300 mm external diameter and 200 mm internal diameter has to be replaced by a solid steel shaft of?
Give me the answer.
Give me the answer.
(1)
AMIT PANDIT said:
10 years ago
For outer diameter (odd) moment of inertia = d^4.
Inner diameter, moment of inertia = (d/2)^4 = (d^4)/16.
For hollow shaft = d^4-(d^4)/16.
= (15/16)d^4.
So, the ratio of hollow shaft is 15/16.
Inner diameter, moment of inertia = (d/2)^4 = (d^4)/16.
For hollow shaft = d^4-(d^4)/16.
= (15/16)d^4.
So, the ratio of hollow shaft is 15/16.
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