Mechanical Engineering - Strength of Materials - Discussion

Discussion Forum : Strength of Materials - Section 5 (Q.No. 5)
5.
A shaft of diameter D is subjected to a twisting moment (T) and a bending moment (M). If the maximum bending stress is equal to maximum shear stress developed, then M is equal to
T/2
T
2T
4T
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
11 comments Page 1 of 2.

Hamza said:   4 years ago
@Srilakshmi.

How MZp=TZs?

Humayoun said:   4 years ago
For maximum bending and shear stress M=T/√2.
For simple bending and shear stress M=T/2.

Hardik said:   6 years ago
@Imran right.

Simran said:   7 years ago
I agree with you @Imran.

SRILAKSHMI said:   8 years ago
Bending stress= shear stress.

MY/I=TR/J
Now cross multiply
MYJ=TRI
Now MZp=TZs
M(π*D^3/16)=T(π*D^3/32)
M=T(π*D^3/32)/(π*D^3/16)
M=T/2.
(2)

Shiva said:   8 years ago
@Sandeep.

in last step J=2I;
M=(I/2I)*T;;
M=T/2.

Siva Kumar G said:   9 years ago
@Sandeep.

Calculate well from the last second step. You will get T/2.

Sandeep said:   9 years ago
I=((φ)*(D^4))/64 and,
J=((φ)*(D^4))/32, for a circle.
NOW,
Bending moment = Shear stress.
or, (M/I) * y = (T/J) * r.
or, M = (I/J) * T * (r/y) [since, r=Ymax]
or, M = (I/J) * T.
so, M = 2 T.

Imran said:   9 years ago
@Gaurav, Thanks for your answer.

But I think that answer is for simple bending and shear stress not for Max bending and shear stresses.

Boss said:   9 years ago
The answer is 2T.


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