Mechanical Engineering - Strength of Materials - Discussion

Discussion Forum : Strength of Materials - Section 1 (Q.No. 17)
17.
The maximum diameter of the hole that can be punched from a plate of maximum shear stress 1/4th of its maximum crushing stress of punch, is equal to (where t = Thickness of the plate)
t
2t
4t
8t
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
65 comments Page 1 of 7.

Kalyan gali said:   4 years ago
Shear area = πDT.
Crushing area = πD^2/4,
shear stress= 1/4crushing stress
p/πDT=P/πD^2/4,
D = 4T.
(22)

Vinay said:   5 years ago
D=T should be the correct answer. Analyse the area where crushing force is acting.
(15)

Prudvi Anemoni said:   5 years ago
D=T should be the correct answer. Analyse the area where crushing force is acting.
(7)

Amanullah said:   5 years ago
d=4t is the correct answer

We know that Shearing pull Ps = pie/4* d^2*τ.
Therefore tao(shear stress) = 4Ps/pie d^2.

Same, crushing pull Pc = d*t*σ.
Therefore σ (crushing stress) = Pc/dt.

Now, as per question τ = 1/4 σ.
Solving this, we found d = 16/π *t.

So, dmax = 5.06t its coming, taking nearer value, its 4t.
(5)

Navneet said:   5 years ago
D = t is the correct answer.
(1)

Phani said:   5 years ago
Crushing=4.πd^2.
Shearing=πd.t.
From shearing=1/4.crushing.
d=t.
(2)

Tarik said:   5 years ago
The answer is d=t.

C.Felices said:   6 years ago
The answer is d=t.

Subhendu said:   6 years ago
We know that Shearing pull Ps = pie/4* d^2*tao.
Therefore tao(shear stress) = 4Ps/pie d^2.

Same, crushing pull Pc = d*t*sigma.
Therefore sigma (crushing stress) = Pc/dt.

Now, as per question tao = 1/4 sigma.
Solving this, we found d = 16/pie *t.

So, dmax = 5.06t its coming, taking nearer value, its 4t.
I think this may clear your doubt.

JAYADEB DASH said:   6 years ago
The answer is d = t.

1. Max shear stress in plate = 1/4 max crushing stress in the punch.
2. Shear stress in plate = p/ dt.
3. Crushing stress in punch = 4p/ d^2.
4. Now p/' dt = 4p/4 d^2.

And d = t.
(1)


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