Mechanical Engineering - Strength of Materials - Discussion

Discussion Forum : Strength of Materials - Section 1 (Q.No. 10)
The stress induced in a body, when suddenly loaded, is __________ the stress induced when the same load is applied gradually.
equal to
four times
Answer: Option
No answer description is available. Let's discuss.
25 comments Page 2 of 3.

AMOL MORE said:   8 years ago
When the load applied gradually then stress induce = W/A.

When the load applied suddenly then stress induce = 2 * W/A.

By comparing.

(stress) suddenly = 2 * (stress) gradually.

Himanshu Sharma said:   8 years ago
Can anyone please explain how it can be twice?

Mani deepak said:   8 years ago
As in gradually applied load, load varies from 0 to a.

The net load applied is w1 = w/2.

So, the stress is p = w/(2a).

For suddenly applied load stress p1 = w/a.

p1/p = 2, p1 = 2p.

So, stress due to suddenly applied is twice of gradually applied load.

Shivanjal mehra said:   8 years ago
No specific solution is available for this question.

Nemish said:   9 years ago
σ impact load = (F/A)[1+(1+2hAE/F)^0.5].

Krishna said:   9 years ago
Stress do not depend on rate of application of force I prefer equal in both the cases.

Rishi said:   9 years ago

How can you say that the average load is w/2?

In case w is split into 4 loads (w1+w2+w3+w4) applied gradually then average would come w/4.

In this case answer would come 4 times. Your method is completely wrong.

Sanjay said:   1 decade ago
Because new load is P=P1+P2, where P1=P2 so the stress is twice.

AMAN said:   1 decade ago
When we loaded suddenly load 'w' then we consider 'w' load in stress while we loaded gradually load "w' then we consider average value of 'w' which will be w/2 in the stress calculation.

So we know that,
Stress = load/area.

So let p1 is stress when suddenly load and p2 is stress when load is gradually.

So p1 = w/area.

And p2 = (w/2)/area.

So p1/p2 = [w/aria]/[ (w/2) /aria].

So p1/p2 = 2.

p1 = 2p2.

Thats proves that suddenly loaded stress is double to the gradually loaded stress.

Ashu said:   1 decade ago
Ya. As per the formula. Suddenly applied load doubled than gradully applied load.

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