Misinterpretation of Mohr's Circle Rotation Formula?

In summary, the author is trying to solve a homework equation using the Mohr circle and they are having trouble finding the mistake. They also mention that they have used sin2(-θ) and cos2(-θ), but they still can't find the answer.
  • #1
chetzread
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1

Homework Statement


for the τx'y' , i use the formula of -0.5(σx - σy)sin2θ + τxycos2θ , i found the ans is -41.3 rather than positive 41.3 , which part of my working is wrong? or I misunderstood something?

Homework Equations

The Attempt at a Solution

 

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  • #2
here's the formula:
 

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  • #3
after checking many times, I still couldn't find out the mistake
 
  • #4
anyone can help ?
 
  • #6
bump
 
  • #7
or it's wrong to use the transformation equation to do this question?
 
  • #8
Unfortunately, it seems that you are not getting a response at the moment.

Have you looked at the "similar" threads listed at the foot of this page, to see whether something similar may have previously been discussed? Sometimes one can be lucky!
 
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  • #9
NascentOxygen said:
Unfortunately, it seems that you are not getting a response at the moment.

Have you looked at the "similar" threads listed at the foot of this page, to see whether something similar may have previously been discussed? Sometimes one can be lucky!
Which thread?
 
  • #10
chetzread said:
Which thread?
You don't see links to some past threads when
you scroll way down below here [emoji652]
 
  • #11
NascentOxygen said:
You don't see links to some past threads
way down here [emoji652]
no, i don't think i can find the answer for this question in other thread,can you help?
 
  • #12
I have also used sin2(-θ) and cos2(-θ) instead of sin2(θ) and cos2(θ), but i still couldn't find the answer same as the author , which part of my working goes wrong
?
 
  • #13
chetzread said:
can you help?
The topic is one I know nothing about, I'm sorry.
 
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  • #14
NascentOxygen said:
The topic is one I know nothing about, I'm sorry.
ok , anyone else can help ?
 
  • #15
bump
 

FAQ: Misinterpretation of Mohr's Circle Rotation Formula?

What is the purpose of rotation in Mohr's circle?

The purpose of rotation in Mohr's circle is to determine the principal stresses and their orientations in a given stress state. By rotating the circle, we can visualize the stress state in different orientations and easily identify the maximum and minimum principal stresses.

How is rotation achieved in Mohr's circle?

Rotation in Mohr's circle is achieved by drawing a line from the center of the circle to the desired angle of rotation. This line represents the new orientation of the stress state. The radius of the circle remains constant, but the angle changes.

What is the significance of the angle of rotation in Mohr's circle?

The angle of rotation in Mohr's circle represents the orientation of the stress state with respect to the reference axis. It is used to determine the direction of the principal stresses and the plane on which they act.

Can rotation in Mohr's circle be used for any type of stress state?

Yes, rotation in Mohr's circle can be used for any type of stress state, including both two-dimensional and three-dimensional stress states. It is a useful tool for visualizing and analyzing complex stress states.

How does rotation affect the position of the stress state on Mohr's circle?

Rotation does not affect the position of the stress state on Mohr's circle, as the radius remains constant. However, it does change the orientation of the stress state, which can provide valuable information about the principal stresses and their directions.

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