Exploring the Differences between τxy and τyx in the Cauchy Stress Tensor

In summary: Do you have any notes or online notes that explain further on this part? I have tried to search online , but no avail..Homework Equations
  • #1
chetzread
801
1

Homework Statement


https://en.wikipedia.org/wiki/Cauchy_stress_tensor[/B]
I don't understand the difference between τxy . τyx , τxz , τzx , τyz , τzy ..What did they mean ?

Homework Equations

The Attempt at a Solution


taking τxy and τyx as example , what are the difference between them ? They are the same , right ? they mean the shear force shear the xy plane , right ?
 
Physics news on Phys.org
  • #2
chetzread said:

Homework Statement


https://en.wikipedia.org/wiki/Cauchy_stress_tensor[/B]
I don't understand the difference between τxy . τyx , τxz , τzx , τyz , τzy ..What did they mean ?

Homework Equations

The Attempt at a Solution


taking τxy and τyx as example , what are the difference between them ? They are the same , right ? they mean the shear force shear the xy plane , right ?
##\tau_{xy}## represents the shear stress in the x direction on a plane of constant y. ##\tau_{yx}## represents the shear stress in the y direction on a plane of constant x.
 
  • Like
Likes mohamedibr752 and chetzread
  • #3
Chestermiller said:
##\tau_{xy}## represents the shear stress in the x direction on a plane of constant y. ##\tau_{yx}## represents the shear stress in the y direction on a plane of constant x.
ok , one more question , why we need to consider the forces acting on 3 surfaces only ? There are 6 face for cubic , right ?
 
  • #4
chetzread said:
ok , one more question , why we need to consider the forces acting on 3 surfaces only ? There are 6 face for cubic , right ?
You can get the forces on all 6 faces of the cube using the Cauchy stress relationship, and taking into account the possibility that the stress tensor may be varying with spatial location.
 
  • Like
Likes chetzread
  • #5
Chestermiller said:
You can get the forces on all 6 faces of the cube using the Cauchy stress relationship, and taking into account the possibility that the stress tensor may be varying with spatial location.
so , in this case , the author in wikipedia only consider 3 surface ? Which is accepatble , too ?
 
  • #6
Chestermiller said:
##\tau_{xy}## represents the shear stress in the x direction on a plane of constant y. ##\tau_{yx}## represents the shear stress in the y direction on a plane of constant x.
i think you mean ##\tau_{yx}## represents the shear stress in the x direction on a plane of constant y and vice versa ? because the force σyx (τyx) is in the x direction at constant y ...?
 
  • #7
chetzread said:
i think you mean ##\tau_{yx}## represents the shear stress in the x direction on a plane of constant y and vice versa ?
I don't know. I always get the two confused. And it doesn't matter anyway because the stress tensor is symmetric.
 
  • #8
Chestermiller said:
I don't know. I always get the two confused. And it doesn't matter anyway because the stress tensor is symmetric.
continue from post #6 ,
because the force σyx (τyx) is in the x direction at constant y ...?
 
  • #9
chetzread said:
because the force σyx (τyx) is in the x direction at constant y ...?
They usually "prove" this using a balance of moments.
 
  • #10
chetzread said:
so , in this case , the author in wikipedia only consider 3 surface ? Which is accepatble , too ?
It looks to me like the guy in wiki is correct for the three surfaces he considered.
 
  • Like
Likes chetzread
  • #11
Chestermiller said:
It looks to me like the guy in wiki is correct for the three surfaces he considered.
If we consider 6 surface, then it's wrong?
 
  • #12
Chestermiller said:
They usually "prove" this using a balance of moments.
What do you mean? I m getting more confused now...
 
  • #13
chetzread said:
What do you mean? I m getting more confused now...
Look up in the literature or on Google how it is shown that the stress tensor is symmetric.
 
Last edited:
  • #14
Chestermiller said:
Look up in the literature or on Google how it is shown that the stress tensor is symmetric.
OK, is my idea in post #6 correct?
 
  • #15
chetzread said:
OK, is my idea in post #6 correct?
It really doesn't matter if the stress tensor is symmetric.
 
  • Like
Likes chetzread
  • #16
Chestermiller said:
It really doesn't matter if the stress tensor is symmetric.
So, both my post and your post could be correct?
 
  • #17
Sorry, I have another notes here... I couldn't understand why the (tau)_xy could be = (tau)_yx? Why should they be the same?
 

Attachments

  • IMG_20160907_225729.jpg
    IMG_20160907_225729.jpg
    23.3 KB · Views: 511
  • #18
chetzread said:
Sorry, I have another notes here... I couldn't understand why the (tau)_xy could be = (tau)_yx? Why should they be the same?
I recommended references that contain the same kind of derivation that is in virtually every textbook. And I already alluded to a balance of moments. The rest is up to you to work out.
 
  • #19
Chestermiller said:
I recommended references that contain the same kind of derivation that is in virtually every textbook. And I already alluded to a balance of moments. The rest is up to you to work out.
Do you have any notes or online notes that explain further on this part? I have tried to search online , but no avail..
 

Related to Exploring the Differences between τxy and τyx in the Cauchy Stress Tensor

What is a Cauchy stress tensor?

A Cauchy stress tensor is a mathematical representation of the stress state at a specific point in a continuous medium, such as a solid or fluid. It is a second-order tensor that describes the magnitude and direction of the stress acting on a given surface at that point.

How is a Cauchy stress tensor calculated?

A Cauchy stress tensor is calculated by taking the derivative of the force vector with respect to the area vector on an infinitesimal surface element in the material. This is represented mathematically as the gradient of the stress tensor.

What does a Cauchy stress tensor tell us about a material?

A Cauchy stress tensor provides information about the internal forces and stresses within a material, including both normal and shear stresses. It can also provide insight into the deformation and behavior of the material under different loading conditions.

What is the significance of the Cauchy stress tensor in mechanics?

The Cauchy stress tensor is a fundamental concept in mechanics, as it allows for the analysis and prediction of the behavior of continuous materials under different types of loading. It is used in numerous fields, including solid mechanics, fluid mechanics, and structural engineering.

What are some common applications of the Cauchy stress tensor?

The Cauchy stress tensor has numerous applications in various fields, including stress analysis of structures, design of mechanical components, prediction of material failure, and simulation of fluid flow. It is also used in the development of mathematical models and simulations in materials science and engineering.

Similar threads

  • Special and General Relativity
Replies
3
Views
1K
  • Advanced Physics Homework Help
Replies
4
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
2K
  • Mechanical Engineering
Replies
12
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
7
Views
2K
Replies
18
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
3K
  • Engineering and Comp Sci Homework Help
Replies
6
Views
1K
Back
Top