Mechanics of Materials - Shear and Compression

In summary: I found out what the factor is: it is the rule-of-thumb factor that the yield strength of a material is about 1.5 times its tensile strength.In summary, the conversation discusses a homework problem involving checking the strength of an axis for shear and compression. The relevant formulas and symbols are mentioned and a possible solution is presented. The conversation also touches on the difference between shearing strength and compression strength, as well as the relationship between yield strength and tensile strength. The factor of 1.5 is identified as a rule-of-thumb factor for the yield strength of a material.
  • #1
Femme_physics
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  • #2
I do not know what all your symbols mean, but your calculation for the shear stress and tensile strength is correct.

I do see that your relevant formula mentions 0.5/0.6, while you apply 1.5/2.0.
Is that intentional?
TBH, I do not know what this factor is. Do you?
 
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  • #3
Sorry it took me a while to reply, I had a materials strength lab reports to give.

I do see that your relevant formula mentions 0.5/0.6, while you apply 1.5/2.0.
Is that intentional?
TBH, I do not know what this factor is. Do you?

I was hoping you'd tell me that :smile:

Well, so my answer is correct? At any rate, let's interpret the symbols. Ts [N/mm^2] = max shearing strength in the part
Fmax [N] – Max shearing force
As = Area of shearing
[T] = allowable shearing strength
Safe factory

Sigma/c [N/mm^2] – Max compression strength in the part
Fmax = max compression force
A/c = area of the compression
[Sigma/c] [Mpa] – allowable compression strength
safely coeffecient
 
  • #4
How did the material strengths lab report go?


Well, I didn't study material sciences, so there are a few technical aspects that escape me...

What is [itex]d \cdot t_{min}[/itex]?
And your formulas appear to contain [itex]lc[/itex] instead of [itex]/c[/itex]...?
What are [itex][\sigma_t][/itex] and [itex]\sigma_y[/itex]?
What's the difference between shearing strength and compression strength?

I would expect the extra factor to be some type of rule-of-thumb factor, but I have no clue for what...
 
  • #5
How did the material strengths lab report go?

Great! I copied it from the smartest guy in class (specifically said "guy" :wink: ) so it have better turned out great. I just don't like to give out reports as much as I like to solve exercises.

I don't see d x t (min)

As far as Ic instead of /c, I might have miscopied! Not sure whether it's "I" or "/"

Sigma y is "yield strength"
Sigma t is (I think) "tensile strength". There's appearing a relation between that and compression or shearing strength.
What's the difference between shearing strength and compression strength?

pushpull.gif


:smile:
 
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  • #6
Femme_physics said:
Great! I copied it from the smartest guy in class (specifically said "guy" :wink: ) so it have better turned out great. I just don't like to give out reports as much as I like to solve exercises.

I'm certain it would turn out even better if you let the smartest person in class do it! :smile:


Femme_physics said:
I don't see d x t (min)

There it is!
http://img202.imageshack.us/img202/8345/formulas2.jpg


Femme_physics said:
As far as Ic instead of /c, I might have miscopied! Not sure whether it's "I" or "/"

Sigma y is "yield strength"
Sigma t is (I think) "tensile strength". There's appearing a relation between that and compression or shearing strength.

Okay... I'll just accept that for now...


Femme_physics said:
http://jclahr.com/science/earth_science/tabletop/pushpull.gif

:smile:

Aha!
 
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FAQ: Mechanics of Materials - Shear and Compression

What is shear stress and how is it calculated?

Shear stress is the force per unit area that a material experiences when subjected to sideways or parallel forces. It is calculated by dividing the force applied by the cross-sectional area of the material.

What is the difference between shear stress and normal stress?

Shear stress is caused by forces acting in opposite directions parallel to the material, while normal stress is caused by forces acting perpendicular to the material. Shear stress is also calculated as force per unit area, while normal stress is calculated as force per unit area perpendicular to the applied force.

How does shear stress affect the strength of a material?

Shear stress can cause a material to deform or fail, depending on the material's properties and the magnitude of the applied force. Materials with high shear strength are able to withstand larger shear stresses before failing.

What is the difference between compression and tension?

Compression is a type of stress that occurs when forces act to compress or shorten a material. Tension, on the other hand, is a type of stress that occurs when forces act to elongate or stretch a material. Both can cause a material to deform or fail, but in opposite directions.

How is shear stress distributed in different materials?

The distribution of shear stress in a material depends on its shape, size, and the type of force applied. In general, shear stress is highest at the point where the force is applied and decreases as you move away from that point in the material. Different materials also have different abilities to distribute and withstand shear stress.

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