Resolved Shear Stress Compared w/ Shear Stress-Contradictioni

AI Thread Summary
The discussion focuses on the relationship between shear stress and resolved shear stress in materials under uniaxial tensile stress. Key terms include slip plane and slip direction, which are critical for understanding the mechanics involved. The derivation of shear stress is presented as τ = σsinθcosθ, while resolved shear stress is expressed as τ = σcosλcosφ. The user seeks clarification on how these two formulations relate geometrically. The conversation emphasizes the importance of ensuring that the slip direction lies on the slip plane for accurate calculations.
ltkach2015
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TERMS:
Slip Plane: is the plane that has the densest atomic packing—that is, has the greatest planar density.
Slip Direction: corresponds to the direction in this plane that is most closely packed with atoms—that is, has the highest linear density.
TEXTBOOK: Materials Science and Engineering: An Introduction: William D. Callister. Chapter 6 & 7.
ASSUMPTIONS:

-uniaxial tensile stress of a material with moderate ductility
-quasi-static
NOMENCLATURE:
θ = angle of the slip plane as measured from cross section of material
λ = angle of that the applied force makes with the slip direction
φ = it has been said that is the angle between the normal vector and the applied force
θ = angle of the slip plane as measured from the cross section of the material
φ = θ =?; would this be so?
[A][/o] = Area of the materials cross section
A = Area of the slip plane

QUESTION:
Can you show the relationship between shear stress for a typical uniaxial tensile stress (mechanics of materials) to the resolved shear stress geometrically?

It is derived from mechanics of materials principles in Chapter 6 that shear stress is τ = σsinθcosθ. Following that chapter 7 introduces resolved shear stress τ=σcosλcosφ.

I can do both derivations but I cannot relate the two.

ATTACHMENTS: 1(

BEGIN:
-Derivation of resolved shear stress
0) ensure that slip direction lies on slip plane via dot product of the normal vector of the slip plane and the slip direction == 0 (orthogonal)

1) Load in direction of slip direction

τ=σcosλ/A;
[A][/o] = Acosθ
=> τ=σcosλcosφ.-Derivation of shear stress in general:
I can derive via a force balance, sum of forces resulting that resulted to

=> τ = σsinθcosθThank you!
 

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