Text book for the mechanics of materials Strain ・Strain ・Normal & Lateral Strain ・Shear Strain Note: Your feedback is welcome!

1. Strain
1. Strain
Goal
2. Normal & Lateral Strain
3. Shear Strain
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2. Which deformation is large？
100 mmOriginal
Length
60 mm
10 N
10 N
Total deformation depends on original length !
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→ characterize as material property

3. Strain
Elongation per unit length
[ non-dimensional quantity]
Normal Strain
Shear Strain
ε
γ
：
：
Lateral Strainε’：
epsilon
gamma
epsilon prime
Mode and Symbol
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4. Normal & Lateral Strain
l
d
PP
l ＋ Δl
d＋ Δd
ε ＝
Δl
l
Parallel to load
Normal Strain
ε’＝
Δd
d
Perpendicular to load
Lateral Strain
2D
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5. Shear Stress
P
P
l
γ ＝
l
Δl
Δl ＝ tanl ∠ c’b c
γ ＝
l
Δl ~−∠ c’b c
Δl ~− l ∠ c’b c
∠ c’b c 0∵(
)
~−
∠ a b cAngle variation ofShear Stress ＝
Δl
a
b c
d
c’
d’
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6. Summary
1. Normal Strain
2. Lateral Strain
3. Shear Strain
Elongation per Unit Length [ - ]
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