재료의기계적거동 (Mechanical Behavior of Materials) 02... · 2018. 4. 17. ·...
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재료의 기계적 거동 (Mechanical Behavior of Materials) Lecture 2 – Overview of Mechanical Behavior (1-dimensional definition of stress and strain) Heung Nam Han Professor Department of Materials Science & Engineering College of Engineering Seoul National University Seoul 151-744, Korea Tel : +82-2-880-9240 Fax : +82-2-885-9647 email : [email protected] Office hours : Tuesday, Thursday 15:30~17:00 Homepage : http://mmmpdl.snu.ac.kr 2016-03-08
Transcript of 재료의기계적거동 (Mechanical Behavior of Materials) 02... · 2018. 4. 17. ·...
재료의 기계적 거동(Mechanical Behavior of Materials)
Lecture 2 – Overview of Mechanical Behavior
(1-dimensional definition of stress and strain)
Heung Nam HanProfessor
Department of Materials Science & Engineering
College of Engineering
Seoul National University
Seoul 151-744, Korea
Tel : +82-2-880-9240
Fax : +82-2-885-9647
email : [email protected]
Office hours : Tuesday, Thursday 15:30~17:00
Homepage : http://mmmpdl.snu.ac.kr
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Tensile Test
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Tensile Test Specimen
A standard tensile specimen with circular cross section
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Engineering Stress and Strain
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Engineering Stress-Strain Curve
Initial area
Extension/initial length
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True Stress and Strain
* Incompressibility
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Engineering Strain
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Stress-Strain Curves
dσ/dε
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Strain Hardening and Necking
ε<εu ε>εu
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Holloman Equation
where σ is the true stress, ε is
true strain, K is strength
coefficient, and n is the
strain-hardening exponent.
n=εu
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UYP, LYP and serration
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Strain rate sensitivity & Temperature effect
