L27MechI145s09 - Lecture 27 Mechanical Properties I Elastic...

Info icon This preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 27, spring 2009 ENGR 145, Chemistry of Materials Case Western Reserve University Reading assignment : C&R §7.1-7.5; 7.11 Learning objectives: Know how to compute engineering stress and strain Understand properties related to elastic behavior: Elastic modulus Poisson’s ratio Proportional limit Modulus of resilience Understand the relationship of elastic modulus to bonding and the interatomic potential Distinguish the elastic behaviors of metals, ceramics, and polymers Lecture 27: Mechanical Properties I — Elastic Behavior 1
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 Lecture 27, spring 2009 ENGR 145, Chemistry of Materials Case Western Reserve University Engineering Stress & Strain [C&R §7.2] C&R Fig. 7.1 σ F A 0 ε L L 0 tension
Image of page 2
3 Lecture 27, spring 2009 ENGR 145, Chemistry of Materials Case Western Reserve University Engineering Stress & Strain [C&R §7.2] σ F A 0 ε L L 0 compression tension C&R Fig. 7.1
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
4 Lecture 27, spring 2009 ENGR 145, Chemistry of Materials Case Western Reserve University Poisson’s Ratio [C&R §7.5] v ≡ - ε x ε z = - ε y ε z Poisson’s ratio Elastic dimensional change will occur transverse to applied uniaxial load: 0.20-0.35 for most inorganic materials; 0.30-0.46 for most polymers C&R Fig. 7.9
Image of page 4
5 Lecture 27, spring 2009 ENGR 145, Chemistry of Materials Case Western Reserve University C&R Figs. 7.2 & 7.3 Tensile Test Specimen [C&R §7.2] C&R Fig. 7.2
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
6 Lecture 27, spring 2009 ENGR 145, Chemistry of Materials Case Western Reserve University Measure force w/load cell compute stress Measure elongation w/extensometer compute strain Tensile Test Apparatus [C&R §7.2] C&R Fig. 7.3
Image of page 6
Lecture 27, spring 2009 ENGR 145, Chemistry of Materials Case Western Reserve University Elasticity vs. Plasticity [C&R §7.2] Elastic behavior ε 0 when σ 0 I.e., reversible deformation — no permanent shape change after load is removed Plastic behavior ε≠0 when σ 0 I.e., some strain remains after load has been removed — more about this later 7
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern