1. mechnical properties of metal - Chapter 6 Mechanical...

Info icon This preview shows pages 1–11. Sign up to view the full content.

Chapter 6 - 1 ISSUES TO ADDRESS... Stress and strain : What are they and why are they used instead of load and deformation? Elastic behavior: When loads are small, how much deformation occurs? What materials deform least? Plastic behavior: At what point does permanent deformation occur? What materials are most resistant to permanent deformation? Toughness and ductility : What are they and how do we measure them? Chapter 6: Mechanical Properties
Image of page 1

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

Chapter 6 - 2 Mechanical Properties of Metals Material when in service are subjected to forces or loads. Thus it is necessary to know the characteristics of the material and to design the member so that deformation will not be excessive and fracture will not occur . Mechanical properties of material reflects the relationship between its responds or deformation to an applied force. Key mechanical design properties are: Stiffness, Strength Hardness Ductility Toughness
Image of page 2
Chapter 6 - 3 Elastic means reversible ! Elastic Deformation 2. Small load F bonds stretch 1. Initial 3. Unload return to initial F Linear- elastic Non-Linear- elastic
Image of page 3

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

Chapter 6 - 4 Plastic means permanent ! Plastic Deformation (Metals) F linear elastic linear elastic plastic 1. Initial 2. Small load 3. Unload planes still sheared F elastic + plastic bonds stretch & planes shear plastic
Image of page 4
Chapter 6 - 5 Stress has units: N/m 2 Engineering Stress Shear stress, : Area, A o F t F t F s F F F s = F s A o Tensile stress, : original area before loading = F t A o 2 m N = Area, A o F t F t
Image of page 5

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

Chapter 6 - 6 Simple tension: cable Note: = M / A c R here. Common States of Stress o F A o F s A M M A o 2 R F s A c Torsion (a form of shear): drive shaft Ski lift (photo courtesy P.M. Anderson) A o = cross sectional area (when unloaded) F F
Image of page 6
Chapter 6 - 7 (photo courtesy P.M. Anderson) Canyon Bridge, Los Alamos, NM o F A Simple compression: Note: compressive structure member ( < 0 here). (photo courtesy P.M. Anderson) OTHER COMMON STRESS STATES (i) A o Balanced Rock, Arches National Park
Image of page 7

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

Chapter 6 - 8 Bi-axial tension: Hydrostatic compression: Pressurized tank < 0 h (photo courtesy P.M. Anderson) (photo courtesy P.M. Anderson) OTHER COMMON STRESS STATES (ii) Fish under water z > 0 > 0
Image of page 8
Chapter 6 - 9 Tensile strain: Lateral strain: Strain is always dimensionless. Engineering Strain Shear strain: is the tangent of the strain angle 90º 90º - y x = x / y = tan   L o Adapted from Fig. 6.1(a) and (c), Callister & Rethwisch 8e. /2 L o w o L L w o L /2
Image of page 9

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

Chapter 6 - 10 Stress-Strain Testing • Typical tensile test machine Adapted from Fig. 6.3, Callister & Rethwisch 8e. (Fig. 6.3 is taken from H.W.
Image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.
  • Spring '14
  • Strain, Tensile strength

{[ 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