Machine Design_slide 8

Machine Design_slide 8 - Week5,Lecture1 FatigueFailure...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
ENGR 3220 – Machine Design ENGR 3220 – Machine Design Week 5, Lecture 1 Week 5, Lecture 1 Fatigue Failure Fatigue Failure
Image of page 1

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

View Full Document Right Arrow Icon
Fatigue Failure Machine members are found to have failed under the action of repeated or fluctuating stresses even the actual maximum stresses were well below the ultimate strength of the material or even below the yield strength. The most distinguishing characteristic of these failures is that the stresses have been repeated a very large number of times , these failures are called fatigue failures . Fatigue failure is due to crack formation and propagation . A fatigue crack will initiate at a discontinuity in the material where cyclic stress is a maximum. Various conditions that accelerate crack initiation include residual tensile stresses, elevated temperatures, temperature cycling, a corrosive environment, and high-frequency cycling.
Image of page 2
Fatigue Failure Fatigue failure has three stages of development: Stage I : initiation: one or more cracks Stage II : propagation: from microcracks to macrocracks Stage III : fast fracture Fatigue failure of a bolt due to repeated unidirectional bending.
Image of page 3

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

View Full Document Right Arrow Icon
Image of page 4
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