Lecture10 - Chapter 6 - 1 ISSUES TO ADDRESS... • Stress...

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

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 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 Chapter 6 - 2 Why do we care about mechanical properties of materials? An oil barge fractured in a brittle manner by crack propagation around its girth Chapter 6 - 3 Why care? Structural failure of a ladder Failure can result from poor design – choice of material versus load Structural failure - is driven by repeat loading, which is a necessary requirement of • a ladder, • a drive shaft on an automobile, • and the wing on an airplane. Heverill Fire Department aerial ladder failure. Chapter 6 - 4 Elastic means reversible ! Elastic Deformation 1. Initial 2. Small load 3. Unload F δ bonds stretch return to initial F δ Linear- elastic Non-Linear- elastic Chapter 6 - 5 Plastic means permanent ! Plastic Deformation (Metals) F δ linear elastic linear elastic δ plastic 1. Initial 2. Small load 3. Unload planes still sheared F δ elastic + plastic bonds stretch & planes shear δ plastic Chapter 6 - 6 • Simple tension: cable τ Common States of Stress A o = cross sectional area (when unloaded) F F o σ = F A o τ = F s A σ σ M M A o 2 R F s A c • Torsion (a form of shear): drive shaft Ski lift (photo courtesy P.M. Anderson) Chapter 6 - 7 (photo courtesy P.M. Anderson) Canyon Bridge, Los Alamos, NM o σ = F A • Simple compression: Note: compressive structure member ( σ < 0 here)....
View Full Document

This note was uploaded on 04/06/2008 for the course MSE 201 taught by Professor Brenner during the Spring '08 term at N.C. State.

Page1 / 27

Lecture10 - Chapter 6 - 1 ISSUES TO ADDRESS... • Stress...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online