Chapter 3 - Mechanical Properties of Materials

Objectives Course objectives: To interpret a stress-strain diagram and understand elastic constants. To understand the stress-strain relationship for axial force members. Learning objectives: Identify the terminology and symbols associated with tension tests. Identify elastic, yield, strain-hardening, ultimate and necking regions of basic stress-strain diagrams. Read/calculate commonly used values from basic stress-strain diagrams: Young's modulus (0.85), proportional limit (1.06), yield strength (1.00), ultimate strength (0.95), fracture strength (1.00), true fracture strength (0.66). Convert between normal stress and normal strain using Hooke's Law relationship (1.08). Calculate Poisson's ratio from changes in axial and transverse strains and deformations (1.08). Calculate shear modulus from shear stress and shear strain (0.71). The values in orange represent quiz performance.  One represents average.  Values greater than one represent easier topics.  Values less than one represent harder topics.

Concepts  (14 minutes) 1. materials video notes 2. mechanical testing video notes 3. mechanical properties video notes 4. elastic constants video notes 5. homework strategies video

Demos  (7 minutes) 1. various tension tests video 2. LEGO video 3. paperclip video 4. why stress and strain? video

Quiz Prep 1. The first quiz usually covers chapters 1, 2 and 3.  Look at the Grades page from previous semesters to see how many questions usually come from each chapter, how many calculation versus concept questions are used, etc. 2. Calculations questions will be similar to the non-gray problems listed below and in the other chapter pages and in the MecMovies. 3. Concept questions generally come from the textbook, videos, and MecMovies.  You are also encouraged to reflect upon the homework problems after you have completed them.  Compare and contrast the problems.  Why were some harder than others?  How could they be asked differently, i.e. what if you were asked to solve for a different value, the derivation steps were reversed, the problem shortened, the wording or image modified?   4. You will be given a packet of blank paper to write on.  Relevant portions of the formula sheet will be stapled to the packet.  Feel free to rip off the formula sheet(s) once the quiz begins.  Feel free to ask for additional blank paper if needed.  You are to turn in the packet once you complete the quiz. 5. Each calculation question will have five multiple-choice answers.  One answer will be correct.  The other four will be random numbers and incorrect.  There will be no partial credit.  Concept questions may be formatted as multiple-choice, true-false, matching, etc. 6. You may use the full class period to complete the quiz.

Problems  (15 minutes)       assigned   3e   2e   1e    aids   WP format     tensile properties   yes   03.001   03.001*   03.001 video solution TENU     yes   --   03.002*   03.002 strategy solution TENU B39     --   03.002   --   --   --   --   TENU       --   03.003   03.003   03.003 -- -- TENU     --   03.004   03.004*   03.004 strategy solution TENU     yes   03.005   03.005*   03.005 video solution TENU     --   --   03.006*   03.006 -- solution --     --   03.006   --   --   --   --   --       --   --   03.007   03.007 -- -- --     --   03.007   --   --   --   --   --       --   03.008   03.008   03.008 strategy solution TENU     --   03.009   03.009   03.009 -- -- --   shear properties   --   03.010   03.010   03.010 strategy solution TENU     yes   03.011   03.011   03.011 -- solution GO     yes   03.012   03.012   03.012 strategy solution TENU   tensile properties   yes   03.013   03.013*   03.013 -- -- GO     --   03.014   03.014   03.014 -- solution GO     --   03.015   03.015*   03.015 -- solution GO     yes   03.016   03.016   03.016 video solution --     --   03.017   03.017   03.017 strategy solution --     --   03.018   03.018   03.018 -- solution --     --   03.019   03.019   03.019 -- -- --     --   03.020   03.020   03.020 -- -- --     --   03.021   03.021   03.021 -- solution --     --   03.022   03.022   03.022 -- -- TENU   structural deformation   --   --   03.023*   03.023 -- solution GO B40     --   --   03.024   --   --   --   GO B41       --   03.023   03.025   --   --   --   GO       --   03.024   03.026*   03.024 -- solution GO     --   03.025   03.027*   03.025 -- -- TENU     --   03.026   03.028*   03.026 -- solution TENU * numbers changed between first and second editions props