Chapter 2 - Strain

Objectives Course objective:  To understand normal and shear strains and how they relate to deformation. Learning objectives: Identify the Greek symbols associated with normal and shear strain. Draw (or recognize the correct) free-body diagrams of frames/machines. Draw deformation diagrams of frames/machines. Derive the compatibility relationship for coaxial (1.19), end-to-end or rotating rigid (0.99) components. Judge whether a modification of the basic compatibility relationship is necessary in order to deal with gaps in the structure (0.95, 0.71). Convert to consistent units of length (in., ft, mm, m) and strain (in./in., m/m, mm/mm, deg., rad). Calculate normal strains (1.06). Calculate shear strains using trigonometry (0.89). Judge whether to add or subtract when using multiple angles. Calculate thermal strains and deformations (1.06). 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  (13 minutes) 1. stress at a point video notes 2. normal strain video notes 3. shear strain video notes 4. shear-strain comparison video 5. thermal strain video notes 6. examples video notes

Demos  (8 minutes) 1. rubber band video 2. foam video 3. deck of cards video 4. shear strain from torsion video 5. strain gages video 6. strain indicator video 7. concrete strain gage video 8. thermal strain video     - Modular Expansion Joint YouTube     - I-90 Bridge Expansion Joint Installation YouTube     - Expansion and Contraction YouTube

Problems  (18 minutes) assigned 3e 2e 1e aids WP format   normal strain yes   02.001   02.001* 02.001 strategy   solution TENU     yes   --   02.002* 02.002 video   solution TENU B23       --   02.002   --   --   --   --   TENU     --   02.003   02.003* 02.003 strategy   solution TENU     yes   02.004   02.004* 02.004 strategy   solution GO     --   02.005   02.005* 02.005 video   solution --     yes   02.006   02.006 02.006 --   solution TENU     --   02.007   02.007 02.007 --   solution --     --   02.008   02.008 02.008 --   solution TENU     shear strain yes   02.009   02.009 02.009 strategy   solution TENU     yes   02.010   02.010* 02.010 video   solution TENU     --   02.011   02.011* 02.011 strategy   solution --     yes   --   02.012* 02.012 strategy   solution TENU B24       --   02.012   --   --   --   --   TENU     yes   --   02.013* 02.013 video   solution TENU B25       --   02.013   --   --   --   --   --     --   --   02.014* 02.014 strategy   solution TENU B26       --   02.014   --   --   --   --   GO     thermal strain yes   02.015   02.015* 02.015 strategy   solution TENU     --   --   02.016* 02.016 strategy   solution TENU B27       --   02.016   --   --   --   --   TENU     yes   02.017   02.017* 02.017 strategy   solution TENU       --   02.018   02.018   --   --   --   TENU       --   02.019   02.019   --   --   --   TENU     --   02.020   02.020 02.018 --   solution --     --   02.021   02.021* 02.019 --   solution --     --   02.022   02.022 02.020 --   solution GO     --   02.023   02.023 02.021 --   solution TENU       --   02.024   --   --   --   --   TENU   * numbers changed between first and second editions props