Extra Credit Problem Set
Skills and concepts that students must have mastered
For part 2 they need to know what lithostatic stress is, the rules of trigonometry, and they will have to use algebra.
For part 3 they need to know how to calculate max. stress, min. stress, mean stress, differential stress, and deviatoric stress given two of those stresses, and be able to draw Mohr circles and associated failure envelopes, and calculate the equation of the failure envelope and the angles between the fracture plane and sigma-1.
How the activity is situated in the course
Content/concepts goals for this activity
Deriving normal and shear stress on an inclined surface.
Constructing and interpreting Mohr stress circles.
Higher order thinking skills goals for this activity
Other skills goals for this activity
Description and Teaching Materials
This exercise was assigned as an extra credit problem set to help students review and prepare for the final exam. It includes 1) measurements of strain: stretching, angular shear, and determination of coaxial vs. noncoaxial deformation, 2) derivation of equations for normal and shear stress on an inclined surface (not quite the full stress equations though), and 3) constructing Mohr stress circles from given data, and determining the equation of the failure envelope and the resultant fracture angles.End of year problem set (Microsoft Word 2007 (.docx) 151kB May4 12)