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Description
Stress, a core and essential concept in structural geology, is conceptually difficult for many undergraduate students. Part of the difficult is that the description of stress is inherently mathematical and thus to many students non-intuitive. Moreover, graphing, and/or calculating and converting to the various units of stress is a time consuming task that many students view as "busy work" or "mundane". In an attempt to cut-down on the amount of "busy work" needed to perform a simple stress analysis, a software program termed Stress Analysis 98, was written in Visual Basic 5. In addition, a detailed tutorial on the mathematics of stress and how to use Stress Analysis 98 to solve basic problems in stress analysis was written to accompany dissemination of the program. Essential topics covered in the tutorial include: (1) how force relates to stress using Newton's first and second laws, (2) the units of stress and how to convert one to another, (3) how tractions are defined and calculated, (4) how lithostatic pressures are calculated, (5) a graphical approach to understanding the stress tensor and how it relates to the definition of a-1, a-2,and a-3, (6) derivation of the normal and shear stress equations that define the Mohr circle of stress, (7) a graphical approach to using the Mohr circle for solving stress problems when two of the three principal stress directions and their magnitudes are known, (8) the effect of pore pressures on stress, and (9) Mohr Failure Envelope as approached from a graphical analysis of triaxial stress test data extracted from the literature. Stress Analysis 98 is currently a version that will undergo extensive testing in the Advanced Structural Geology and Introduction to Structural Geology classes at San Diego State University. Eventually, it is the authors' intentions that the program and tutorial will be offered to the general geological community through a paper published in the Journal of Geoscience Education.
