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Geology 3120 - Resolving stresses on a plane. Outline. Resolving stress on a plane Determining maximum shear stress Class problem. Stress. Normal and Shear Stresses. Q is defined as the angle from horizontal to the plane A’. Counterclockwise is positive (+). . Solving for Shear Stress.
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Outline • Resolving stress on a plane • Determining maximum shear stress • Class problem
Normal and Shear Stresses Q is defined as the angle from horizontal to the plane A’. Counterclockwise is positive (+).
Calculating Maximum Shear Stress For what Q value is the shear stress greatest?
Calculating Maximum Shear Stress p/4 For what Q value is the shear stress greatest? Q = 45° or p/4 F A Q
Class Problem Find the Q dip value of the plane such that ss is minimized and sn maximized. F Draw the plane on the block figure. A
Class Problem Find the Q dip value of the plane such that ss is minimized and sn maximized. F Draw the plane on a block figure. A Q = 0°
The Relationship Between Stresses and Q F/A = 1 sn s ss p/2 p/4 0 Q
References Slide 1 Twiss, R. J. and E. M. Moores, Structural Geology, W. H. Freeman & Co., New York, 532 p., 1992.