Mohr's Circle in Three Dimensions

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Consider the state of stress given by

 

   is symmetric. When we determine the principal value, let  and  be the principal value.  Let   

and let the eigen vectors  ,

 and  be associated with  and

 

  Note that form a rectangular Cartesian coordinate system. If [Q] represents the transformation from  to ,  then

X-axis represents the eigen value with coordinate system . As we rotate the radius with arbitrary angles a, b and g with old system (eigen vector system) with

 

Thus

Thus Mohr's circle in three dimensions is the coordination transformation of any orientation of the stress cube from the cube when aligned with the principal orientation lying along the x-axis.

Next: 4-7 Equations of motion

10/18/01 0:53:51
10/23/01 0:00:51