Rotation of Angle Members

I have a couple of questions concerning the rotation of singe angle members.  Which command should I use to rotate these angle members?  "Beta Angle" or "Beta 45" (or 135 or 225 or whatever your required angle is)?  I pose this question because I would have thought the results would have been the same but they are not.  The results for "Beta Angle" actually match those of an angle member modeled along its principal axis with no rotation or "Beta 0".  I also would have thought the properties for the weld design, namely Sz, Sy, CH & CV, would have changed with this "Beta Angle" command since the member end forces are no longer being applied in the same manner to the weld.  Any thoughts?

Parents
  • It is different in different cases, we use. Mostly Frame. Here is the fundamental issue – Loads applied to the Geometrical Axis of the member’s local axis (not the principal axis of the angle or Z-shape used in purlins).  Principal axes are internal to calculate, not much interest of end users. Application of external loads are important to users.  Why users have to find Each equal or unequal angle or Z-shape where is the principal axes.  If designer changes the Equal or unequal angles and plays with it, users do not need to know how the beta angle are changing.  This is the fundamental to use geometrical axis. All steel Manuals have geometrical axes not principal axes.
     
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  • It is different in different cases, we use. Mostly Frame. Here is the fundamental issue – Loads applied to the Geometrical Axis of the member’s local axis (not the principal axis of the angle or Z-shape used in purlins).  Principal axes are internal to calculate, not much interest of end users. Application of external loads are important to users.  Why users have to find Each equal or unequal angle or Z-shape where is the principal axes.  If designer changes the Equal or unequal angles and plays with it, users do not need to know how the beta angle are changing.  This is the fundamental to use geometrical axis. All steel Manuals have geometrical axes not principal axes.
     
Children