*SetBeam() - arbitrary cross section symmetric pair
Sets the properties of a symmetric beam pair with arbitrary cross section.
Syntax
*SetBeam(beam_name,     LEFT|RIGHT, ARBITRARY, 
                                  len|AUTO_LENGTH,
                                  E,          G,         area, 
                                  ixx,        iyy,       izz, 
                                  asy,        asz, 
                                  CRATIO,     ratio)
    Arguments
- beam_name
 - The variable name of an existing beam pair.
 - LEFT RIGHT
 - If LEFT is specified, the properties are assigned to the left beam, and the right beam properties are made symmetric to the left beam.
 - ARBITRARY
 - This argument indicates cross section of the beam is arbitrary.
 - len
 - len specifies the undeformed length of the beam.
 - AUTO_LENGTH
 - AUTO_LENGTH indicates that the undeformed length of the beam is calculated automatically using the end points of the beam.
 - E
 - The Young's modulus of elasticity.
 - G
 - The shear modulus of elasticity.
 - area
 - Area of the beam's cross section.
 - ixx
 - Polar moment of inertia of the beam cross section.
 - iyy
 - Second moment of inertia of the beam cross section bout the Y axis.
 - izz
 - Second moment of inertia of the beam cross section about the Z axis.
 - asy
 - The correction factor for the shear deflection along the Y axis of the beam.
 - asz
 - The correction factor for the shear deflection along the Z axis of the beam.
 - CRATIO
 - This argument indicates that the structural damping matrix is a ratio of the stiffness matrix.
 - ratio
 - Ratio for calculating the damping matrix.
 
Example
*SetBeam(bm1, LEFT, ARBITRARY, 
 1000, 200000, 75000
 100, 1000, 100000, 200000, 
 
 0, 
 0, 
 CRATIO, 
3.0)