rock

SpectrumOptions.rock(cgx='', cgy='', cgz='', omx='', omy='', omz='', **kwargs)

Specifies a rocking response spectrum.

Mechanical APDL Command: ROCK

Parameters:

cgxstr

Global Cartesian X, Y, and Z location of center of rotation about which rocking occurs.

cgystr

Global Cartesian X, Y, and Z location of center of rotation about which rocking occurs.

cgzstr

Global Cartesian X, Y, and Z location of center of rotation about which rocking occurs.

omxstr

Global Cartesian angular components of the rocking.

omystr

Global Cartesian angular components of the rocking.

omzstr

Global Cartesian angular components of the rocking.

Notes

Specifies a rocking response spectrum effect in the spectrum ( antype,SPECTR) analysis.

The excitation direction with rocking included is not normalized to one; rather, it scales the spectrum. For example, consider a node at coordinates (1,1,0), subject to an excitation in the X direction ( SEDX = 1.0 on sed ), and a rocking with center CGX = 1.0, CGY = CGZ = 0, and angular component about Z ( OMZ = 0.5). The total excitation direction at this node is:

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So that half the spectrum input is applied at this node.

For more information on the equations, see Participation Factors and Mode Coefficients

This command is also valid in PREP7.