Engine Subroutine RUSERnn for Spring Elements

This subroutine calculates the internal forces and moment versus the velocity, old forces, moments, and user’s variables and parameters.

Arguments

The argument list of RUSERnn and its individual arguments and descriptions are:

C--------------------------------------------------------------------------
     SUBROUTINE RUSERnn(NEL    ,IOUT   ,IPROP ,UVAR  ,NUVAR ,
    2                                      FX       ,FY       ,FZ       ,XMOM ,YMOM  ,
    3                                      ZMOM ,E         ,OFF    ,STIFM  ,STIFR   ,
    4                                      VISCM ,VISCR ,MASS ,XINER ,DT        ,
    5                                      XL       ,VX       ,RY1    ,RZ1       ,RX        ,
    6                                      RY2     ,RZ2      ,FR_WAVE)
C--------------------------------------------------------------------------

Definitions

Argument	Format	Description
`NEL`	Integer read only scalar	Number of elements per group. In Radioss Engine subroutines, the element data are treated by groups for vectorization. This argument is machine-dependent and set by Radioss.
`IOUT`	Integer read only scalar	Output file unit (ROOTL00).
`IPROP`	Integer read only scalar	Property number.
`UVAR`	Float array read write	Array of size `NEL`*`NUVAR` containing user element variables.
`NUVAR`	Integer read only scalar	Number of user element variables.
`FX`	Float array read write	Array of size `NEL` containing an internal local X force as input and a new force as output. Nodal X forces at nodes 1 and 2 in a local frame are defined as FX1 = FX and FX2 = -FX.
`FY`	Float array read write	Array of size `NEL` containing an internal local Y force as input and a new force as output. Nodal X forces at nodes 1 and 2 in a local frame are defined as FY1 = FY and FY2 = -FY.
`FZ`	Float array read write	Array of size `NEL` containing an internal local Z force as input and a new force as output. Nodal X forces at nodes 1 and 2 in a local frame are defined as FZ1 = FZ and FZ2 = -FZ.
`XMOM`	Float array read write	Array of size `NEL` containing an old internal local X moment as input and a new moment as output. Nodal X moments at nodes 1 and 2 in a local frame are defined as MX1 = MX and MX2 = -MX.
`YMOM`	Float array read write	Array of size `NEL` containing an old internal local Y moment as input and a new moment as output. Nodal Y moments at nodes 1 and 2 in a local frame are defined as MY1 = MY – 1/2XLFZ and MY2 = -MY – 1/2XLFZ.
`ZMOM`	Float array read write	Array of size `NEL` containing an old internal local Z moment as input and a new moment as output. Nodal Z moments at nodes 1 and 2 in a local frame are defined as MZ1 = MZ + 1/2XLFZ and MZ2 = -MZ – 1/2XLFZ.
`EINT`	Float array read only	Array of size `NEL` containing internal energy.
`OFF`	Float array read write	Array of size `NEL` containing deleted element flags. 0 If the element is OFF 1 If the element is ON
`STIFM`	Float array write only	Array of size `NEL` containing element translational stiffness in time step computation.
`STIFR`	Float array write only	Array of size `NEL` containing element rotational stiffness in time step computation.
`VISCM`	Float array write only	Array of size `NEL` containing element translational viscosity in time step computation.
`VISCR`	Float array write only	Array of size `NEL` containing element rotational viscosity in time step computation.
`MASS`	Flat array write only	Array of size `NEL` containing element mass in time step computation.
`XINER`	Float array write only	Array of size `NEL` containing element spherical inertia.
`DT`	Float read only	Current time step
`XL`	Float array read only	Array of size `NEL` containing element length
`VX`	Float array read only	Array of size `NEL` containing X velocity. Nodal velocities at nodes 1 and 2 in a local frame are defined as VX1 = -VX/2 and VX2 = VX/2.
`RY1`	Float array read only	Array of size `NEL` containing Y rotational velocity at node 1.
`RZ1`	Float array read only	Array of size `NEL` containing Z rotational velocity at node 1.
`RX`	Float array read only	Array of size `NEL` containing torsional velocity. Nodal torsional velocities at nodes 1 and 2 in a local frame are defined as RX1 = -RX/2 and RX2 = RX/2.
`RY2`	Float array read only	Array of size `NEL` containing Y rotational velocity at node 2.
`RZ2`	Float array read only	Array of size `NEL` containing Z rotational velocity at node 2.
`FR_WAVE`	Float array read only	Array of size `NEL` not yet used.