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# A.2 User subroutine functions listing

The following tables describe the function of each available user subroutine.

Abaqus/Standard User Subroutines 

<table><tr><td>Name</td><td>Function</td></tr><tr><td>CREEP</td><td>User subroutine to define time-dependent, viscoplastic behavior (creep and swelling).</td></tr><tr><td>DFLOW</td><td>User subroutine to define nonuniform pore fluid velocity in a consolidation analysis.</td></tr><tr><td>DFLUX</td><td>User subroutine to define nonuniform distributed flux in a heat transfer or mass diffusion analysis.</td></tr><tr><td>DISP</td><td>User subroutine to specify prescribed boundary conditions.</td></tr><tr><td>DLOAD</td><td>User subroutine to specify nonuniform distributed loads.</td></tr><tr><td>FILM</td><td>User subroutine to define nonuniform film coefficient and associated sink temperatures for heat transfer analysis.</td></tr><tr><td>FLOW</td><td>User subroutine to define nonuniform seepage coefficient and associated sink pore pressure for consolidation analysis.</td></tr><tr><td>FRIC</td><td>User subroutine to define frictional behavior for contact surfaces.</td></tr><tr><td>FRIC_COEF</td><td>User subroutine to define the frictional coefficient for contact surfaces.</td></tr><tr><td>GAPCON</td><td>User subroutine to define conductance between contact surfaces or nodes in a fully coupled temperature-displacement analysis, coupled thermal-electrical-structural analysis, or pure heat transfer analysis.</td></tr><tr><td>GAPELECTR</td><td>User subroutine to define electrical conductance between surfaces in a coupled thermal-electrical or a coupled thermal-electrical-structural analysis.</td></tr><tr><td>HARDINI</td><td>User subroutine to define initial equivalent plastic strain and initial backstress tensor.</td></tr><tr><td>HETVAL</td><td>User subroutine to provide internal heat generation in heat transfer analysis.</td></tr><tr><td>MPC</td><td>User subroutine to define multi-point constraints.</td></tr><tr><td>ORIENT</td><td>User subroutine to provide an orientation for defining local material directions or local directions for kinematic coupling constraints or local rigid body directions for inertia relief.</td></tr><tr><td>RSURFU</td><td>User subroutine to define a rigid surface.</td></tr><tr><td>SDVINI</td><td>User subroutine to define initial solution-dependent state variable fields.</td></tr><tr><td>SIGINI</td><td>User subroutine to define an initial stress field.</td></tr><tr><td>UAMP</td><td>User subroutine to specify amplitudes.</td></tr><tr><td>UANISOHYPER_INV</td><td>User subroutine to define anisotropic hyperelastic material behavior using the invariant formulation.</td></tr></table>

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<table><tr><td>UANISOHYPER_STRAIN</td><td>User subroutine to define anisotropic hyperelastic material behavior based on Green strain.</td></tr><tr><td>UCORR</td><td>User subroutine to define cross-correlation properties for random response loading.</td></tr><tr><td>UCREEPNETWORK</td><td>User subroutine to define time-dependent behavior (creep) for models defined within the parallel rheological framework.</td></tr><tr><td>UDECURRENT</td><td>User subroutine to define nonuniform volume current density in an eddy current or magnetostatic analysis.</td></tr><tr><td>UDEMPOTENTIAL</td><td>User subroutine to define nonuniform magnetic vector potential on a surface in an eddy current or magnetostatic analysis.</td></tr><tr><td>UDMGINI</td><td>User subroutine to define the damage initiation criterion.</td></tr><tr><td>UDSECURRENT</td><td>User subroutine to define nonuniform surface current density in an eddy current or magnetostatic analysis.</td></tr><tr><td>UEL</td><td>User subroutine to define an element.</td></tr><tr><td>UELMAT</td><td>User subroutine to define an element with access to Abaqus materials.</td></tr><tr><td>UEXPAN</td><td>User subroutine to define incremental thermal strains.</td></tr><tr><td>UEXTERNALDB</td><td>User subroutine to manage user-defined external databases and calculate model-independent history information.</td></tr><tr><td>UFIELD</td><td>User subroutine to specify predefined field variables.</td></tr><tr><td>UFLUID</td><td>User subroutine to define fluid density and fluid compliance for hydrostatic fluid elements.</td></tr><tr><td>UFLUIDCONNECTORLOSS</td><td>User subroutine to define the loss coefficient for fluid flow in fluid pipe connector elements.</td></tr><tr><td>UFLUIDCONNECTORVALVE</td><td>User subroutine to define the valve opening to control flow in fluid pipe connector elements.</td></tr><tr><td>UFLUIDLEAKOFF</td><td>User subroutine to define the fluid leak-off coefficients for pore pressure cohesive elements.</td></tr><tr><td>UFLUIDPIPEFRICTION</td><td>User subroutine to define the frictional coefficient for fluid flow in fluid pipe elements.</td></tr><tr><td>UGENS</td><td>User subroutine to define the mechanical behavior of a shell section.</td></tr><tr><td>UHARD</td><td>User subroutine to define the yield surface size and hardening parameters for isotropic plasticity or combined hardening models.</td></tr><tr><td>UHYPEL</td><td>User subroutine to define a hypoelastic stress-strain relation.</td></tr><tr><td>UHYPER</td><td>User subroutine to define a hyperelastic material.</td></tr><tr><td>UINTER</td><td>User subroutine to define surface interaction behavior for contact surfaces.</td></tr><tr><td>UMASFL</td><td>User subroutine to specify prescribed mass flow rate conditions for a convection/diffusion heat transfer analysis.</td></tr><tr><td>UMAT</td><td>User subroutine to define a material&#x27;s mechanical behavior.</td></tr><tr><td>UMATHT</td><td>User subroutine to define a material&#x27;s thermal behavior.</td></tr></table>

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<table><tr><td>UMESHMOTION</td><td>User subroutine to specify mesh motion constraints during adaptive meshing.</td></tr><tr><td>UMOTION</td><td>User subroutine to specify motions during cavity radiation heat transfer analysis or steady-state transport analysis.</td></tr><tr><td>UMULLINS</td><td>User subroutine to define damage variable for the Mullins effect material model.</td></tr><tr><td>UPOREP</td><td>User subroutine to define initial fluid pore pressure.</td></tr><tr><td>UPRESS</td><td>User subroutine to specify prescribed equivalent pressure stress conditions.</td></tr><tr><td>UPSD</td><td>User subroutine to define the frequency dependence for random response loading.</td></tr><tr><td>URDFIL</td><td>User subroutine to read the results file.</td></tr><tr><td>USDFLD</td><td>User subroutine to redefine field variables at a material point.</td></tr><tr><td>UTEMP</td><td>User subroutine to specify prescribed temperatures.</td></tr><tr><td>UTRACLOAD</td><td>User subroutine to specify nonuniform traction loads.</td></tr><tr><td>UTRS</td><td>User subroutine to define a reduced time shift function for a viscoelastic material.</td></tr><tr><td>UTRSNETWORK</td><td>User subroutine to define a reduced time shift function for models defined within the parallel rheological framework.</td></tr><tr><td>UVARM</td><td>User subroutine to generate element output.</td></tr><tr><td>UWAVE</td><td>User subroutine to define wave kinematics for an Abaqus/Aqua analysis.</td></tr><tr><td>UXFEMNONLOCALWEIGHT</td><td>User subroutine to define the weight function used to compute the average stress/strain to determine the crack propagation direction.</td></tr><tr><td>VOIDRI</td><td>User subroutine to define initial void ratios.</td></tr></table>

Abaqus/Explicit User Subroutines 

<table><tr><td>Name</td><td>Function</td></tr><tr><td>VDFLUX</td><td>User subroutine to specify nonuniform distributed fluxes in an explicit dynamic coupled temperature-displacement analysis.</td></tr><tr><td>VDISP</td><td>User subroutine to specify prescribed boundary conditions.</td></tr><tr><td>VDLOAD</td><td>User subroutine to specify nonuniform distributed loads.</td></tr><tr><td>VEXTERNALDB</td><td>User subroutine that gives control to the user at key moments of the analysis so that data can be exchanged dynamically among Abaqus user subroutines and with external programs or files.</td></tr><tr><td>VFABRIC</td><td>User subroutine to define fabric material behavior.</td></tr><tr><td>VFRIC</td><td>User subroutine to define frictional behavior for contact surfaces.</td></tr><tr><td>VFRIC_COEF</td><td>User subroutine to define the frictional coefficient for contact surfaces.</td></tr><tr><td>VFRICTION</td><td>User subroutine to define frictional behavior for contact surfaces.</td></tr><tr><td>VUAMP</td><td>User subroutine to specify amplitudes.</td></tr></table>

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<table><tr><td>VUANISOHYPER_INV</td><td>User subroutine to define anisotropic hyperelastic material behavior using the invariant formulation.</td></tr><tr><td>VUANISOHYPER_STRAIN</td><td>User subroutine to define anisotropic hyperelastic material behavior based on Green strain.</td></tr><tr><td>VUCHARLENGTH</td><td>User subroutine to define characteristic element length at a material point.</td></tr><tr><td>VUCREEPNETWORK</td><td>User subroutine to define time-dependent behavior (creep) for models defined within the parallel rheological framework.</td></tr><tr><td>VUEL</td><td>User subroutine to define an element.</td></tr><tr><td>VUEOS</td><td>User subroutine to define equation of state material model.</td></tr><tr><td>VUFIELD</td><td>User subroutine to specify predefined field variables.</td></tr><tr><td>VUFLUIDEXCH</td><td>User subroutine to define the mass flow rate/heat energy flow rate for fluid exchange.</td></tr><tr><td>VUFLUIDEXCHEFFAREA</td><td>User subroutine to define the effective area for fluid exchange.</td></tr><tr><td>VUHARD</td><td>User subroutine to define the yield surface size and hardening parameters for isotropic plasticity or combined hardening models.</td></tr><tr><td>VUINTER</td><td>User subroutine to define the interaction between contact surfaces.</td></tr><tr><td>VUINTERACTION</td><td>User subroutine to define the contact interaction between surfaces with the general contact algorithm.</td></tr><tr><td>VUMAT</td><td>User subroutine to define material behavior.</td></tr><tr><td>VUMULLINS</td><td>User subroutine to define damage variable for the Mullins effect material model.</td></tr><tr><td>VUSDFLD</td><td>User subroutine to redefine field variables at a material point.</td></tr><tr><td>VUTRS</td><td>User subroutine to define a reduced time shift function for a viscoelastic material.</td></tr><tr><td>VUVISCOSITY</td><td>User subroutine to define the shear viscosity for equation of state models.</td></tr><tr><td>VWAVE</td><td>User subroutine to define wave kinematics for an Abaqus/Aqua analysis.</td></tr></table>

Abaqus/CFD User Subroutines

<table><tr><td>Name</td><td>Function</td></tr><tr><td>SMACfdUserPressureBC</td><td>User subroutine to specify prescribed pressure boundary conditions.</td></tr><tr><td>SMACfdUserVelocityBC</td><td>User subroutine to specify prescribed velocity boundary conditions.</td></tr></table>

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