The available user subroutines for Abaqus/Standard are as follows:

• CREEP: Define time-dependent, viscoplastic behavior (creep and swelling).

• DFLOW: Define nonuniform pore fluid velocity in a consolidation analysis.

• DFLUX: Define nonuniform distributed flux in a heat transfer or mass diffusion analysis.

• DISP: Specify prescribed boundary conditions.

• DLOAD: Specify nonuniform distributed loads.

• FILM: Define nonuniform film coefficient and associated sink temperatures for heat transfer analysis.

• FLOW: Define nonuniform seepage coefficient and associated sink pore pressure for consolidation analysis.

• FRIC: Define frictional behavior for contact surfaces.

• FRIC_COEF: Define frictional coefficient for contact surfaces.

• GAPCON: Define conductance between contact surfaces or nodes in a fully coupled temperature-displacement analysis, a fully coupled thermal-electrical-structural analysis, or a pure heat transfer analysis.

• GAPELECTR: Define electrical conductance between surfaces in a coupled thermal-electric analysis or a fully coupled thermal-electrical-structural analysis.

• HARDINI: Define initial equivalent plastic strain and initial backstress tensor.

• HETVAL: Provide internal heat generation in heat transfer analysis.

• MPC: Define multi-point constraints.

• ORIENT: Provide an orientation for defining local material directions or local directions for kinematic coupling constraints or local rigid body directions for inertia relief.

• RSURFU: Define a rigid surface.

• SDVINI: Define initial solution-dependent state variable fields.

• SIGINI: Define an initial stress field.

• UAMP: Specify amplitudes.

• UANISOHYPER_INV: Define anisotropic hyperelastic material behavior using the invariant formulation.

• UANISOHYPER_STRAIN: Define anisotropic hyperelastic material behavior based on Green strain.

• UCORR: Define cross-correlation properties for random response loading.

• UDECURRENT: Define nonuniform volume current density in an eddy current or magnetostatic analysis.

• UDEMPOTENTIAL: Define nonuniform magnetic vector potential on a surface in an eddy current or magnetostatic analysis.

• UDMGINI: Define the damage initiation criterion.

• UDSECURRENT: Define nonuniform surface current density in an eddy current or magnetostatic analysis.

• UEL: Define an element.

• UELMAT: Define an element with access to Abaqus materials

• UEXPAN: Define incremental thermal strains.

• UEXTERNALDB: Manage user-defined external databases and calculate model-independent history information.

• UFIELD: Specify predefined field variables.

• UFLUID: Define fluid density and fluid compliance for hydrostatic fluid elements.

• UFLUIDLEAKOFF: Define the fluid leak-off coefficients for pore pressure cohesive elements.

• UGENS: Define the mechanical behavior of a shell section.

• UHARD: Define the yield surface size and hardening parameters for isotropic plasticity or combined hardening models.

• UHYPEL: Define a hypoelastic stress-strain relation.

• UHYPER: Define a hyperelastic material.

• UINTER: Define surface interaction behavior for contact surfaces.

• UMASFL: Specify prescribed mass flow rate conditions for a convection/diffusion heat transfer analysis.

• UMAT: Define a material's mechanical behavior.

• UMATHT: Define a material's thermal behavior.

• UMESHMOTION: Specify mesh motion constraints during adaptive meshing.

• UMOTION: Specify motions during cavity radiation heat transfer analysis or steady-state transport analysis.

• UMULLINS: Define damage variable for the Mullins effect material model.

• UPOREP: Define initial fluid pore pressure.

• UPRESS: Specify prescribed equivalent pressure stress conditions.

• UPSD: Define the frequency dependence for random response loading.

• URDFIL: Read the results file.

• USDFLD: Redefine field variables at a material point.

• UTEMP: Specify prescribed temperatures.

• UTRACLOAD: Specify nonuniform traction loads.

• UTRS: Define a reduced time shift function for a viscoelastic material.

• UVARM: Generate element output.

• UWAVE: Define wave kinematics for an Abaqus/Aqua analysis.

• VOIDRI: Define initial void ratios.

The available user subroutines for Abaqus/Explicit are as follows:

• VDISP: Specify prescribed boundary conditions.

• VDLOAD: Specify nonuniform distributed loads.

• VFABRIC: Define fabric material behavior.

• VFRIC: Define contact frictional behavior between surfaces defined with the contact pair algorithm.

• VFRIC_COEF: Define contact frictional coefficient between surfaces defined with the general contact algorithm.

• VFRICTION: Define contact frictional behavior between surfaces defined with the general contact algorithm.

• VUAMP: Specify amplitudes.

• VUANISOHYPER_INV: Define anisotropic hyperelastic material behavior using the invariant formulation.

• VUANISOHYPER_STRAIN: Define anisotropic hyperelastic material behavior based on Green strain.

• VUEL: Define an element.

• VUFIELD: Specify predefined field variables.

• VUFLUIDEXCH: Define mass/heat energy flow rates for fluid exchange.

• VUFLUIDEXCHEFFAREA: Define effective area for fluid exchange.

• VUHARD: Define the yield surface size and hardening parameters for isotropic plasticity or combined hardening models.

• VUINTER: Define the contact interaction between surfaces defined with the contact pair algorithm.

• VUINTERACTION: Define the contact interaction between surfaces defined with the general contact algorithm.

• VUMAT: Define material behavior.

• VUMULLINS: Define damage variable for the Mullins effect material model.

• VUSDFLD: Redefine field variables at a material point.

• VUTRS: Define a reduced time shift function for a viscoelastic material.

• VUVISCOSITY: Define the shear viscosity for equation of state models.

• VWAVE: Define wave kinematics for an Abaqus/Aqua analysis.

The available user subroutines for Abaqus/CFD are as follows:

• SMACfdUserPressureBC: Specify prescribed pressure boundary conditions.

• SMACfdUserVelocityBC: Specify prescribed velocity boundary conditions.