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# ABAQUS 2016

USER SUBROUTINES REFERENCE GUIDE

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3DEXPERIENCE

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# Abaqus User Subroutines

Reference Guide

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# Legal Notices

Abaqus, the 3DS logo, and SIMULIA are commercial trademarks or registered trademarks of Dassault Systèmes or its subsidiaries in the United States and/or other countries. Use of any Dassault Systèmes or its subsidiaries trademarks is subject to their express written approval.

Abaqus and this documentation may be used or reproduced only in accordance with the terms of the software license agreement signed by the customer, or, absent such an agreement, the then current software license agreement to which the documentation relates.

This documentation and the software described in this documentation are subject to change without prior notice.

Dassault Systèmes and its subsidiaries shall not be responsible for the consequences of any errors or omissions that may appear in this documentation.

© Dassault Systèmes, 2015

Other company, product, and service names may be trademarks or service marks of their respective owners. For additional information concerning trademarks, copyrights, and licenses, see the Legal Notices in the Abaqus 2016 Installation and Licensing Guide.

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# Preface

This section lists various resources that are available for help with using Abaqus Unified FEA software.

# Support

Both technical software support (for problems with creating a model or performing an analysis) and systems support (for installation, licensing, and hardware-related problems) for Abaqus are offered through a global network of support offices, as well as through our online support system. Contact information for our regional offices is accessible from SIMULIA→Locations at www.3ds.com/simulia. The online support system is accessible by selecting the SUBMIT A REQUEST link at Support - Dassault Systèmes (http://www.3ds.com/support).

# Online support

Dassault Systèmes provides a knowledge base of questions and answers, solutions to questions that we have answered, and guidelines on how to use Abaqus, Engineering Process Composer, Isight, Tosca, fe-safe, and other SIMULIA products. The knowledge base is available by using the Search our Knowledge option on www.3ds.com/support (http://www.3ds.com/support).

By using the online support system, you can also submit new requests for support. All support/service requests are tracked. If you contact us by means outside the system to discuss an existing support problem and you know the support request number, please mention it so that we can query the support system to see what the latest action has been.

# Training

All SIMULIA regional offices offer regularly scheduled public training classes. The courses are offered in a traditional classroom form and via the Web. We also provide training seminars at customer sites. All training classes and seminars include workshops to provide as much practical experience with Abaqus as possible. For a schedule and descriptions of available classes, see the Training link at www.3ds.com/productsservices/simulia (www.3ds.com/products-services/simulia) or call your support office.

# Feedback

We welcome any suggestions for improvements to Abaqus software, the support tool, or documentation. We will ensure that any enhancement requests you make are considered for future releases. If you wish to make a suggestion about the service or products, refer to www.3ds.com/simulia. Complaints should be made by contacting your support office or by visiting SIMULIA→Quality Assurance at www.3ds.com/simulia (www.3ds.com/simulia).

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# Contents

# 1. User Subroutines

# Abaqus/Standard subroutines

CREEP: Define time-dependent, viscoplastic behavior (creep and swelling). 1.1.1

DFLOW: Define nonuniform pore fluid velocity in a consolidation analysis. 1.1.2

DFLUX: Define nonuniform distributed flux in a heat transfer or mass diffusion analysis. 1.1.3

DISP: Specify prescribed boundary conditions. 1.1.4

DLOAD: Specify nonuniform distributed loads. 1.1.5

FILM: Define nonuniform film coefficient and associated sink temperatures for heat transfer analysis. 1.1.6

FLOW: Define nonuniform seepage coefficient and associated sink pore pressure for consolidation analysis. 1.1.7

FRIC: Define frictional behavior for contact surfaces. 1.1.8

FRIC\_COEF: Define the frictional coefficient for contact surfaces. 1.1.9

GAPCON: Define conductance between contact surfaces or nodes in a fully coupled temperature-displacement analysis, coupled thermal-electrical-structural analysis, or pure heat transfer analysis. 1.1.10

GAPELECTR: Define electrical conductance between surfaces in a coupled thermal-electrical or a coupled thermal-electrical-structural analysis. 1.1.11

HARDINI: Define initial equivalent plastic strain and initial backstress tensor. 1.1.12

HETVAL: Provide internal heat generation in heat transfer analysis. 1.1.13

MPC: Define multi-point constraints. 1.1.14

ORIENT: Provide an orientation for defining local material directions or local directions for kinematic coupling constraints or local rigid body directions for inertia relief. 1.1.15

RSURFU: Define a rigid surface. 1.1.16

SDVINI: Define initial solution-dependent state variable fields. 1.1.17

SIGINI: Define an initial stress field. 1.1.18

UAMP: Specify amplitudes. 1.1.19

UANISOHYPER\_INV: Define anisotropic hyperelastic material behavior using the invariant formulation. 1.1.20

UANISOHYPER\_STRAIN: Define anisotropic hyperelastic material behavior based on Green strain. 1.1.21

UCORR: Define cross-correlation properties for random response loading. 1.1.22

UCREEPNETWORK: Define time-dependent behavior (creep) for models defined within the parallel rheological framework. 1.1.23

UDECURRENT: Define nonuniform volume current density in an eddy current or magnetostatic analysis. 1.1.24

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UDEMPOTENTIAL: Define nonuniform magnetic vector potential on a surface in an eddy current or magnetostatic analysis. 1.1.25

UDMGINI: Define the damage initiation criterion. 1.1.26

UDSECURRENT: Define nonuniform surface current density in an eddy current or magnetostatic analysis. 1.1.27

UEL: Define an element. 1.1.28

UELMAT: Define an element with access to materials. 1.1.29

UEXPAN: Define incremental thermal strains. 1.1.30

UEXTERNALDB: Manage user-defined external databases and calculate model-independent history information. 1.1.31

UFIELD: Specify predefined field variables. 1.1.32

UFLUID: Define fluid density and fluid compliance for hydrostatic fluid elements. 1.1.33

UFLUIDCONNECTORLOSS: Define the loss coefficient for fluid flow in fluid pipe connector elements. 1.1.34

UFLUIDCONNECTORVALVE: Define the valve opening to control flow in fluid pipe connector elements. 1.1.35

UFLUIDLEAKOFF: Define the fluid leak-off coefficients for pore pressure cohesive elements. 1.1.36

UFLUIDPIPEFRICTION: Define the frictional coefficient for fluid flow in fluid pipe elements. 1.1.37

UGENS: Define the mechanical behavior of a shell section. 1.1.38

UHARD: Define the yield surface size and hardening parameters for isotropic plasticity or combined hardening models. 1.1.39

UHYPEL: Define a hypoelastic stress-strain relation. 1.1.40

UHYPER: Define a hyperelastic material. 1.1.41

UINTER: Define surface interaction behavior for contact surfaces. 1.1.42

UMASFL: Specify prescribed mass flow rate conditions for a convection/diffusion heat transfer analysis. 1.1.43

UMAT: Define a material’s mechanical behavior. 1.1.44

UMATHT: Define a material’s thermal behavior. 1.1.45

UMESHMOTION: Specify mesh motion constraints during adaptive meshing. 1.1.46

UMOTION: Specify motions during cavity radiation heat transfer analysis or steady-state transport analysis. 1.1.47

UMULLINS: Define damage variable for the Mullins effect material model. 1.1.48

UPOREP: Define initial fluid pore pressure. 1.1.49

UPRESS: Specify prescribed equivalent pressure stress conditions. 1.1.50

UPSD: Define the frequency dependence for random response loading. 1.1.51

URDFIL: Read the results file. 1.1.52

USDFLD: Redefine field variables at a material point. 1.1.53

UTEMP: Specify prescribed temperatures. 1.1.54

UTRACLOAD: Specify nonuniform traction loads. 1.1.55

UTRS: Define a reduced time shift function for a viscoelastic material. 1.1.56

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UTRSNETWORK: Define a reduced time shift function for models defined within the parallel rheological framework. 1.1.57

UVARM: Generate element output. 1.1.58

UWAVE: Define wave kinematics for an analysis. 1.1.59

UXFEMNONLOCALWEIGHT: Define the weight function used to compute the average stress/strain to determine the crack propagation direction. 1.1.60

VOIDRI: Define initial void ratios. 1.1.61

# Abaqus/Explicit subroutines

VDFLUX: Specify nonuniform distributed fluxes in an explicit dynamic coupled temperature-displacement analysis. 1.2.1

VDISP: Specify prescribed boundary conditions. 1.2.2

VDLOAD: Specify nonuniform distributed loads. 1.2.3

VEXTERNALDB: User subroutine that gives control to the user at key moments of the analysis so that data can be exchanged dynamically among user subroutines and with external programs or files. 1.2.4

VFABRIC: Define fabric material behavior. 1.2.5

VFRIC: Define frictional behavior for contact surfaces. 1.2.6

VFRIC\_COEF: Define the frictional coefficient for contact surfaces. 1.2.7

VFRICTION: Define frictional behavior for contact surfaces. 1.2.8

VUAMP: Specify amplitudes. 1.2.9

VUANISOHYPER\_INV: Define anisotropic hyperelastic material behavior using the invariant formulation. 1.2.10

VUANISOHYPER\_STRAIN: Define anisotropic hyperelastic material behavior based on Green strain. 1.2.11

VUCHARLENGTH: Define characteristic element length at a material point. 1.2.12

VUCREEPNETWORK: Define time-dependent behavior (creep) for models defined within the parallel rheological framework. 1.2.13

VUEL: Define an element. 1.2.14

VUEOS: Define equation of state material model. 1.2.15

VUFIELD: Specify predefined field variables. 1.2.16

VUFLUIDEXCH: Define the mass flow rate/heat energy flow rate for fluid exchange. 1.2.17

VUFLUIDEXCHEFFAREA: Define the effective area for fluid exchange. 1.2.18

VUHARD: Define the yield surface size and hardening parameters for isotropic plasticity or combined hardening models. 1.2.19

VUINTER: Define the interaction between contact surfaces. 1.2.20

VUINTERACTION: Define the contact interaction between surfaces with the general contact algorithm. 1.2.21

VUMAT: Define material behavior. 1.2.22

VUMULLINS: Define damage variable for the Mullins effect material model. 1.2.23

VUSDFLD: Redefine field variables at a material point. 1.2.24

VUTRS: Define a reduced time shift function for a viscoelastic material. 1.2.25

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VUVISCOSITY: Define the shear viscosity for equation of state models. 1.2.26

VWAVE: Define wave kinematics for an analysis. 1.2.27

# Abaqus/CFD subroutines

SMACfdUserPressureBC: Specify prescribed pressure boundary conditions. 1.3.1

SMACfdUserVelocityBC: Specify prescribed velocity boundary conditions. 1.3.2

# 2. Utility Routines

Obtaining Abaqus environment variables 2.1.1

Obtaining the Abaqus job name 2.1.2

Obtaining the Abaqus output directory name 2.1.3

Obtaining parallel processes information 2.1.4

Obtaining part information 2.1.5

Obtaining material point information in an Abaqus/Standard analysis 2.1.6

Obtaining material point information in an Abaqus/Explicit analysis 2.1.7

Obtaining material point information averaged at a node 2.1.8

Obtaining node point information 2.1.9

Obtaining node to element connectivity 2.1.10

Obtaining stress invariants, principal stress/strain values and directions, and rotating tensors in an Abaqus/Standard analysis 2.1.11

Obtaining principal stress/strain values and directions in an Abaqus/Explicit analysis 2.1.12

Obtaining wave kinematic data in an Abaqus/Aqua analysis 2.1.13

Printing messages to the message or status file 2.1.14

Terminating an analysis 2.1.15

Obtaining sensor information 2.1.16

Accessing Abaqus materials 2.1.17

Accessing Abaqus thermal materials 2.1.18

Obtaining scalar state information in an Abaqus/CFD analysis 2.1.19

Obtaining vector state information in an Abaqus/CFD analysis 2.1.20

Obtaining the MPI communicator in an Abaqus/CFD analysis 2.1.21

Ensuring thread safety 2.1.22

Allocatable arrays 2.1.23

# A. Index

User subroutines index A.1

User subroutine functions listing A.2
