UMAT-ABAQUS | A general framework to develop material models (UMAT) in ABAQUS (Dassault Systèmes)

This library provides subroutines for 3D implementation of large deformation constitutive behavior using continuum mechanics. The code is written in either fixed-form or modern Fortran. You can use it as a primary subroutine interface for ABAQUS (Dassault Systèmes) as a UMAT or an interface for your finite element code. I have used this code to model many specific material laws of biological soft tissues and cells. Take a look at the reference list.

This repository is oriented for experienced researchers in biomechanics and continuum mechanics. You are highly welcome to use these open-resource codes for your non-commercial usage; please cite the below papers.

The core routines for the subroutine interface are:

!main program - subroutines caller

program main


!uexternaldb subroutine - read databases of microstructure 
!            information, passes in as common data blocks

      SUBROUTINE UEXTERNALDB(LOP,LRESTART,TIME,DTIME,KSTEP,KINC)


!main subroutine - calculates stress and material tangent

      SUBROUTINE UMAT(STRESS,STATEV,DDSDDE,SSE,SPD,SCD,
     1 RPL,DDSDDT,DRPLDE,DRPLDT,
     2 STRAN,DSTRAN,TIME,DTIME,TEMP,DTEMP,PREDEF,DPRED,CMNAME,
     3 NDI,NSHR,NTENS,NSTATEV,PROPS,NPROPS,COORDS,DROT,PNEWDT,
     4 CELENT,DFGRD0,DFGRD1,NOEL,NPT,LAYER,KSPT,KSTEP,KINC)

This library does not run any specific example. See my other repositories for more models.

├── src
├── sym
└── test_in_abaqus

3 directories

• src - files to build your UMAT file.
• sym - examples of analytical derivations of the constitutive relations
• test_in_abaqus - example to test the UMAT file in abaqus environment

Simple bash scripts are provided for building UMAT-ABAQUS with gfortran. The code can also be compiled with the Intel Fortran Compiler (and presumably any other Fortran compiler that supports modern standards).

• build.sh - this script concatenates fortran files into one umat file and compiles the test program. since you can interact with abaqus using only one fortran file, this script also copies the concatenated file to the test_in_abaqus dir
• run_code.sh simple input-output test for an arbitrary deformation gradient

jpsferreira.github.io/UMAT-ABAQUS/

• João P S Ferreira

• 2020/09/07.

• GNU GPL 3.0.

J P S Ferreira et al. "On the mechanical response of the actomyosin cortex during cell indentations". English. In: Biomechanics and Modeling in Mechanobiology 130.10 (Apr. 2020), pp. 202–19. doi: (10.1007/s10237-020-01324-5).

J P S Ferreira et al. "Altered mechanics of vaginal smooth muscle cells due to the lysyl oxidase-like1 knockout." English. In: Acta Biomaterialia (Apr. 2020). doi: (10.1016/j.actbio.2020.03.046).

J A López-Campos et al. "Characterization of hyperelastic and damage behavior of tendons." English. In: Computer Methods in Biomechanics and Biomedical Engineering 81.2 (Jan. 2020), pp. 1–11. doi: (10.1080/10255842.2019.1710742).

M C P Vila Pouca et al. "Viscous effects in pelvic floor muscles during childbirth: A numerical study." English. In: International Journal for Numerical Methods in Biomedical Engineering 34.3 (Mar. 2018), e2927. doi: (10.1002/cnm.2927).

J P S Ferreira, M P L Parente, and R M Natal Jorge. "Continuum mechanical model for cross-linked actin networks with contractile bundles". English. In: Journal of the Mechanics and Physics of Solids (2017). doi: (10.1016/j.jmps.2017.09.009).

J P S Ferreira et al. "A general framework for the numerical implementation of anisotropic hyperelastic material models including non-local damage". In: Biomechanics and Modeling in Mechanobiology 44.18–19 (2017), pp. 5894–1140. doi: (10.1007/s10237-017- 0875-9).