v0.1 beta · free for Windows

Stop guessing what
DDSDDE means.

An Abaqus UMAT has 37 arguments. Their names tell you nothing about their units, and nothing about which ones you must write to. ddsdde shows all three facts for the argument under your cursor — so the manual stays shut.

Download for Windows See how it works
No Abaqus licence needed No compiler needed Your code never leaves your machine
elastic_umat.f — line 42, column 18
SUBROUTINE UMAT(STRESS,STATEV,DDSDDE,SSE,SPD,SCD, 1 RPL,DDSDDT,DRPLDE,DRPLDT,STRAN,DSTRAN,TIME,DTIME, ┌─ INSPECTOR ────────────────────────────────┐ │ DDSDDE WRITE │ │ │ │ Material Jacobian. │ │ The change in stress divided by the │ │ change in strain. │ │ │ │ Type REAL(NTENS,NTENS) │ │ Units stress (Pa, MPa) │ │ Access You must write this array. │ │ Abaqus does not read it back. │ └────────────────────────────────────────────┘
20Subroutine types, from UMAT to VEXTERNALDB
346Arguments, each with meaning, units and access
19Worked examples, simple through research grade
368Reference pages, searchable and offline
Three facts, instantly

The manual answers this
in twenty minutes.

ddsdde answers it in zero. Put the cursor on an argument and the panel on the right fills in.

1

What it is

The physical quantity, in plain words. DDSDDE is the material Jacobian — the change in stress divided by the change in strain. Not a symbol to memorise.

2

Its units

Abaqus has no unit system, so a wrong unit produces no error. It produces a wrong answer that looks entirely plausible. Every argument carries its dimension.

3

Read or write

Whether Abaqus supplies the value or you must calculate it. This is the most frequent cause of a subroutine that compiles cleanly and returns incorrect results.

Hold Shift and click any argument to open its full reference — type, ordering, sign convention and the mistakes people make with it.

The interface

Three panels. Nothing else.

A file tree, an editor, and the inspector. The top bar carries one control. Everything else lives on a keyboard shortcut, the way you already work.

ddsdde umat_j2.f Abaqus Docs EXPLORER examples/ elastic_umat.f umat_j2.f vumat_neo.f creep_power.f umat_j2.f 42SUBROUTINEUMAT(STRESS,STATEV, 431DDSDDE,SSE,SPD,SCD,RPL,DDSDDT, 44 45C ---- elastic trial stress ---- 46DOK1 = 1, NTENS 47STRIAL(K1) = STRESS(K1) 48END DO UMAT line 42 CURSOR ON Shift+click for docs DDSDDE OUT (NTENS,NTENS) Material Jacobian of the constitutive model. Units: Pa Manual: Abaqus Sub. Ref. 1.1.44 STRESS IN/OUT STATEV IN/OUT DSTRAN IN NTENS IN ddsdde umat_j2.f Fortran 77 Ln 42, Col 18
Put the cursor on an argument and the panel on the right shows what it is, its units, and whether you read it or write it. The green OUT badge on DDSDDE means Abaqus does not supply that value — you must calculate it.
Abaqus Docs ← Search the reference… Follow cursor ⤢ × EXAMPLES All examples Simple · 4 Intermediate · 5 Advanced · 5 Research grade · 5 SUBROUTINES ▾ UMAT Full reference STRESS DDSDDE STATEV ▸ VUMAT ▸ UEL ▸ UHARD FULL REFERENCE UMAT The Jacobian and convergence An incorrect Jacobian changes the convergence rate. It does not change the answer. Slow convergence and repeated cutbacks point at the tangent; a wrong answer points at the stress update. Worked example: integration Δσ = (Δt λ / 2 + λ*) tr(Δε) + … T = Δt / 2 + κ Variables to be defined DDSDDE(NTENS,NTENS) Material Jacobian. You must set this on every call.
Press Ctrl+Shift+D, or Shift-click any argument in the editor. 368 pages: a full reference per subroutine, one page per argument, and 19 worked examples graded from simple to research.
elastic_umat.f 18C reference: elastic 19DDSDDE(K1,K1) = XLAM 20 + 2.0D0*XMU umat_j2.f 96C algorithmic tangent 97EFFG = XMU*(SYIELD 98 + HARD*DEQPL)/SEQ The accent bar marks the pane that has focus. The inspector, the status bar, Ctrl+O and Ctrl+S all follow it. Ctrl+\ split right Ctrl+Shift+\ split down Alt+1 / Alt+2 focus pane
Split right or down, drag the divider to resize, and move the current file across from the command palette.

These figures are drawn from the interface source rather than photographed, so they stay sharp on any display and follow your system light or dark setting.

Coverage

Every argument. Every type.

All 346 arguments carry a description, a unit and an access direction. UMAT has the most depth, because UMAT is the primary target of this release.

Documented subroutine types
TypePurposeArguments
Abaqus/Standard — material behaviour
UMATMechanical constitutive model37COMPLETE
UMATHTHeat transfer constitutive model27COMPLETE
CREEPCreep and swelling law25COMPLETE
UHARDIsotropic hardening law22COMPLETE
USDFLDSolution-dependent field variables25COMPLETE
UEXPANThermal expansion11COMPLETE
UTRSTime-temperature shift10COMPLETE
Abaqus/Standard — elements, loads and utilities
UELUser-defined element25COMPLETE
UELMATUser element with library material21COMPLETE
DLOADDistributed load11COMPLETE
DFLUXDistributed heat flux12COMPLETE
UFIELDPredefined field variables at nodes11COMPLETE
URDFILRead the results file6COMPLETE
UEXTERNALDBExternal database access6COMPLETE
Abaqus/Explicit
VUMATMechanical constitutive model20COMPLETE
VUELUser-defined element24COMPLETE
VDLOADDistributed load11COMPLETE
VDFLUXDistributed heat flux15COMPLETE
VDISPPrescribed boundary motion22COMPLETE
VEXTERNALDBExternal database access5COMPLETE

COMPLETE means every argument carries a description, a unit and an access direction. It does not mean the data is free of errors. Report an incorrect entry and it gets corrected.

Worked examples

From first UMAT
to research grade.

Nineteen real models, ordered so each one prepares you for the next. Every page carries the physics, the code, the input deck, a verification procedure, and the mistakes that cost people weeks.

Simple
  • Isotropic linear elasticity
  • Orthotropic composite ply
  • Field-driven degradation
  • Hydrostatic pressure load
Intermediate
  • J2 plasticity, radial return
  • Johnson-Cook hardening
  • Welding heat transfer
  • Norton-Bailey creep
  • External field histories
Advanced
  • Finite-strain hyperelasticity
  • GTN ductile damage
  • Cohesive zone delamination
  • Finite viscoelasticity
  • Explicit tool control
Research
  • Phase field fracture
  • Hydrogen embrittlement
  • Crystal plasticity
  • Multiscale FE²
  • Co-simulation state

Each example cites the papers and repositories to read. ddsdde summarises them; it does not redistribute their code.

The editor

Fortran, done right.

Built on Monaco — the editor inside Visual Studio Code. If you come from VS Code, your key bindings already work.

Download

Free while in beta.

One installer, no configuration. Nothing to license, nothing to compile, nothing sent to a server.

Download for Windows

Windows may show a SmartScreen message — click More info, then Run anyway. The installer is not code-signed yet.

  • Windows10 / 11 x64 · 15 MB
  • macOSon the roadmap
  • Linuxon the roadmap
  • Abaqus licencenot required
  • Fortran compilernot required
  • Anthropic API keyoptional

Built on Tauri v2. Questions and defect reports go to flm2127@columbia.edu.

Close the manual.

Every argument, every subroutine, every worked example — in the window where you are already writing the code.

Download for Windows Read the docs