ANSYS UPFs

Customize and extend the features of Mechanical APDL Solver

Development of ANSYS Routines in Fortran or C++

With help of ANSYS User Programmable Features (UPFs) we can extended and customize the standard features of ANSYS Mechanical APDL solver (MAPDL solver). This allows us to write routines or subroutines in C, C++ or even in Fortran and use them for your user-specific simulation tasks, for instance.

To sum up, UPFs allow us to customize the ANSYS Mechanical APDL solver to your needs, which may be a user-defined material law option, your own element type, or custom failure criterion for layered elements (composites).

Using ANSYS UPFs we have developed user-defined material model for Steel Fibre Reinforced Concrete (SFRC).

Applications

Predefined subroutines for customization of MAPDL solver can be used for definition of:

your own element types (user-defined element type USER300 with subroutine UserElem)
material models with user-defined plasticity, damage or softening material laws (subroutine UserMat)
your own thermal material models (subroutine UserMatTh)
material models with user- defined hyperelasticity laws (subroutines UserHyper, UserHyperAniso)
custom creep material behavior (subroutine UserCreep)
your own cohesive zone material (subroutine userCZM)
custom routines for user-defined contact interfacial behaviors (subroutine usercnprop for your own contact properties, subroutine userfric for writing your own friction laws, subroutine userinter for your own contact interactions, subroutine userwear for your own wear law)
user-defined real constants and thicknesses
your own failure criteria (subroutine userfc)

Frequently asked questions

These are the questions engineers ask most often before starting a UPF development project: whether standard ANSYS models can be extended without solver-level intervention, what validation looks like in practice, and how UPF work differs from ACT or APDL. Answered directly, without sales language.

What are ANSYS UPFs and when do I need them?

Typically a client comes to us when standard ANSYS material models produce results that don’t match the actual material behaviour — and standard calibration isn’t sufficient.

UPFs (User Programmable Features) are the deepest level of ANSYS customisation — they allow the behaviour of the ANSYS MAPDL solver itself to be modified. You need them when standard material models, element types, or failure criteria in ANSYS don’t cover the specific behaviour of your material or structure.

What we do:

Develop custom material models — plasticity, damage, hyperelasticity, creep, cohesive zones, contact properties
Implement custom element types or failure criteria for layered structures and composites
Calibrate and validate models on experimental data — a result without validation has no practical value

This makes sense when:

You need results that will stand up in certification proceedings or Prüfstatiker review

Standard ANSYS material models produce results that don’t match the actual behaviour of your material

You’re working with specific materials — special alloys, composites, rubbers, fibre-reinforced concrete

What specifically can be implemented using UPFs?

UPFs cover a wide range of solver-level customisations.

What we most commonly do:

Custom constitutive material models — you define precisely how your material behaves under loading
Custom failure criteria for composite or layered structures
Custom element types for specific physical problems
Custom contact formulations for special tribological or adhesive problems

Example from practice:

We developed a custom material model for steel fibre-reinforced concrete structures (SFRC) — implemented, calibrated, and validated on experimental data. See our Reference Projects

In which programming languages do you develop UPFs?

We work in C, C++, and Fortran — the languages required by the ANSYS MAPDL solver for UPFs.

What this means for your projects:

If your case doesn’t require intervention at solver level, consider ANSYS ACT Apps or APDL Scripts — they are faster and less costly

UPF development demands a high combination of expertise in numerical methods, mechanics, and low-level programming — our team brings both together

How is a custom material model validated?

Validation is a mandatory part of every UPF development — without it, a custom material model has neither practical nor certification value.

What we do:

Compare UPF model results with experimental data or reference calculations
Conduct sensitivity analyses — how results change with variations in material parameters
Document the entire calibration and validation process in a technical report

What this means for you:

The resulting model is credible, documented, and usable for engineering decisions or certification processes. If you don’t have experimental data available, we can propose a calibration approach from available inputs.

Is UPF development suitable for research or academic projects?

Yes — developing custom material models is an area where industrial practice and research naturally meet.

What we do:

We work with both industrial customers and research projects requiring implementation of advanced constitutive models
We bridge academic insights and practical implementation in ANSYS — from equations through code to validation

Benefit for your project:

A research model implemented in ANSYS is applicable to real engineering problems — not just publications
More about our research activities in the R&D Projects section

A brief description of the problem is enough — we’ll tell you how to proceed. If it doesn’t make sense to address it, we’ll tell you directly.