Hexagon is excited to announce the release of Marc 2025.1, which offers significant enhancements from previous versions. Mentat has an improved user experience, the previous analysis state (also called pre state) has more capabilities, the hybrid contact formulation is updated, and we introduced a new subroutine for user-defined materials.

Release highlights
Key highlights of Marc 2025.1 include:

Hybrid contact formulation updates 
The recommended hybrid node-to-segment contact algorithm introduced in earlier releases is now set as the default for all new models for structural analysis (static or dynamic). This approach activates a double-sided contact formulation that primarily uses penalty-based enforcement, significantly reducing the need to manually distinguish between primary and secondary bodies. Compared to the previous node-to-segment method, users can expect improved accuracy, performance and robustness in most scenarios, along with reduced need to fine-tune contact parameters to achieve successful simulations.

The hybrid approach supports now also the use of nodes on geometric contact bodies – a capability not available for other contact algorithms. This modelling flexibility is particularly beneficial for simulations involving manufacturing processes.

 A new user material subroutine called UMATERIAL 

The HYPELA2 subroutine in Marc has long provided a way to define user materials when built-in models were insufficient for capturing complex mechanical behaviour. However, its use was often cumbersome, with limited documentation and few practical examples. In the 2025.1 release, Marc introduces a new and improved subroutine for user-defined materials called UMATERIAL, designed to offer a more accessible, flexible, and user-friendly experience.
With this new capability, engineers will:

• Benefit from a clearer and more intuitive user interface compared to HYPELA2
• Gain better control over near-incompressible and incompressible materials
• Choose from predefined nonlinear integration schemes
• Implement rheological multi-network models more naturally
• Focus on defining the deviatoric behaviour while Marc automatically handles the volumetric (bulk) response
• Access a set of utility routines designed to accelerate the development of custom material models

The overall user experience for defining custom materials is significantly enhanced. To get users started quickly, two practical examples are included in the user guide: a rubber-like material model and a material model incorporating metal plasticity. These examples serve as helpful references for efficiently developing and implementing a user-defined material behaviour.