April 2026

The release notes for the upcoming release are:

New features

Elements
Initial conditions:
- Fluctuating fields with multiple correlation lengths
Loads:
- Renamed all springs to spring-ground-*
- Added springs acting in global x-, y-, z-directions for beam elements and 3D elements
Constitutive models
- Hardening Soil: The Hardening Soil model with Matsuoka-Nakai failure surface with benchmarks given in the Benchmark Manual.
- hypo-ISA-SF | Hypoplastic model for sand according to von Wollfersdorff (1996)¹ with intergranular strain anisotropy (ISA) and semi-fluidized state (SF) extension (Tafili et al., 2024)² with benchmarks given in the Benchmark Manual.

Performance
- Performance of the PARDISO solver was noticeably improved, reducing solve time by up to a factor of 3.
Constitutive models
- Barotropic elasticity was modified such that for void ratios smaller than \(e<10^{-3}\) the pyknotropy feature is deactivated
Output
- Stress and Strain output are now requested via stress and strain, respectively. The old keywords S and E are deprecated (backward compatibility is maintained).
- More detailed information for cutback reasons during automatic time stepping reported in statistic (.sta) and message (.msg) files

Resolved bug for *Equations where the coupling terms between two constrained degrees of freedom are inactive in the model
Resolved bug for hypoplastic/Sanisand contact models.
Linux versions: import of random fields from csv-files fixed

Benchmark Manual
- Hardening Soil with Matsuoka-Nakai failure surface
Reference Manual
- Improved documentation of the barotropic elasticity
Theory Manual
- Hardening Soil with Matsuoka-Nakai failure surface
- Barotropic elasticity
Tutorial Manual
- Corrected erroneous material definition in the tutorials on oedometric compression, drained mon. triaxial test, undrained mon. triaxial test and undrained cyclic triaxial test
- User defined extensions: Added a note regarding thread-safety requirements and the necessity of stack allocation for local variables.

P.-A. Wolffersdorff. A hypoplastic relation for granular materials with a predefined limit state surface. Mechanics of Cohesive-frictional Materials, 1(3):251–271, 1996. doi:10.1002/(SICI)1099-1484(199607)1:3<251::AID-CFM13>3.0.CO;2-3. ↩
Merita Tafili, Jose Duque, David Mašín, and Torsten Wichtmann. A hypoplastic model for pre-and post-liquefaction analysis of sands. Computers and Geotechnics, 171:106314, 2024. ↩