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.

• Anderson acceleration: Anderson acceleration is a general technique for accelerating the convergence of fixed-point iterations (i.e. when the global Jacobian used in the Newton-Raphson iteration is not updated at every iteration or changes only mildly - for instance when an elastic tangent is used in place of the consistent elasto-plastic tangent). For more information please refer to the Refernce and the Theory manuals.

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General modifications

• 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

• Accelerator: New keyword *Accelerator which gives a unified interface so methods desinged to improve convergence of the iterative solution process (implicit simulations). The new keyword replaces the old *Line search, however, backward compatibility is maintained. See the Refernce and the Theory manuals for more information.

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Resolved bugs

• 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

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Manuals

• 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.

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1. 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. ↩

2. 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. ↩