Dear all,
I am currently using the TRM module to run a coupled thermo-hydro-mechanical simulation of a pile embedded in soil. The soil is modeled using a custom constitutive model implemented in MFront.
In the simulation, a mechanical load is first applied to the pile, followed by a heating phase, and then a reloading phase. The issue arises during this reloading step, which occurs much later in the simulation timeline. At that point, the simulation unexpectedly stops and returns the following error:
I would appreciate any advice or suggestions on what might be causing this issue.
Best regards,
María
Hi María,
the MFront integration failed for some element. I don’t yet understand why the time stepper is not reducing the time step size. Can you post the log as text here or via mail?
And which version of OGS is it? (Would be in the log as well.)
– d
Hi Dmitri,
Thank you for your response.
I believe the time step is indeed being reduced, but I found it strange that the convergence criterion values by component are not shown — only the divergence is reported. Could this be indicative of a different type of error?
I tried modifying one of the parameters in the soil’s constitutive model, and the simulation now runs until the end. However, I still frequently encounter convergence issues, and I’m not entirely sure how to resolve them. If you have any suggestions or recommendations, I would really appreciate it.
For reference, I’m using the following OGS version:
OpenGeoSys-6 version 6.4.4-3156-g79790639.dirty
Below is the final part of the log file, where the error occurs:
debug: Stats [J]: 730944 elements added to the global matrix.
error: Abort nonlinear iteration. Repeating timestep. Reason: Error in process’ assembly: MFront: integration failed with status -1.
info: [time] Solving process #0 took 3.8803 s in time step #506
error: The nonlinear solver failed in time step #506 at t = 295577 s for process #0.
info: [time] Time step #506 took 3.88149 s.
warning: Time step will be rejected due to nonlinear solver divergence.
critical: /home/maria/Desktop/OgsPardiso/bgetec-bentonite/ProcessLib/TimeLoop.cpp:394 computeTimeStepping()
warning: Property is not used: ‘property ‘thermal_conductivity’ defined for medium 8’
debug: Property is used: ‘property ‘relative_permeability’ defined for medium 8’
debug: Property is used: ‘property ‘porosity’ defined for medium 8’
debug: Property is used: ‘property ‘permeability’ defined for medium 8’
debug: Property is used: ‘property ‘bishops_effective_stress’ defined for medium 8’
debug: Property is used: ‘property ‘biot_coefficient’ defined for medium 8’
debug: Property is used: ‘property ‘viscosity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘Solid’’
warning: Property is not used: ‘property ‘thermal_conductivity’ defined for medium 7’
debug: Property is used: ‘property ‘relative_permeability’ defined for medium 7’
debug: Property is used: ‘property ‘porosity’ defined for medium 7’
debug: Property is used: ‘property ‘permeability’ defined for medium 7’
debug: Property is used: ‘property ‘bishops_effective_stress’ defined for medium 7’
debug: Property is used: ‘property ‘biot_coefficient’ defined for medium 7’
debug: Property is used: ‘property ‘viscosity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘Solid’’
warning: Property is not used: ‘property ‘thermal_conductivity’ defined for medium 6’
debug: Property is used: ‘property ‘relative_permeability’ defined for medium 6’
debug: Property is used: ‘property ‘porosity’ defined for medium 6’
debug: Property is used: ‘property ‘permeability’ defined for medium 6’
debug: Property is used: ‘property ‘bishops_effective_stress’ defined for medium 6’
debug: Property is used: ‘property ‘biot_coefficient’ defined for medium 6’
debug: Property is used: ‘property ‘viscosity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘Solid’’
warning: Property is not used: ‘property ‘thermal_conductivity’ defined for medium 5’
debug: Property is used: ‘property ‘relative_permeability’ defined for medium 5’
debug: Property is used: ‘property ‘porosity’ defined for medium 5’
debug: Property is used: ‘property ‘permeability’ defined for medium 5’
debug: Property is used: ‘property ‘bishops_effective_stress’ defined for medium 5’
debug: Property is used: ‘property ‘biot_coefficient’ defined for medium 5’
debug: Property is used: ‘property ‘viscosity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘Solid’’
warning: Property is not used: ‘property ‘thermal_conductivity’ defined for medium 4’
debug: Property is used: ‘property ‘relative_permeability’ defined for medium 4’
debug: Property is used: ‘property ‘porosity’ defined for medium 4’
debug: Property is used: ‘property ‘permeability’ defined for medium 4’
debug: Property is used: ‘property ‘bishops_effective_stress’ defined for medium 4’
debug: Property is used: ‘property ‘biot_coefficient’ defined for medium 4’
debug: Property is used: ‘property ‘viscosity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘Solid’’
warning: Property is not used: ‘property ‘thermal_conductivity’ defined for medium 3’
debug: Property is used: ‘property ‘relative_permeability’ defined for medium 3’
debug: Property is used: ‘property ‘porosity’ defined for medium 3’
debug: Property is used: ‘property ‘permeability’ defined for medium 3’
debug: Property is used: ‘property ‘bishops_effective_stress’ defined for medium 3’
debug: Property is used: ‘property ‘biot_coefficient’ defined for medium 3’
debug: Property is used: ‘property ‘viscosity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘Solid’’
warning: Property is not used: ‘property ‘thermal_conductivity’ defined for medium 2’
debug: Property is used: ‘property ‘relative_permeability’ defined for medium 2’
debug: Property is used: ‘property ‘porosity’ defined for medium 2’
debug: Property is used: ‘property ‘permeability’ defined for medium 2’
debug: Property is used: ‘property ‘bishops_effective_stress’ defined for medium 2’
debug: Property is used: ‘property ‘biot_coefficient’ defined for medium 2’
debug: Property is used: ‘property ‘viscosity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘Solid’’
warning: Property is not used: ‘property ‘thermal_conductivity’ defined for medium 1’
debug: Property is used: ‘property ‘relative_permeability’ defined for medium 1’
debug: Property is used: ‘property ‘porosity’ defined for medium 1’
debug: Property is used: ‘property ‘permeability’ defined for medium 1’
debug: Property is used: ‘property ‘bishops_effective_stress’ defined for medium 1’
debug: Property is used: ‘property ‘biot_coefficient’ defined for medium 1’
debug: Property is used: ‘property ‘viscosity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘Solid’’
warning: Property is not used: ‘property ‘thermal_conductivity’ defined for medium 0’
debug: Property is used: ‘property ‘relative_permeability’ defined for medium 0’
debug: Property is used: ‘property ‘porosity’ defined for medium 0’
debug: Property is used: ‘property ‘permeability’ defined for medium 0’
debug: Property is used: ‘property ‘bishops_effective_stress’ defined for medium 0’
debug: Property is used: ‘property ‘biot_coefficient’ defined for medium 0’
debug: Property is used: ‘property ‘viscosity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘AqueousLiquid’’
debug: Property is used: ‘property ‘thermal_expansivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘thermal_conductivity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘specific_heat_capacity’ defined for phase ‘Solid’’
debug: Property is used: ‘property ‘density’ defined for phase ‘Solid’’
error: The new step size of 1e-07 is the same as that of the previous rejected time step.
Please re-run ogs with a proper adjustment in the numerical settings,
e.g those for time stepper, local or global non-linear solver.
info: OGS terminated on 2025-08-01 01:22:01+0200.
error: OGS terminated with error.
Thanks again for your help.
Best regards,
María
Hi María @maripicod,
I recently worked with the TRM process and encountered similar convergence issues, although not specifically due to MFront integration, the nonlinear solver often diverged. From my experience, the strong coupling in TRM makes the system particularly sensitive to nonlinearities, especially when material properties differ sharply between regions. In my case, a sudden change in Young’s modulus across material interfaces significantly affected convergence.
Since modifying a constitutive parameter helped your simulation run further, it does point to the material model being a major contributor. If your model contains multiple materials, IDs recommend introducing a smooth transition between properties, for example, using if conditions to avoid abrupt jumps in stiffness or strength.
Regarding the MFront integration failure during reloading, this typically means that the material model couldn’t compute a valid solution for stress or internal variables at a Gauss point. This can happen due to:
- invalid or incompatible state variables during reloading,
- overly large strain increments right after reloading
- or a breakdown in the local Newton solver inside MFront (e.g., stress states outside the valid range).
To reduce the chance of such integration failures, I highly recommend enabling adaptive time stepping (if you haven’t already). A more conservative time step control after reloading can help avoid large strain jumps that might trigger non-physical responses from the material model.
I hope this helps.
Best,
Pavan
Might be not directly related, but I think worth checking out. We just merged a bugfix for the IterationBasedTimeStepper (Fix bugs and add tests for IterationNumberBasedTimeStepping (!5383) · Merge requests · ogs / ogs · GitLab).
@maripicod If the problem is still not resolved, attach the complete log file here (or mail)—the last 100 lines or so don’t have enough clues.
– d
