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Release notes (Engine)

Changes in 9.1.0 (2024-11-28)

  • Extended from maximum 9 to 99 state and dump files (parameter N_res in *OUTPUT).
  • New command, *CFD_STRUCTURE_INTERACTION, for added flexibility when defining coupling between CFD and Finite Elements.
  • New material model, *MAT_POWDER_BURN_POROUS, for fine-grain propellant powder.
  • New command, *INITIAL_FACE_DATA, for defining element face variables. These variables can be used to define loads in commands such as *LOAD_THERMAL_SURFACE.
  • New material model, *MAT_EXPLOSIVE_JWL, for explosives using JWL parameters and programmed burn.
  • New command, *DETONATION, for programmed burn detonation path calculation.
  • Bug fix in CFD solver. Temperature calculations were not correct, if mixing gases with different heat capacities.

Changes in 9.0.2 (2024-10-28)

  • Bug fix in the VAA tool. The presentation of local hit layer thicknesses was sometimes incorrect.
  • Energy balance bug fix in the CFD/FE coupling.
  • Improved accuracy of energy flux in *CFD_SOURCE implementation.
  • Bug fix in CPU implementation of *PROP_DAMAGE_HC. The strain rate sensitivity was not handled correctly.
  • Added support for rebar elements in the command *ACTIVATE_ELEMENTS.
  • Bug fix in GPU version of *MAT_HSS. Rate effects were not accounted for in heating caused by plastic work.
  • New command *CFD_STATE.
  • Implemented Surface SPH support for symmetry planes (limited to global XYZ planes).

Changes in 9.0.1 (2024-10-07)

  • Minor bugfix to the command *GENERATE_PARTICLE_DISTRIBUTION. Some particles were incorrectly positioned outside the domain to be filled.

Changes in 9.0.0 (2024-10-04)

  • Added support for GPU-acceleration in the vulnerable area assessment tool (*VAA). Up to 30x speed-up. Simulations can now be terminated before all frames have been completed.
  • CUDA interface for user materials, allowing for utilization of GPU speed-up.
  • New material model (*MAT_EXPLOSIVE_INITIATION) for simulating the detonation of explosive materials.
  • Added support for reading pre-defined SPH particle distributions. Graded SPH particle distributions can be generated with the new command *GENERATE_PARTICLE_DISTRIBUTION.
  • *LOAD_SURFACE_SMOOTHING, a new command for stabilizing contact interfaces exposed to extreme pressures and inertia effects.
  • *LOAD_ELEMENT_SMOOTHING, a command to mitigate spurious oscillations in higher order elements in strongly dynamic events.
  • A new, fully 2nd order, advection scheme has been added to the CFD solver. Main objective is to improve the accuracy in close range blast loading events.
  • Various bug fixes.
  • Added support for Gruneisen EOS in *MAT_HSS.
  • Unified the version numbering. From version 9.0.0, there will no longer be different version numbers between the Engine and the GUI. We have adopted the common major.minor.patch version scheme. As a general rule, new functionality will come in the minor versions (for instance 9.1.0). If critical bugs are found that require an immediate fix, we will issue patch releases as soon as the bug is fixed and the software tested (for instance 9.0.1). Major releases, where the major version number is incremented are more seldom and only when there are significant changes or updates.

Changes in 8.1.770 (2024-06-04)

  • Critical bug fix in *LOAD_UNDEX. The computed reflected pressure was not correct.
  • *LOAD_EM_CABLE, a new command for electromagnetic forces between conductors.
  • Added support for Nobel-Abel co-volume parameter in *CFD_GAS and in *MAT_PROPELLANT_BURN.
  • Various bug fixes.
  • Added Linux support for user material model.
  • User material models now supports coupling with *PROP_THERMAL and *PROP_DAMAGE_[X].

Changes in 8.1.735 (2024-03-19)

  • Bug fix related to special combinations of *REFINE and *MERGE_DUPLICATED_NODES.
  • Bug fix in treatment of multiple *INITIAL_STATE_HAZ commands.
  • Rebar slip bug fix.
  • Changes to user material model interface.

Changes in 8.1.726 (2024-03-12)

  • Minor update of CFD-FE and CFD-SPH coupling algorithms, for reduced CFD grid direction effects.
  • Improved accuracy of released energy when using *CFD_HE.
  • *FRAGMENT_CLEANUP, a new command for removal of small (irrelevant) fragments at a given time.
  • Bug fix in CFD solver. Explosive state variables were not properly exported to impetus_state_cfdX.bin. The error was introduced in v8.1.674.
  • *PETRIFY bug fix. The time step size was sometimes set to 0.
  • Added rudimentary support for overwriting particles settings in impetus_state_particleX.bin.

Changes in 8.1.700 (2024-02-14)

  • Minor bug fix in the CFD solver, related to the treatment of expanding detonation products.
  • Unit system bug fix in *LOAD_THERMAL_RADIATION.
  • Bug fix in *INCLUDE command, related to local paths with blank spaces.

Changes in 8.1.693 (2024-02-01)

  • Fixed a numerical issue in the CFD solver, related to having a negative A or B parameter in the JWL EOS (e.g. ANFO).
  • Fixed issue concerning "resume" functionality when using Objects with embedded Python scripts.
  • Allow for bolt/nut mismatch in command *PRESTRESS_BOLT.
  • Minor bug fixes.

Changes in 8.1.674 (2024-01-22)

  • Added support for an arbitrary number of different explosive materials inside a CFD domain.

Changes in 8.1.666 (2023-11-24)

  • Bug fixes to CFD-SPH coupling.
  • Added support for SPH-to-SPH in *MERGE.
  • Significant speed-up of *INITIAL_STATE_HAZ initialization process.
  • Added support for prescribed pressure loads on SPH surfaces (*LOAD_PRESSURE).
  • Bug fix and general improvement of SPH-to-FE *MERGE.
  • Added CFD-to-SOIL (discrete particle) coupling. The coupling is automatically activated if soil particles are embedded in the CFD grid.
  • General improvement of the CFD solver, aiming at reducing mesh bias effects in air blast simulations at small stand-off distances.
  • Bug fix to the *VAA tool. The impact angle was sometimes incorrectly computed when working with tetrahedron elements.
  • Node splitting crack area is now computed and written to part.out.

Changes in 8.1.603 (2023-09-28)

  • Minor updates to impetus.info.

Changes in 8.1.600 (2023-09-14)

  • *PARTICLE_SPH: Implemented algorithm for SPH surface calculation, allowing for improved visualization in GUI and for CFD-SPH coupling.
  • *PARTICLE_SPH_JET: Significantly improved jet correction algorithm.
  • *CFD_SOURCE: New command for modeling gas sources.
  • *CFD_HE: Improved accuracy of explosive mass in coarse CFD grids.
  • *CFD_DETONATION: Added support for non-radial detonation paths.
  • *COMPONENT_REBAR: Connectivity bug fix (related to combination of *COMPONENT_REBAR and *ELEMENT_REBAR).
  • *INITIAL_STATE_HAZ: New option, allowing the weld line to be defined as a *PATH.
  • *BC_SYMMETRY: Added support for rebar elements.
  • *BOLT_FAILURE: New command for specifying bolt failure. The command also keeps track of bolt shear and tensile forces.

Changes in 8.0.527 (2023-07-21)

  • *MERGE: Node splitting bug fix.
  • *OUTPUT_SECTION: Bug fix; "ALL" option did not work.
  • *MAT_MMC_OST: Implemented for SPH.
  • *FUNCTION: Added intrinsic function for sensor surface pressure "sps(ID)".
  • *PARTICLE_SPH: Bug fix in elastic energy calculation (bookkeeping).
  • *CFD_DOMAIN: Improved implementation of non-reflective BC.
  • *PARTICLE_DOMAIN: Bug fix in state file output (impetus_state_particleX.bin). SPH pressure was corrupted when having both SPH and discrete particles in the state file.

Changes in 8.0.497 (2023-06-16)

  • *PRESTRESS_BOLT: Added support for headless bolts (pin merged to a plate).
  • *MERGE: Various updates and improvements to penalty based method. Added merge projection displacements to the file "_node_merge_project.k". The information in this file can be used to adjust the mesh and close gaps in the merge interface.
  • *MERGE_DUPLICATED_NODES: Added output to "impetus.info" and fixed an *INCLUDE offset bug.
  • *REFINE: Pentahedron element bug fix.
  • *PROP_DAMAGE_CL_0_45_90: Modified implementation to account for full stress tensor (not only membrane stresses).
  • *MAT_POWDER_BURN: Added coupling to CFD solver.
  • *PROP_DAMAGE_[TYPE]: Added (optional) user defined damage increment for secondary cracking when using node splitting. By default, a second crack is formed at damage D=2.
  • *CFD_DOMAIN: Added support for CFD/SPH coupling.
  • *CFD_HE: Added several built-in calibrations and added support for afterburn effects in USER defined explosives.
  • *CONNECTOR_SPRING: Added spring data to state file "impetus_state_springX.k".
  • *CFD_DOMAIN: Improved implementation and reduced mesh bias effects near the detonation point.
  • *CFD_DOMAIN: Support for complex detonation paths and deactivation time option.
  • *TIME: Added function (fcn) support for dt_max.
  • *OUTPUT_SENSOR: Lagrangian CFD option (makes sensors behave like tracer particles).
  • *PARTICLE_DOMAIN: Restart (state file) bug fix.
  • *CONTACT: Wear calculation bug fix.
  • *OUTPUT_DEBUG: New command to help the debugging of command files.
  • *EROSION_CRITERION: Added effective plastic strain as erosion criterion.
  • *INITIAL_MATERIAL_DIRECTION_[TYPE]: Updates for a better handling of components that are meshed with multiple elements in thickness direction.
  • Updated the embedded Python library to version 3.10 (Linux).

Changes in 8.0.374 (2023-03-15)

  • *CFD_HE: Bug fix (user defined explosives in unit systems other than SI were handled incorrectly).
  • *PARTICLE_SPH_JET: Bug fix (parts of the jet could suddenly disappear).
  • *FREQUENCY_CUTOFF: Bug fix in handling of rigid bodies.
  • *VAA: Improved edge detection algorithm.
  • *PARTICLE_DOMAIN: Bug fix in initial particle distribution (some regions were not always properly filled with particles).

Changes in 8.0.368 (2023-02-27)

  • *PARTICLE_SPH: Improved SPH particle filling scheme.
  • *PARTICLE_SPH_JET: Improved calculation of jet data.
  • *LOAD_AIR_BLAST: Blast wave arrival time bug fix.
  • *MERGE: Improved ability to handle complex geometries with symmetric and cyclic dependencies.
  • *VULNERABLE_AREA_ASSESSMENT: Bug fix in handling of angle dependency and multiple layers.
  • *PARTICLE_DOMAIN: Improved restart functionality. It is now possible to import multiple state files (impetus_state_particleX.bin). We also output more restart sub-domain data to impetus.info.
  • *GEOMETRY_PIPE: Added support for pipe sectors.
  • *PARTICLE_SPH: Internal energies for each individual sub-domain are now calculated and output to particle_sub_domain.out.
  • *CONNECTOR_SPRING: Added variables (to be used in *FUNCTION) for min/max elongation (dnorm_min/dnorm_max).
  • *MAT_FABRIC_ISOTROPIC: A new, easy-to-use, model for fabric materials.
  • A new CFD solver for blast loading (included in Impetus DEFENSE). The corresponding commands are *CFD_DOMAIN, *CFD_GAS, *CFD_HE and *CFD_DETONATION.
  • *PARTICLE_DOMAIN: Improved particle filling algorithm. Bug fix in GPU based particle-structure contact algorithm.
  • *PARTICLE_SPH: General improvement of accuracy and ability to handle the interaction between materials with significantly different density and stiffness.
  • *VAA: Reworked vulnerable area assessment tool, with more robust and efficient treatment of edge effects.

Changes in 7.0.282 (2022-11-30)

  • *GEOMETRY_ELLIPSOID: New geometry type.
  • Bug fix in intrinsic function for maximum part damage (dmgp).
  • *LOAD_AIR_BLAST: Improved calculation of blast wave arrival time.
  • *OUTPUT_DAMAGE_MAP: Bug fix. Mapping domain coordinates were sometimes mixed up.

Changes in 7.0.280 (2022-11-25)

  • *PARTICLE_HE: Reduced time step during detonation phase for increased accuracy.
  • *PARTICLE_SPH: Improved accuracy of sliding contact (SPH to SPH).

Changes in 7.0.252 (2022-11-10)

  • Updated the embedded Python library to version 3.10 (Windows only).
  • GPU: if enabled, ECC information is now written to gpu.info.
  • *PARTICLE_DOMAIN_CLEANUP: Added more cleanup criteria (mass, kinetic energy and velocity).
  • *MERGE: Bug fix in treatment of SPH nodes that are merged to FE surfaces.
  • *BC_PERIODIC: New command for periodic boundary conditions.
  • *MERGE: Critical bug fix (combination of node splitting and symmetric merge).
  • *OUTPUT_DAMAGE_MAP and *INITIAL_DAMAGE_MAP: Commands to facilitate simulations of multiple fragment impacts and their effect on large targets.
  • *MAT_POWDER_BURN: Bug fixes and general improvements.
  • *MAT_MM_CONCRETE: A new material model for concrete.

Changes in 7.0.154 (2022-09-16)

  • *VELOCITY_CAP: Bug fix in treatment of discrete particles.
  • *CONTACT: Bug fix in contact area calculation (CPU-version).
  • *MAT_MM_CONCRETE: New concrete material model.
  • *PART: Allow for unlimited number of parts (old limit 10,000).
  • *VULNERABLE_AREA_ASSESSMENT: Added 3D hit point coordinates to .imp database (new visualization functionality in GUI).
  • *FREQUENCY_CUTOFF: Added flag to deactivate regular mass scaling of affected parts.

Changes in 7.0.121 (2022-08-12)

  • *MAT_HOT_FORMING: New temperature and rate dependent constitutive model that accounts for recrystallization, precipitation hardening and recovery.
  • Added support for GPU accelerated node acceleration and time integration calculations.
  • *EROSION_CRITERION: New command, that is used to specify element erosion criteria for one or multiple parts (P, PS, ALL).
  • *LOAD_DAMPING: Added support for discrete particles and SPH (DP).
  • *RANDOM_NUMBER_GENERATOR_SEED: New command that can use the system clock to set the seed.
  • *MERGE_FAILURE_BOLT: New merge failure criterion.
  • *PROP_DAMAGE_JC_REGULARIZE: New damage model (Johnson-Cook with regularization).
  • *VULNERABLE_AREA_ASSESSMENT: Extended output to .imp database.
  • *EOS_GRUNEISEN: Fixed time step issue related to elements with bad aspect ratio.

Changes in 7.0.32 (2022-03-30)

  • *LOAD_DAMPING: Added optional parameter for more efficient relaxation.
  • *MERGE: Bug fix in treatment of SPH-FE interfaces.
  • *LOAD_GRAVITY: Added optional scale factor.

Changes in 7.0.30 (2022-03-28)

  • *VULNERABLE_AREA_ASSESSMENT: Accuracy improvement.
  • *PARTICLE_SPH: Added support for fragment list generation.
  • *FREQUENCY_CUTOFF: Critical bug fix.
  • *PARTICLE_SPH_JET_LSC: New command for linear shaped charge (LSC) jet stabilization.
  • *MERGE: Added support for SPH-FE merging.
  • *MAT_JC: Restart initialization bug fix.
  • *CONTACT: Bug fix in handling of pressure dependent friction coefficient.
  • *PARTICLE_DOMAIN: Bug fixes to new GPU based particle-structure contact algorithm (ctype=1).

Changes in 7.0.1 (2022-03-07)

  • *REFINE: Added support for element sets (ES).
  • *MAT_FLUID: Material model can now be used with Finite Elements (not only SPH).
  • *OUTPUT_SECTION: Improved accuracy.
  • *LOAD_UNDEX: Minor accuracy improvement.
  • *MAT_JH_CERAMIC: Fixed bug in SPH implementation.
  • *OUTPUT: Added more fragment output options.
  • Moved contact state information from impetus_stateX.k to impetus_state_contactX.k
  • *PARTICLE_DETONATION: Improved tracking of the detonation front near small objects and sharp corners.
  • *VULNERABLE_AREA_ASSESSMENT: Improved accuracy.
  • *PARTICLE_SPH_JET: Bug fix in jet tip displacement calculation.
  • *CHANGE_PART_ID: New command.
  • *MAT_YEOH: New model for rubber materials.
  • *MAT_BB: Orthodox implementation of the Bergstrom-Boyce model (*MAT_BERGSTROM_BOYCE will eventually be phased out).
  • *PROP_DAMAGE_HC: Added fracture energy parameter GI (J/m^2) for better handling of crack propagation.
  • *INITIAL_DAMAGE_RANDOM: Added option to choose which damage variable to initialize (some damage models distiguish between ductile/brittle or tensile/compressive failure).
  • *PARTICLE_DOMAIN: Added optional particle-structure contact algorithm, accounting for the particle radius.
  • *VULNERABLE_AREA_ASSESSMENT: Added detailed hit spot information (impact angles and armour layer thicknesses).
  • *CONTACT: New option that converts friction work to heat.
  • *MAT_POWDER_BURN: Minor bug fixes.
  • *PARTICLE_SPH: Critical particle filling bug fix.
  • *VULNERABLE_AREA_ASSESSMENT: Improved accuracy and speed.

Changes in 6.0.858 (2021-11-05)

  • *MAT_RIGID: Fixed issue with initial spin calculation for rigid bodies connected to deformable parts.
  • *MERGE_FAILURE_COHESIVE: Improved energy balance during unloading (post failure forces).
  • *LOAD_AIR_BLAST: Tuned implementation for better treatment of reflected waves.
  • *MAT_REBAR: Added option to reduce element size dependency.
  • *VULNERABLE_AREA_ASSESSMENT: Modified gap effect implementation.

Changes in 6.0.846 (2021-10-15)

  • Python: Added a built-in module which allows users to extract curve, table and path data directly from the python script.
  • *VULNERABLE_AREA_ASSESSMENT: Bug fix in handling of user defined impact angle dependency.
  • *MERGE: Added support for node sets.
  • *LOAD_AIR_BLAST: Bug fix in blast wave diffraction calculations.
  • *INITIAL_VELOCITY: Bug fix in handling of local coordinate system.
  • *TRIM_HOLE: Bug fix, multiple commands was not handled properly.

Changes in 6.0.841 (2021-10-04)

  • *ADD_MASS: New directional mass option for bodies submerged in water.
  • *PARTICLE_SPH_JET: Memory bug fix.
  • *CONNECTOR_RIGID: Bug fix.
  • *CONTACT: Added contact penetration contour plot attribute (to .imp database).
  • *MERGE: Improved accuracy when using geometry option (gid).
  • *CONTACT: Friction function bug fix.
  • *FUNCTION: Added vmax_dp, an intrinsic function returning maximum velocity in a particle sub-domain.
  • *COUPLING_REBAR: A new command for user controlled rebar-solid coupling and for rebar element trimming.
  • *MAT_BERGSTROM_BOYCE: Added support for node splitting at failure.
  • *TIME: Added optional initial time variable (to be used when splitting a simulation into multiple stages).
  • *OUTPUT_SECTION: Added temperature to section.out.
  • *PARTICLE_DOMAIN: Improved soil-structure and SPH-structure contact.
  • *MAT_REBAR: Fixed stability issue in rebar-concrete shear slip implementation.
  • *VULNERABLE_AREA_ASSESSMENT: Various small bug fixes.

Changes in 6.0.803 (2021-08-18)

  • GPU: CUDA Context is now properly reset for devices that are not in use.
  • *MERGE: Minor bug fix related to node splitting.
  • *LOAD_THERMAL_RADIATION: New command for thermal radiation.
  • *LOAD_UNDEX: New command for underwater explosion pressure loading.
  • *CONTACT: Contact pressure visualization bug fix.

Changes in 6.0.778 (2021-06-10)

  • *VULNERABLE_AREA_ASSESSMENT: Significant accuracy and performance improvement.
  • *TRIM_SLAB: Bug fix in treatment of linear hexahedra elements.
  • *CONNECTOR_SPOT_WELD_NODE: Memory bug fix and improved output to impetus.info.
  • *PARTICLE_HE: Updated calibrations in built-in explosive library.
  • *PARTICLE_AIR/HE/SOIL: Added particle mass scale factor.
  • *MAT_BERGSTROM_BOYCE: Added tensile failure criterion (limit stretch).
  • *MAT_CABLE: Added yield stress and damage criterion.
  • *COORDINATE_SYSTEM_FUNCTION: Function ID offset bug fix, when reading coordinate system data from an *INCLUDE file.
  • *OUTPUT_SENSOR_THICKNESS: Bug fix in thickness calculation.
  • *PARTICLE_SPH: Updated binary state file format and improved temperature calculation when using *EOS_GRUNEISEN.
  • Node splitting bug fix. At rare occasions, some nodes were not separated at full damage.
  • *PROP_DAMAGE_CL_REGULARIZE: Unit system conversion bug fix.

Changes in 6.0.728 (2021-04-13)

  • *PARAMETER: Improved unit system conversion capabilities.
  • *REFINE: Improved capabilited for pentahedra elements.
  • *PARTICLE_SPH: Bux fix in interaction between different SPH materials. Default setting was incorrectly "no tension", which had a negative impact on shaped charge penetration capacity simulations.
  • *GEOMETRY_PART: Bug fix in SPH and discrete particle filling algorithm.

Changes in 6.0.708 (2021-03-19)

  • *PARTICLE_SPH: Improved treatment of the interaction between different SPH objects.
  • *ELEMENT_REBAR: Added coupling between rebar truss elements and SPH (concrete).
  • *PARTICLE_DETONATION: Added an optional parameter that limits the detonation process to one specific sub-domain ID.
  • *RIGID_BODY_JOINT: Fixed bug related to large joint rotations.
  • *PETRIFY: New command for deformable-to-rigid switching.
  • *GEOMETRY_SEED_COORDINATE: Added part ID option.
  • *REMAP: Improved interpolation scheme.
  • Fixed issue with nested ~if statements.

Changes in 6.0.665 (2021-02-22)

  • *INITIAL_MATERIAL_DIRECTION_PATH: A new command to define initial material directions.
  • *GEOMETRY_COMPOSITE: A new command that combines multiple sub-geometries into one, more complex, geometry.
  • *OUTPUT_CONTACT_FORCE: A new command that act as a contact force sensor. It samples forces and outputs the data in ASCII format (contact_force.out).
  • *VULNERABLE_AREA_ASSESSMENT: Improved geometrical accuracy.
  • *PARTICLE_DOMAIN: Speed-up of particle filling process (faster initialization).
  • *CONTACT_ACCURACY: New command for local control of contact accuracy parameters.
  • *INITIAL_VELOCITY: Added support for velocity definition in local coordinate system.

Changes in 6.0.630 (2021-01-22)

  • Bug fix in resume functionality. Models using python scripts were not handled properly in the past.
  • *PARTICLE_HE: Added particle overlay option for larger time steps during the detonation phase.

Changes in 6.0.624 (2021-01-12)

  • *BC_SYMMETRY: Bug fix related to tetrahedra elements.
  • *PARTICLE_DETONATION: Bug fix related to multiple detonation points.
  • *TRIM_SLAB: Automatic repositioning of sensors after trimming.
  • *PARTICLE_SPH_JET: Added fragment counter and general accuracy improvement.
  • *PARTICLE_SOIL: Added grain overlap check during initialization phase (neighboring sub-domains).

Changes in 6.0.612 (2020-12-17)

  • *BC_TELEPORT: Added a velocity option.
  • *CONNECTOR_SPOT_WELD_NODE: An alternative input format for spot welds.
  • *PROP_SPOT_WELD: A new spot weld property command.
  • *PARTICLE_AIR/HE/SOIL/SPH: Added *FUNCTION based deactivation option.
  • *OUTPUT_ERROR: A new command for user defined error messages in complex command files.
  • *MAT_MOONEY_RIVLIN: Implemented a less conservative critical time step size estimate.
  • *ACTIVATE_ELEMENTS: Extended command to allow for repeating on/off switching.
  • *PARTICLE_SPH: Binary state file bug fix (artificial viscosity was not handled properly).
  • *PROP_DAMAGE_CL_REGULARIZE: Bug fix in component wall thickness calculation.

Changes in 6.0.569 (2020-11-13)

  • This version uses CUDA 11.1 and may require updated graphics driver.
  • *PARTICLE_SPH_JET: A new command for stabilization of shaped charge jets.
  • *BC_TELEPORT: A new command for instantaneous part translations and rotations.
  • *OUTPUT_SENSOR: Moved sensors (in state file output) from impetus_stateX.k to impetus_state_sensorX.k.
  • *PARTICLE_DOMAIN: Minor initialization bug fix (improved accuracy in particle filling).
  • *MAT_LEE_TARVER: Bug fix in JWL EOS implementation.
  • *PARAMETER: Variable name bug fix. Some character combinations were altered by the program.

Changes in 5.0.538 (2020-10-12)

  • *MERGE: Include offset bug fix.
  • Bug fix: User defined seed to random number generator was not working.
  • Unit system conversion bug fix.

Changes in 5.0.536 (2020-10-07)

  • General bug fixes.

Changes in 5.0.512 (2020-09-17)

  • *INITIAL_PLASTIC_STRAIN_FUNCTION: A command that allows the user to initialize parts with effective plastic strain fields.
  • Moved *MERGE data from impetus_stateX.k to a separate file impetus_state_mergeX.k.
  • *PARTICLE_DOMAIN_CLEANUP: A command that is used to deactivate discrete particles.

Changes in 5.0.505 (2020-09-02)

  • *VULNERABLE_AREA_ASSESSMENT: A new simplified tool for ballistic protection evaluation.
  • *PARTICLE_HE: Added explosive type LX-14-0.
  • *ELEMENT_LTET/QTET/CTET: Bug fix in handling of data in impetus_stateX.bin file.

Changes in 5.0.499 (2020-08-24)

  • *PARTICLE_SPH: Added support for initial stresses through the command *INITIAL_STRESS_FUNCTION.
  • *MAT_POWDER_BURN: New material and functionality for propellant combustion. Unburned propellant is modelled as rigid grains and its combustion products as discrete particles.
  • *UNIT_SYSTEM: Added unit system [mm, mg, ms].
  • *PROP_DAMAGE_HC: Added optional strain rate sensitivity.
  • *OUTPUT_SENSOR: Added plastic strain rate to sensor.out.
  • *PARTICLE_DOMAIN: Added initial contact penetration parameter.

Changes in 5.0.477 (2020-08-06)

  • *INITIAL_VELOCITY: Include offset bug fix.
  • *MAT_GRANULAR_CAP: Added optional adhesion damage parameter.
  • Big fix in pinned memory deallocation (GPU).

Changes in 5.0.462 (2020-06-26)

  • *MERGE: Improved penalty based formulation (stiffness definition that accounts for mass scaling).
  • *CONTACT: Bug fix in thermal contact (related to triangular element faces).
  • *INCLUDE_BINARY: Added error message if included binary file is not used.
  • *GEOMETRY_SPHERE: Added optional inner radius (hollow sphere).
  • *MAT_METAL: Added support for temperature dependent heat capacity.
  • *PARTICLE_SPH: Added optional scale factor for particle density (particles per unit volume).

Changes in 5.0.442 (2020-06-04)

  • *COORDINATE_SYSTEM: New Lagrangian cartesian coordinate system type.
  • *PARTICLE_SPH: Improved formulation for reduced tensile instabilty effects.
  • *PARTICLE_SPH: Added temperature output to imp database.
  • *PARAMETER: Information about command file line, where the parameter value is set, has been added to impetus.info.
  • *INCLUDE_BINARY: Improved error handling.
  • Corrected errors in imp database (material damage output).
  • *MAT_BERGSTROM_BOYCE: Unit system conversion bug fix.

Changes in 5.0.394 (2020-05-12)

  • *COORDINATE_SYSTEM_FUNCTION: New flexible command for moving coordinate systems.
  • Fixed issue with heat conduction across *REFINE interfaces.
  • *MAT_CONCRETE and *MAT_CONCRETE_2018: Added associated plastic flow option on pressure cap.
  • *CONNECTOR_DAMPER: A new command for resultant based rubber dampers.
  • *PARTICLE_SPH: Restart bug fix.
  • *SMOOTH_MESH: Improved smoothing for quadratic HEX elements.

Changes in 5.0.358 (2020-04-14)

  • *PARTICLE_AIR: Added support for USER defined air properties.
  • *PARTICLE_HE: Added afterburn physics, where uncombusted detonation products are allowed to react with oxygen in the surrounding air.
  • *COORDINATE_SYSTEM_NODE: Initialization bug fix.
  • *CONTACT: Memory bug fix. A node could not be connected to more than 1000 elements.
  • *PARTICLE_DOMAIN: GPU memory is now released if particle deactivation time is reached before the simulation ends.

Changes in 5.0.329 (2020-03-19)

  • *SUBDIVIDE_PART_THICKNESS: Bug fix. Multiple commands were not handled correctly.
  • *OUTPUT_USER: Bug fix. Incorrect handling of *INCLUDE offset.

Changes in 5.0.321 (2020-03-12)

  • Fragment output bug fix.

Changes in 5.0.320 (2020-03-12)

  • *MAT_GRANULAR_CAP: Added support for density dependent elastic properties.
  • *CONTACT: Added option for better treatment of sharp edges.
  • *FUNCTION: Added optional tolerance to control volume calculation vol_geo(ID, tol) and vol_geo0(ID, tol). The functions return a zero if the relative error is larger than tol.
  • *PARAMETER: New functionality to allow for local parameters.
  • *MAT_MMC: Added default strength cap.
  • *ELEMENT_REBAR: Added support for mass scaling.
  • *ELEMENT_REBAR: Mesh can now be refined with the command *REFINE.
  • *ELEMENT_REBAR: Stresses, strains and damage is now written to impetus_state_rebarX.k.
  • *OUTPUT: Extended fragment output (removed node splitting requirement).
  • *LOAD_AIR_BLAST: Tuned implementation for higher accuracy of hemispherical charges on ground.
  • *PARTICLE_SPH: Resume including material state (stresses, history variables).

Changes in 5.0.278 (2020-02-12)

  • *LOAD_AIR_BLAST: Unit system bug fix.
  • *SUBDIVIDE_PART_THICKESS: Memory bug fix.
  • *LOAD_THERMAL_SURFACE: Fixed issue related to symmetry planes.
  • *MAT_MMC: General updates.
  • *PARTICLE_DOMAIN: Improved particle-structure contact algorithm.

Changes in 5.0.264 (2020-01-21)

  • *BC_MOTION: Improved implementation to prevent unwanted nodes from being constrained to the symmetry plane.
  • *OUTPUT_SECTION: Bug fix related to materials using node splitting.
  • *MERGE: Improved handling of cohesive failure when using penalty based formulation.
  • Node splitting bug fix (type 4 crack direction calculation).

Changes in 5.0.240 (2020-01-08)

  • *MAT_CERAMIC: Bug fix in handling of initial damage distribution.
  • *UNIT_SYSTEM: Bug fix in unit system converter (~convert_from).
  • *FUNCTION: Added built-in function for maximum plastic strain in part (epsp_part).
  • *PARTICLE_DETONATION: Added support for functions in detonation point definition.
  • *BC_TEMPERATURE: Added support for prescribed temperature in geometry (entype=G).
  • *INITIAL_TEMPERATURE: Added support for initial temperatures at nodes (entype=N).

Changes in 5.0.222 (2019-12-09)

  • *EOS_JWL: Fixed card reading error.

Changes in 5.0.221 (2019-12-03)

  • *PARAMETER/*FUNCTION: Added modular function (mod(a,b)).
  • *CONNECTOR_GLUE_LINE/*CONNECTOR_GLUE_SURFACE: Bug fix in energy book keeping.
  • *MAT_HSS: Bug fix to Hosford yield criterion.
  • *MAT_CREEP: Improved numerical accuracy in handling of creep flow.
  • *OUTPUT_SENSOR: Added creep strain for *MAT_CREEP.
  • *CONTACT: Bug fix in eroding contact.
  • *LOAD_FORCE: Improved force distribution for higher order elements.
  • *VELOCITY_CAP: Added option for velocity cap on HE/AIR particles.
  • *PARTICLE_DOMAIN: Improved restart functionality.
  • Gamma-SPH: General improvements.
  • Fixed GPU compatibility problem.

Changes in 5.0.205 (2019-11-14)

  • Fixed crash bug in Performance benchmark under Linux.

Changes in 5.0.203 (2019-11-13)

  • *COMPONENT_CYLINDER: Added symmetry options and improved mesh.
  • *TRIM_HOLE: New mesh command for hole cutting.
  • General bug fixes.

Changes in 5.0.185 (2019-10-09)

  • Updated SPH-module with new and improved functionality.

Changes in 5.0.179 (2019-10-03)

  • *MAT_HSS: Added strain rate hardening option.
  • *MAT_LEE_TARVER: Added reference pressure for convenient conversion between unit systems.
  • *MAT_MOONEY_RIVLIN: Added support for thermal properties.
  • *PARTICLE_DOMAIN: New ASCII file particle_sub_domain.out.
  • *SUBDIVIDE_PART_THICKNESS: A new mesh command for subdividing structures into multiple layers.
  • General bug fixes.

Changes in 5.0.169 (2019-09-23)

  • General bug fixes.

Changes in 5.0.167 (2019-09-17)

  • General bug fixes.
  • *MERGE: Added optional parallelism tolerance.
  • *MAT_FABRIC: Added C-L damage to matrix material and improved transition between compression and tension for woven fabrics.
  • *OUTPUT: Added option for dump and state file output.
  • General bug fixes.

Changes in 5.0.102 (2019-06-28)

  • *MERGE: Output maximum stress levels to merge.out.
  • *RIGID_BODY_UPDATE: New command to control time integraton of rigid bodies.
  • General bug fixes.

Changes in 5.0.94 (2019-06-03)

  • *MAT_METAL: Added Hosford yield criterion.
  • *CONTACT: Improved treatment of sharp edges and added heat flux to contact.out.
  • *INITIAL_STATE_HAZ: Automatic assignment of sigy0 to weld seam part.
  • *FUNCTION: Added access to sensor data depsps, sig1s and dmgs.
  • *LOAD_THERMAL_SURFACE: Created ASCII file load_thermal_surface.out (energy and heat flux data).
  • *CONTACT: Added contact area to contact.out.
  • *OUTPUT_SENSOR_THICKNESS: New sensor for thickness measurement.
  • *PARTICLE_DOMAIN: Added soil/SPH forces to particle_contact.out.
  • Added support for variables in command titles.
  • General bug fixes.

Changes in 5.0.55 (2019-05-07)

  • *MERGE: Improved handling of distorted meshes.
  • General bug fixes.

Changes in 5.0.52 (2019-04-29)

  • General bug fixes.
  • *CONNECTOR_GLUE_LINE: Output more information to impetus.info.

Changes in 5.0.45 (2019-04-09)

  • Critical bug fix in function parser.

Changes in 5.0.44 (2019-04-08)

  • *FUNCTION: Fixed bug where normal expressions were interpreted as python calls.
  • Fixed bug when Engine didn't crash properly after getting CUDA error.
  • *MAT_BERGSTROM_BOYCE: Optional updates that make the implementation equivalent to Bergströms original model.
  • General bug fixes.

Changes in 5.0.28 (2019-03-28)

  • *FUNCTION: Added support for custom Python functions.
  • Updated to CUDA version 10.1 which requires display driver 418.96 or newer.
  • *CONTACT: Added accuracy option.
  • *OUTPUT_USER_COLLECTION: New command for ASCII time history output for collections of nodes or elements.
  • *MAT_VISCO_PLASTIC: Added parameter to control stiffness of non-linear elastic network.
  • *PROP_DAMAGE_CL_REGULARIZE: New damage model with regularization feature for coarse element grids.
  • *OUTPUT_J_INTEGRAL: New command for fracture mechanics.
  • *BC_MOTION: Added feature for complex activation/deactivation criteria.
  • *FUNCTION: Added built-in Kronecker delta function.

Changes in 4.0.2614 (2019-02-19)

  • General bug fixes.

Changes in 4.0.2611 (2019-02-13)

  • *FUNCTION: Added intrinsic functions for joint spin (sxj, syj, szj).
  • *SECTION_OUTPUT: New command for cross section output (force, bending moment and area).

Changes in 4.0.2601 (2019-01-29)

  • General bug fixes.

Changes in 4.0.2594 (2019-01-23)

  • General bug fixes.
  • *RIGID_BODY_JOINT: Allow for analytical torque functions.
  • New node splitting type (erode=4).
  • *MAT_METAL and *MAT_HSS: Added support for temperature dependent heat expansion coefficient.

Changes in 4.0.2569 (2018-12-10)

  • Bug fix in node splitting algorithm.

Changes in 4.0.2567 (2018-11-29)

  • Minor bug fixes.

Changes in 4.0.2566 (2018-11-23)

  • General bug fixes.

Changes in 4.0.2560 (2018-11-01)

  • Fixed GPU error in performance benchmark.

Changes in 4.0.2557 (2018-10-25)

  • General bug fixes.
  • *COMPONENT_BOX_IRREGULAR: New mesh command.
  • *PROP_DAMAGE_CL and *PROP_DAMAGE_BRITTLE: Added optional pressure dependency.
  • *MAT_LEE_TARVER: Material model for "deflagraton to detonation" simulations.
  • *MAT_TRIP: Material model that accounts for transformation induced plasticity (austenite and martensite).
  • *OUTPUT_SENSOR: Added pressure over yield stress and first principal stress to sensor.out.
  • *MAT_HSS: Material model for high strength steels in ballistic applications.
  • *PROP_DAMAGE_HC: Hosford-Coulomb damage model.
  • *UNIT_SYSTEM: Added MMGMS [mm,g,ms].
  • License check is now integrated with impserver.
  • *PBLAST: This command is no longer supported. Users should use *PARTICLE_DOMAIN instead.

Changes in 4.0.2492 (2018-07-06)

  • *SMOOTH_MESH: Added support for smoothing inside geometry.
  • *PROP_DAMAGE_BRITTLE: Added parameter to control pressure dependence in tensile fracture.
  • *PARTICLE_SPH: Added support for *MAT_METAL, *MAT_HJC_CONCRETE, *MAT_JH_CERAMIC and *MAT_FLUID.
  • *MAT_CONCRETE: Improved treatment of viscous effects for larger critical time step size.
  • *UNIT_SYSTEM: Added [g, cm, s, K].
  • *MAT_CERAMIC: Added tensile cut-off for crushed material.
  • *RIGID_BODY_JOINT: Added critical time step calculation.

Changes in 4.0.2452 (2018-04-25)

  • GPU updates for Volta architecture.
  • *MAT_FABRIC: Improved shear stiffness formulation.
  • *LOAD_AIR_BLAST: Improved description of negative pressure phase.
  • General bug fixes.

Changes in 4.0.2425 (2018-04-08)

  • *CONTACT: General improvements and bug fix in contact wear calculation.
  • *PARTICLE_DOMAIN: Improved flow velocity and pressure output from discrete particles.
  • *PROP_THERMAL: Added support for temperature dependent heat capacity.

Changes in 4.0.2425 (2018-03-19)

  • *MAT_VISCOUS_FOAM: Added hysteresis parameter.
  • General bug fixes.
  • Faster license check.
  • Multi-GPU bug fixes.

Changes in 4.0.2394 (2018-02-28)

  • *CONTACT: Improved the algorithm with better face and edge treatment.
  • *PARAMETER: Added support for vectors.
  • *TABLE: Added access to *TABLE data in parameter expressions.
  • General bug fixes

Changes in 4.0.2318 (2017-12-17)

  • *MAT_FABRIC: Added material viscosity parameter.

Changes in 4.0.2318 (2017-12-06)

  • *INITIAL_VELOCITY: Added discrete particle (DP) as viable entity type.
  • *PARTICLE_SPH: Improved SPH formulation for materials with strength.
  • *PARTICLE_DOMAIN: Bug fix (reflective boundary condition was not correct).
  • *PARTICLE_DOMAIN: Improved handling of delayed detonation (programmed burn path is now computed at detonation time).
  • *PARTICLE_DOMAIN: Improved spatial impulse smoothing formulation (parameter xsmooth).
  • *GEOMETRY_EFP: Added one more parameter in the geometry definition.
  • *MAT_VISCOUS_FOAM: New foam material model.
  • *PRESTRESS_BLIND_HOLE_BOLT: Added automatically generated *MERGE command to impetus_state_boltX.k.
  • Added material direction output to imp-database.

Changes in 4.0.2302 (2017-11-07)

  • *MAT_CREEP: Critical bug fix in GPU-implementation.
  • *PARTICLE_DOMAIN: Speed up of initialization process.
  • *MAT_FABRIC: Modified evolution of damage softening.
  • Added momentum of eroded mass to ASCII file part.out.
  • *MERGE: Bug fix in combination self-merge and node splitting.

Changes in 4.0.2302 (2017-10-18)

  • More accurate report of used GPU memory

Changes in 4.0.2291 (2017-10-03)

  • Added support for element sets (ES) in *ACTIVATE_ELEMENTS and for geometries (G) in *MERGE.
  • *FUNCTION: Added intrinsic function for maximum damage in element set (dmg_es).

Changes in 4.0.2277 (2017-08-25)

  • *CONNECTOR_GLUE_LINE: Improved interpolation between normal and shear loading.
  • *CONNECTOR_SPOT_WELD: Bug fix - ductility was not correct in mixed mode loading.
  • *CONTACT: More calculations done on GPU with new broad search algorithm.
  • *CURVE: Using (optional) title as abscissa name in curve_X.out.
  • *ELEMENT_REBAR/COMPONENT_REBAR: Bug fix in rebar diameter (could not read the data from the *PART command).
  • *LOAD_AIR_BLAST: Tuned diffraction algorithm.
  • *MAT_CERAMIC: Modified implementation for more flexibility in describing tensile fracture.
  • *MAT_FABRIC: Added GPU support.
  • *MERGE: Improved automatic conversion to penatly formulation whenever constraint based method fails.
  • *PART: Added user defined particle radius in element-to-particle conversion.
  • *PARTICLE_DOMAIN: Fixed issue in particle-structure contact (face normal problem - extremely distorted elements).
  • *PARTICLE_DOMAIN: Modified element to particle conversion (look for overlap between particles and elements to prevent leakage).
  • *PRESTRESS_BOLT: Improved algorithm to identify bolts/nuts.
  • *REFINE: Improved algorithm for detection of through thickness direction.
  • *RIGID_BODY_JOINT: Added user defined stiffness.
  • Initialization: Better and faster memory handling.
  • Multi-GPU: Better memory handling. If Element processing cannot be split into equal parts (per GPU), fill mode will be used instead.

Changes in 4.0.2225 (2017-06-03)

  • *MAT_FABRIC: new material model for fabrics.
  • *PARTICLE_DOMAIN: Added thermal velocity for complex burn laws.
  • Added state file for *PARTICLE_DOMAIN.

Changes in 4.0.2207 (2017-05-19)

  • *LOAD_AIR_BLAST: a new command for air blast loading of structures.

Changes in 4.0.2157 (2017-04-26)

  • Fixed bug in GPU scheduler.
  • Improved error message handling.
  • Fixed bug in unit conversion.
  • Fixed bug in GPU memory transfer.
  • This is the last release using CUDA 6. Future updates will be utilizing CUDA 8.

Changes in 4.0.2107 (2017-03-13)

  • Fixed critical bug in multi-GPU implementation of node-splitting.
  • Added support for faster memory communication between multiple GPUs if hardware allows it.
  • *TABLE: a new command for tabulated data.
  • *PATH: a new command for definition of path in space.
  • *CONNECTOR_SPOT_WELD: a new command for spot welds.
  • *CONNECTOR_GLUE_LINE: a new command for definition of adhesive bonds between surfaces.

Changes in 4.0.2090 (2017-02-17)

  • Fixed critical contact bugs.
  • *VELOCITY_CAP: a new command that defines an upper limit to node and discrete particle velocities.

Changes in 4.0.2081 (2017-02-03)

  • General bug fixes.

Changes in 4.0.2070 (2017-01-27)

  • *FUNCTION: added intrinsic functions for access to joint and sensor data.
  • *OUTPUT_USER: a new command for user defined ASCII output.
  • *OUTPUT_SENSOR: sensors are now written to impetus_stateX.k.
  • *INCLUDE: added material ID offset and a general command ID offset.
  • *RIGID_BODY_JOINT: added user defined damping.

Changes in 4.0.2055 (2017-01-12)

  • Fixed bug in automatic GPU selection for devices in WDDM mode.
  • Fixed bug in GPU selection where the solver didn't choose the specified device.
  • Added GPU boost functionality for Tesla GPUs (K40, K80, P100, etc)

Changes in 4.0.2022 (2016-12-09)

  • *PRESTRESS_BLIND_HOLE_BOLT: a command for prestressing blind hole bolts.

Changes in 4.0.2020 (2016-12-02)

  • More efficient GPU memory handling.
  • Added GPU support for Mie-Gruneisen equation-of-state.
  • *PARTICLE_DOMAIN: GPU speedup.
  • Added resultants to "prescribed.out" for more convenient plotting.

Changes in 4.0.2004 (2016-11-17)

  • *CONTACT: improved treatment of facets in contact that are nearly orthogonal.

Changes in 3.0.1994 (2016-11-09)

  • General optimizations and bug fixes.

Changes in 3.0.1977 (2016-10-20)

  • *MAT_JC: extended thermal softening law.
  • Performance benchmark feature added.

Changes in 3.0.1966 (2016-10-04)

  • *PARTICLE_DOMAIN: opened up for user defined HE and SOIL.
  • *OUTPUT_SENSOR: option for displacement output relative local/global coordinate system.
  • *MAT_HOEK_BROWN: new material model for rock masses.

Changes in 3.0.1956 (2016-09-23)

  • Additional parts of acceleration is now GPU supported.
  • *MAT_FORMING_R: added damage softening option.
  • Fixed bug in Materials library where the solver couldn't find the DLL file.
  • *PARTICLE_DOMAIN: GPU implementation added.
  • Various fixes in both impetus.info and ASCII output files.

Changes in 3.0.1919 (2016-09-01)

  • *CONTACT: optimized and improved search algorithm.
  • *RIGID_BODY_JOINT: improved output to impetus_stateX.k file.
  • General optimizations and bug fixes.
  • *MAT_BERGSTROM_BOYCE: added alternative viscous damping law.
  • *PARTICLE_DOMAIN: more flexible input structure for discrete particles/SPH (currently no GPU support).

Changes in 3.0.1882 (2016-08-05)

  • *PBLAST: extended library of built in high explosives + added functionality to model water.

Changes in 3.0.1867 (2016-06-14)

  • *RIGID_BODY_JOINT: extended functionality.
  • *MAT_BERGDTROM_BOYCE: new material model for polymers and rubbers.
  • *MAT_REBAR: added flag to activate/inactivate bending stiffness.
  • Improved input error handling.
  • Various bug fixes.