Version 971 R4.2 offers the following new features and enhancements not offered
in the previous release R3.2.1. The items in this list are presented in no
particular order and the list is not completely comprehensive. Certainly, not
every minor bug fix and small improvement is mentioned.
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Added the ability to generate superelement representations of parts
using Static Condensation, see *CONTROL_IMPLICIT_STATIC_CONDENSATION.
Extended *CONTROL_IMPLICIT_MODES to include eigenmodes and optionally
generate the superelement representation of the part. This enables
the LS-DYNA to build the Craig-Bampton linear representation of a part
using constraint and eigenmodes.
Superelements constructed by *CONTROL_IMPLICIT_STATIC_CONDENSATION
and *CONTROL_IMPLICIT_MODES are written in either the Nastran extended
format for DMIG files or a LS-DYNA binary format, which reduces the size
of the file. *ELEMENT_DIRECT_MATRIX_INPUT has been extended to read
the binary format.
*CONTROL_IMPLICIT_TERMINATION has been extended to allow user control
over termination the simulation in ways other that the end time. Energy
based tests have been added to the original displacement control.
Enhanced the robustness and speed of the nonlinear solution process
for implicit mechanical transient simulation. An area of special focus
has been metal forming applications. We have added a contact penetration
checking option (see *CONTROL_IMPLICIT_SOLUTION) and a new keyword
*CONTROL_IMPLICIT_FORMING.
A collocation boundary element method is developed based on
Burton-Miller formulation, to solve the irregular frequency problem for
exterior acoustics. This method is available now for SMP and MPP.
Two preconditioners are adopted for boundary element acoustic
solvers, thus the solution process is now faster.
Extended Rayleigh acoustic method to MPP.
Added empirical pressure loading module for treating multiple blast sources.
Also now possible to define the location of the blast using a node ID.
Also, a death time for blast can be specified.
(*LOAD_BLAST_ENHANCED)
Added airburst blast loading which takes takes into account ground
reflected waves and formation of a Mach stem wave.
(*LOAD_BLAST_ENHANCED)
Added blast loading from missile delivered warhead (shaped charge or exlosively
forged projectile) which produces a non-spherical blast front.
(*LOAD_BLAST_ENHANCED)
Added binary database for visualizing blast pressures applied to structures.
(*DATABASE_BINARY_BLSTFOR)
Added orientation of a rigid body by specifying the time history of components
of a body fixed vector. The remaining free rotational degree of freedom
(rotation about the vector axis) can be also be specfied as either zero,
constant or a function of time.
(*BOUNDARY_PRESCRIBED_ORIENTATION_RIGID)
Added optional death time for *BOUNDARY_PRESCRIBED_ORIENTATION_RIGID.
Added new options for *DEFINE_CURVE_FUNCTION:
- ELHIST: monitors elemental quantities such as stress and strain
- RCFORC: monitors contact interface forces
- Possible to prescribe the acceleration of a rigid body as function of
model reresponse.
Added an optional _ID to *INTERFACE_COMPONENT_*.
Added command *INTERFACE_COMPONENT_FILE to specify name and format (LSDA is
now the default format) of interface database that is written.
"z=" on execution line will override this command.
Similarly, added command *INTERFACE_LINKING_FILE to specify name of interface
database that is read. "l=" on execution line will override the command.
Added capability for a "skew angle" option in sliprings for better
friction modeling. It requires the input of an orientation node, and a
second friction coefficient (or a user defined friction function), and
computes friction based on the wrap angle (as seen when looking "down the
slipring axis", ie the cylinder the belt passes over) and the skew angle
(how much the belt twists as it passes over the slipring).
Simple one-step, implicit solution for gravity loading of models which may even
include contacts and unattached parts is now possible.
Available in SMP and MPP.
(*CONTROL_IMPLICIT_FORMING (may be renamed later))
Added thick shell formulation 5 (ELFORM=5 on *SECTION_TSHELL). It has
1 integration point per layer and calls 3D stress update routines. It
uses an assumed strain field for accurate bending stiffness and improved
behavior with layered anisotropic materials.
Added segment based (SOFT=2) contact options:
- DEPTH=13. Behavior is similar to DEPTH=3, but it has been tuned to
improve energy conservation
- DEPTH=23. Behavior is similar to DEPTH=3, but contact detection uses a
new algorithm intended to improve robustness.
- Automatically split quad shell segments into 2 triangular segments.
- Report penetrations of shell mid-planes.
- Use a moving average of the current time step in the penalty stiffness
calculation rather than the initial time step.
Added RTCL damage to *MAT_123/*MAT_MODIFIED_PIECEWISE_LINEAR_PLASTICITY.
Added *MAT_220/*MAT_ORTHOTROPIC_ADVANCED_DAMAGE, for solid elements.
Added beam spot weld failure option -9 which is like 9 except that
beams do not fail.
Added autojump controls for superplastic forming.
Improvements to EFG (Element Free Galerkin):
- Added adaptiviity for solid EFG and shell EFG in MPP.
- Implemented an explicit version of stablized EFG method for 8-noded and
6-noded integration cells.
- Implemented a formulation switch from stablized method to conventional
EFG method controlled by time and other parameters.
- Implemeneted an EFG fracture formulation for 4-noded integration cell.
- Added MPP for adaptive EFG method for solid formulation and shell
formulation.
- Included MPP thermal solver in the adaptive EFG formulation for solids.
Added coupling of ALE ambient type 5 elements with *LOAD_BLAST_ENHANCED
wherein pressure and velocity BC applied to ambient ALE elements are provided
by *LOAD_BLAST_ENHANCED.
Added *ALE_AMBIENT_HYDROSTATIC and *INITIAL_HYDROSTATIC_ALE
for initializing and prescribing hydrostatic pressure in ALE liquids
due to gravity.
Added MPP support for self piercing rivet.
(*CONSTRAINED_SPR, *CONSTRAINED_SPR2)
Improvements to *AIRBAG_PARTICLE:
- Support of heat convection in CPM to account for heat loss to ambient.
- Performance improvement for CPM method.
- Added option for dynamic particle radius scaling.
- Added ELA support for MAT_FABRIC.
- Added particle-to-structure momentum transfer option
Implemented new ALE 2D capabilities and mapping to ALE 3D
(*CONTROL_ALE2D)
*MAT_171 (*MAT_STEEL_CONCENTRIC_BRACE) – hysteretic algorithm improved to avoid
the possibility of a step change of result for small changes of input. New
input field EPTCRIT. Also, fixed bug in loadcurve option.
*MAT_169 (*MAT_ARUP_ADHESIVE) – added new optional input parameter BTHK (bond
thickness – by default, this is taken from the element dimension). Also, fixed
bug that would have prevented wedge elements from working correctly.
Also added input parameter THKDIR to allow thickness direction to be taken
from element topology rather than smallest element dimension.
*MAT_172 (*MAT_CONCRETE_EC2) – less conservative timestep calculation; enable
stiffness-method hourglass control; new option for concrete compressive
behaviour following Mander’s algorithm (TYPEC=6); new input parameter UNLFAC
controlling unload stiffness; shear capacity calculations; reinforcement
directions may be specified using AOPT inputs.
End-releases for *MAT_191 (*MAT_SEISMIC_BEAM) now tolerant of being connected
to constrained nodes.
New *MAT_202 (*MAT_STEEL_EC3) for use in fire analysis – integrated beam
elements only.
New keyword *LOAD_THERMAL_VARIABLE_BEAM – similar to
*LOAD_THERMAL_VARIABLE_SHELL – allows temperatures in beam elements to vary
piecewise-linearly over the cross-section.
Fix for beams with end-releases written to dynain file – the topology written
to dynain is now the beam’s original topology.
Staged construction – dormant elements now written to d3plot file as “deleted”,
so user can see only the active elements at any time; data for penalty-method
tied contacts is now written to the dynain file allowing smooth restarting
from that dynain file.
Added damping energy calculation for *DAMPING_FREQUENCY_RANGE
Pore pressure analysis for geotechnical models, allowing modeling of drained or
undrained pore water, time-dependent consolidation, or calculation of
steady-state pore pressures. New keywords:
*BOUNDARY_PORE_FLUID
*BOUNDARY_PWP_option
*CONTROL_PORE_FLUID
*DATABASE_PWP_OUTPUT
*DATABASE_PWP_FLOW
*MAT_ADD_PERMEABILITY
*INITIAL_PWP_DEPTH
Steady state rolling analysis is a generalization of *LOAD_BODY, allowing
the user to apply body loads to part sets due to translational and rotational
accelerations in a manner that is more general than the *LOAD_BODY capability.
This capability is useful for initializing the stresses and velocity of tires
during dynamic relaxation, and rolling processes in manufacturing. Still
undergoing development. New keywords:
*LOAD_STEADY_STATE_ROLLING
*CONTROL_STEADY_STATE_ROLLING
Added a new database, *DATABASE_ATDOUT for the automatic tiebreak
damage option.
Modifications for *MAT_017 (*MAT_ORIENTED_CRACK). Crack propagation to adjacent
elements via two new input parameters: SOFT and CVELO.
New argument for user friction interface USRFRC: plastic strain at
slave node as average value from surrounding solid or shell elements.
Improvements to *MAT_187 (*MAT_SAMP-1):
- Handling of strain rates and damage.
- Bug fix when used with penta elements.
- New parameter RBCFAC (Card 1, Column 7) is the ratio of yield in biaxial
compression vs. yield in uniaxial compression.
Added new option to cohesive *MAT_138 (*MAT_COHESIVE_MIXED_MODE): parameters T
and/or S can now be negative. The absolute value then defines a load curve for
now be negative. The absolute value then defines a load curve for
peak traction(s) vs. element size. This should be helpful in case
of coarse meshes.
Read reference geometry flag (REF) for *MAT_183
(*MAT_SIMPLIFIED_RUBBER_WITH_DAMAGE): Card 3, Column 2.
Extension of *MAT_120_JC (*MAT_GURSON_JC): new material parameters KW, BETA,
and M are read on new optional Card 7, Columns 1, 2 and 3. KW and BETA are
used in Hutchinson model (void growth under shear) and M is for
enhanced JC failure (nonlinear damage evolution).
Added information about element ID in cohesive usermat routine.
Added new option to automatic tiebreak contact opt 9/11 (Dycoss):
Parameters NFLS and/or SLFS can now be negative. The absolute value
then defines a load curve for peak traction(s) vs. segment size.
This should be helpful in case of coarse meshes.
Added optional thickness scaling for *INCLUDE_STAMPED_PART (new real
parameter on Card 3, Column 8).
Bug fix for dynain writing of thick shell initial stresses.
Fix for reading of *INITIAL_STRESS_SOLID with EOS history variables.
New options for *MAT_054 (*MAT_COMPOSITE_DAMAGE_ENHANCED) for shells:
- New parameter PFL (Card 7,Column 1) defines the percentage of layers which
must fail until crashfront is initiated (reduced strengths in neighbor
elements).
- Linear damage for transverse shear defined by 3 new input parameters:
damage initiation strain, final rupture strain, and transverse shear
maximum damage.
Added d3hsp output of DTSTIF from Contact Optional Card C for SOFT=1.
Enable hourglass control type 6 for solid element material *MAT_123
(*MAT_MODIFIED_LINEAR_PIECEWISE_PLASTICITY).
Fix for symmetric mapping (*INCLUDE_STAMPED_PART_... with ISYM>0).
When mirroring the stress/strain tensor, 2 of the 3 shear stresses change
sign. It was changed for all 3 shear stresses before, which was wrong.
New large format for *INITIAL_STRESS_SHELL.
Changes to *MAT_077 (*MAT_HYPERELASTIC_RUBBER, *MAT_OGDEN_RUBBER):
- Enable to work with tet formulation 13.
- Added reference geometry option (Card 1, Column 8).
Fix for *MAT_089(*MAT_PLASTICITY_POLYMER), solids were not eroded after failure.
Added option to enable a 'mapping only' run by setting INCOUT=4
in *INCLUDE_STAMPED_PART.
Improvements to *MAT_036 and *MAT_133 (*MAT_3-PARAMETER_BARLAT and
*MAT_BARLAT_YLD2000):
- Added Chaboche-Roussilier kinematic hardening.
- Added consistent viscoplasticity from tables.
Consistent thermal contact algorithm for mechanical contact SOFT=2 and in
particular for contact with 6-noded segments from 10-noded tetrahedra.
Material parameters defined by load curves in *MAT_006 (*MAT_VISCOELASTIC).
New fully integrated solid elements to reduce transverse shear stiffness for
elements with poor aspect ratio (element types -1 and -2).
Nonzero through thickness stress for shell elements 2 and 16 when used in
contact.
Improvements to *MAT_103 (*MAT_ANISOTROPIC_VISCOPLASTIC):
- Multiphase description, i.e., the material can consist of several phases
where each has its own set of constitutive parameters.
- Added consistent viscoplasticity (directly) from tables.
- User damage available (not only failure).
Thermal composite shells available in *PART_COMPOSITE.
Possibility to mix thick and thin thermal shells within one model.
Segment to segment mortar contact for implicit contact analyses.
Added *MAT_*MAT_UHS_STEEL, an advanced material for hot stamping simulations
including 5 phases, 4 phase transitions and trip effects. This model is
available for both for solids and shells.
Added thermal effects for 2D and 3D SPH elements (*MAT_THERMAL_ISOTROPIC).
Added a Lagrangian kernel for 3D SPH elements (IFORM=7 and IFORM=8 for the
renormalized lagrangian kernel).
Added new keyword *COMMENT.
Added optional _TITLE for *PARAMETER and *PARAMETER_EXPRESSION.
Added IOOPT option for *DATABASE_BINARY_INTFOR (Card 3).
Added new keyword *DATABASE_EXTENT_D3PART to control the output of d3part.
Added a new option c=-cputim.
The absolute value of cputim will be used to terminate the restart job
based on the cpu time of the current run and not the cumulative cpu time.
This negative cputim can be input as a command line option or in the
first field of *CONTROL_CPU.
*DATABASE_EXTENT_BINARY
4th optional card, 1st field
dtdt=0, no action
dtdt=1, dump nodal temperature rate dT/dt to d3plot
*CONTROL_THERMAL_SOLVER
2nd optional card, 8th field
TSF = thermal speedup factor (default 1.)
This parameter will scale all thermal velocity terms (e.g., heat
transfer coefficient) for use with mechanical time scaling (e.g.,
artificially increasing the punch velocity).
*CONTROL_CONTACT
6th card, 3rd field
ithcnt < 0: conduction evenly distributed (pre-R4)
= 0: default set to 1
= 1: conduction weighted by shape functions, reduced integration
= 2: conduction weighted by shape functions, full integration
*CONTROL_THERMAL_SOLVER
SOLVER = -1: symmetric direct solver (ACTCOL)
SOLVER = 1: reset to use solver 11
Added viscoplastic model to *MAT_124 (*MAT_PLASTICITY_COMPRESSION_TENSION).
Add Birth and Death time to *BOUNDARY_SPC option.
Added option to *MAT_83 (*MAT_FU_CHANG_FOAM) to reload on original loading
curve when damage is active.
Changed damping in *MAT_181 (*MAT_SIMPLIFIED_RUBBER/FOAM) foam option to
correct nonphysical transverse deformation under compression.
Add t=0 state to d3drlf database.
Added friction and energy calculations to *CONTACT_GUIDED_CABLE.
Friction is an option in the manual, but was not implemented in the coding.
Fix for *MAT_133 (*MAT_BARLAT_YLD2000) load curve option.
Fix for missing internal energy for linear solid element.
Added warning message if Part and nodal rigid body share the same ID's.
Added part option to dynamic relaxation, IDRFLG=3.
Added rigid surface contact output to rcforc file.
Fixed *MAT_ADD_EROSION to work properly with multiple failure criteria.
Hardwire contact deathtime to 1.e+20 during dynamic relaxation.
Fix for problem with MCID option on *ELEMENT_SHELL definition.
Fix for *PART_MOVE so it works correctly with 10 node tetrahedron
elements.
Fix spall options 1,2, and 3 in *MAT_015 (*MAT_JOHNSON_COOK) for shell elements.
Bug fix for thick shells when used with contact entities.
Added SET option to *DAMPING_PART_STIFFNESS and *DAMPING_PART_MASS.
Added consistent mass matrix to 10-node tetrahedral element type 16.
Added option to *LOAD_MOVING_PRESSURE to scale the pressure based on the
distance between the nozzle and the surface.
Write dynain file when terminating on cycle number rather than time.
Fix for rigidwall energy calculation when two rigid bodies impact.
Fix incorrect mass reported for seatbelt parts.
Added rate effects to *MAT_003 (*MAT_PLASTIC_KINEMATIC) for beam elements for
the option VP=0.
Fix for *EOS_GASKET related to unloading option.
Fix for secforc calculation when tet type 4 is used in the meshing.
Fix for energy conservation problem with shell type 16 when warping
stiffness is active.
Fix for *MAT_105 (*MAT_DAMAGE_2) to fail element on plastic strain as documented
in the users manual.
Echo *MAT_ADD_THERMAL_EXPANSION data into the d3hsp file.
Write node set of untied nodes for easy viewing in LS-PrePost.
Fix for *PART_MOVE when used with a part defined by PART_COMPOSITE.
Reference surface offsets now work for *PART_COMPOSITE.
Perfectly matched layer material for absorbing outgoing waves from a
computational domain, thus simulating wave propagation in unbounded
domains. Available as
*MAT_230/*MAT_PML_ELASTIC (Elastic material)
*MAT_230_FLUID/*MAT_PML_FLUID (Elastic fluid material)
*MAT_237/*MAT_PML_HYSTERETIC (for Biot hysteretic material)
*MAT_231/*MAT_PML_ACOUSTIC (Acoustic media)
Biot hysteretic material for modelling frequency-independent damping.
(*MAT_232/*MAT_BIOT_HYSTERETIC)
Nonlinear soil-structure interaction invoked via
*INTERFACE_SSI
*BOUNDARY_FREE_FIELD_GROUND_MOTION