Crash and Safety

•	Finite Volume Mesh (FVM) Airbag improvements:

-	Solution efficiency: The FVM computation is disabled until the airbag firing time, TTF.

-	Injector Definition: The inflator can now be defined on an isolated internal surface giving increased flexibility when modeling airbags.

-	Mass flow time history output for internal surfaces: The mass flow between internal airbag chambers can now be output to the time history file.

-	FVM tetra mesh coordinate output: When debugging issues with the FVM tetra mesh, the coordinates of the FVM tetra mesh can now be output.

-	FVM algorithm improvements, /LEAK: The FVM algorithm was improved to account for gas pressure applied to porous airbag fabric which is defined in the /LEAK.

•	Vent hole naming: Vent holes can now be identified with a specific name in /MONVOL definition and are output by default in the time history file.

•	/EREF, /REFSTA, and /XREF compatibility: These options are now compatible as long as they do not have any common nodes.

•	Additional information is output for airbag reference geometry /REFSTA, /XREF, and /EREF: The starter output now includes a list of elements for each reference geometry.

•	KJOINT2 local coordinate system: The ability to define local coordinate systems for KJOINT2 element for improved support of pretension and stop distance/angles of pre-deformed joints

•	New multi-ply multi-integration point composite shell property, /PROP/TYPE51: /PROP/TYPE51 is a multi-ply shell property allowing multiple material laws types per ply and multiple integration points per ply.

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New composite shell formulation plyxfem: A new composite shell formulation based on Batoz shells using stack and ply input. Additional relative interply displacement degrees of freedom between each ply has been added to the traditional Batoz shell element. The delamination (Modes I, II, III) in each interply can be simulated by this new plyxfem formation. This formulation is considered a beta feature in this release.

•	Orthotropic material element reference direction for each shell: Each shell element can have its own material element reference direction specified which is similar to OptiStruct.

•	Multiple Layers for parts using /MAT/LAW58 (FABR_A) with /PROP/TYPE16 (SH_FABR): Parts modeled using /PROP/TYPE16 (SH_FABR) can now have multiple layers through the thickness (N> 1).

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Global material for composites when using /PROP/TYPE17 (STACK) and /PROP/TYPE51: Similar to /PROP/TYPE11 (SH_SANDW), RADIOSS automatically calculates a global material from the composite plys that is used to calculate the time step and interface stiffness. The material defined in the part is only used when viewing parts by material in pre-processing and post processing results by material.

•	Manufacturing drape simulation support: Similar to OptiStruct, a new /DRAPE input allows the definition of orthotropic material directions and thinning to be defined for each element of each ply.

•	Easier composite definition using /PLY and /STACK: Similar to /PROP/STACK and /PROP/TYPE51, the /PLY and /STACK options are used with /PCOMPP to define composites and better compatibility with OptiStruct.

Spotwelds (cohesive elements)

•	/MAT/LAW59 (CONNECT)

-	Different yield and failure stresses can be specified for tension and compression.

-	Cohesive elements can be deleted when one or more nodes become non-connected to any attached structure

•	/MAT/LAW83 algorithm improvements in the case of failure: /MAT/LAW83 now remains stable when elements are deleted thus avoiding shooting nodes.

Metals

•	Superelastic Law for Shape Memory Alloy material model, /MAT/LAW71: This law is used to model hyper-elastic materials with shape memory properties like Nitinol. It is currently only available for shell elements.

Foams and Rubbers

•	Extended stability for hyper-visco-elastic materials (LAW42, LAW62, LAW82 and LAW69): Total large strain formulation compatibility is now supported.

•	Prony viscosity compatibility for materials /MAT/LAW42 (OGDEN), /MAT/LAW69, and /MAT/LAW82: Viscous stiffness can be added to these materials by defining Prony coefficients using /VISC/PRONY. The viscous stress is added to total stress tensor in time history and animation output.

•	/FAIL/TENSSTRAIN with /MAT/LAW70 (FOAM_TAB): Element using this failure model and material will fail when maximum principal strain reaches the specified value.

•	Arruda-Boyce material law, /MAT/LAW92, to model elastomers behavior: A user-friendly input method is implemented for the Arruda-Boyce material model. Uniaxial, equibiaxial, or plane stress strain test result curves can be used in this new material model.

Cracks Propogation in Windscreens

•	XFEM and /PROP/TYPE51 compatibility: Multiple integration points per layer allows to model bending in each glass layer with higher accuracy. It is also possible to define different material types for each layer which can be used with /FAIL/FLD, /FAIL/JOHNSON, and /FAIL/TBUTCHER.

Failure Models

•	Failure from diffused necking or thinning using/FAIL/TAB1: Failure from diffused necking or thinning can be modeled by defining the Inst_start field.

•	Possibility to delete elements if failure occurs in a user-defined number of integration points

Airbags

•	Possible Starter segmentation violation when /TH/MONVOL is used with multiple /MONVOL/COMMU1

•	FVMBAG1: injectors define on an internal surface may share nodes with elements on external surface

•	FVMBAG1: In the case of an error with FVM tetra mesh initialization, the starter output will contain the tetra mesh coordinates causing the error.

•	FVMBAG1: Fixed error when using the Chemkin formulation in /MONVOL/FVMBAG1 with Avent=1.

Composites and Fabric Properties

•	Fixed issue with negative energy during high shear loading when using /MAT/HONEYCOMB, /PROP/SOL_ORTH with Isolid=17.

•	Fixed a possible core dump in starter for /PROP/TYPE17 (STACK) and /PROP/TYPE51.

•	Corrected Ish3n=30 (DKT18) SH3N shell elements which were not working if Iorth > 0 for Properties 11, 17, 51 and always for 16.

•	Improved /MAT/LAW59 (FABR_A) bending behavior

•	Improved membrane stiffness calculation for /MAT/LAW25 (COMP_SH) and /PROP/TYPE11 (SH_SANDW) with Ishell=24, QEPH elements

•	Fix animation thickness for triangles in /PROP/TYPE51.

•	Fixed crash when creating animation files when using /MAT/LAW25 (COMP_SH) and /VISC/PRONY

•	/PROP/TYPE11 (COMP_SH): wrong output of thickness and layer position when Thick value is not the same as sum of the thicknesses

Material and Failure Models

•	/MAT/LAW42: several issues corrected for shells

-	Incorrect time step calculation in starter

-	Possible instability at very high strains

-	Plastic strain results are wrong

-	Viscous part does not work

•	/MAT/LAW62:

-	Very slow in comparison to LAW42, when Prony coefficients are used

-	Possible instability with shell elements when viscosity is taken into account

-	Stability of total strain formulation (Ismstr=10) for solids

•	/MAT/LAW69:

-	Time step reported as 'Infinity' and 'NaN' in the starter output

-	Possible instability for shells

-	Possible non-physical elements deformation

•	/MAT/LAW58:

-	LAW58 and /PROP/TYPE16 in //SUBMODEL gives starter error

-	Function scaling not working in case of tabulated input

-	Improved stability in shear: results are not dependent on element anisotropic coordinate system in high shear loading

-	Results reproducibility issue when elements are deactivated

•	/MAT/LAW70: incorrect results with Isolid=1, Ismstr=11, Iframe=2; affects v13.0

•	/MAT/LAW27 and /PROP/TYPE11 (SH_SANDW): Shell stress tensor are empty

•	/MAT/LAW34: possible negative internal energy with cyclic loading

•	/MAT/LAW35: issue for unit conversion in /BEGIN card

•	/MAT/LAW2: strain rate output in animation files is null (affected versions: 13.0 and 14.0)

•	/FAIL/TENSSTRAIN : engine fails when Istrain=0

•	/FAIL/HASHIN shows strange behavior for some failure modes

•	TETRA4, Itet=3 may not work when using more than 1 SPMD Domain

•	/PROP/TYPE9 (SH_ORTH): When stress output is requested for both upper and lower surfaces, no output is exported for upper layer.

•	/PROP/TYPE22 (TSH_COMP) with elasto-plastic layers and elastic part material gives engine error

•	Corrected time step calculation for /PROP/TYPE45 (KJOINT2) elements attached to same rigid body. Previously all these joint elements provided same time step, whatever stiffness was specified in /PROP/TYPE45 (KJOINT2) card

•	/PROP/TYPE4 (SPRING) , /PROP/TYPE13 (SPR_BEAM): no softening effects when unloading parameter is set to H=6

•	/FAIL/TAB card brings segmentation error in starter when used with 14.0.220 and Single File Format

•	/MAT/LAW24:

-	Stress results sensitivity to units was reduced

-	Updated cap model

•	Possible failure if dilatancy parameters is non-zero