## PERMAS Version 16 New Release

### PERMAS

#### Direct I/O

• V16 supports direct I/O to SSD systems:-io direct option of the permascommand.

• Link of disks via PCI Bus instead of I/O controller.

• Interesting for I/O bound jobs and for servers with several simultaneous computation jobs(throughput).

### Interface

#### DOOR

Abaqus

• Translation adapted to new PERMAS feature, e.g. for contact and gasket modeling

• Support of connector actuation definitions

• Extended user controls for model translations (DEFAULT SET ABAQUS)

•VisPER interaction with messages and overview tables

MEDINA

• MEDINA 9.0 support

NASTRAN

• CPYRAM supported

#### Export

• Export of stresses much faster (e.g. to Medina).

• New EFREQMOD uci/dat commands for Excite

• Nastran OP2 output (partially) supported

• for PERMAS V16 new binary result format.

– Based on HDF5-library. Hence, general access is quite simple.

Python integration,simple viewer like hdfview for TOC,...

– Against BOF-export further accceleration and no BOF restrictions on model size limits.

– VisPER, permasgraph support.

#### Export,HDF

• Example: 150 000 Nodes, 1000 Modes; Shell model (Standard disc, striped) Export Elapsed

1. For fast I/O systems, compress is expensive

2. More I/O for Medina export due to:

• Different storage in PERMAS and Medina

• Concatenation of BOF file due to parallel write

### General Functionality

#### $DISLOADX: Hydrostatic Pressure

##### Tank with internal hydrostatic pressure load

$DISLOADX HYDROPRESS LPAT=101 RSYS=1001 AXES=-3 LDEF=SURFACE

TANK_SURF ACCELERATION=9.80665 FLDENS=0.8E+3 CPRESS=2.0E+5 PREF=43751

!

! Doubly wetted wall

$DISLOADX HYDROPRESS LPAT=501 RSYS=1005 AXES=1 LDEF=ELEMENTS

ESET_WALL ACCELERATION=9.80665 FLDENS=1.0E+3 PREF=301

& : ACCELERATION=9.80665 FLDENS=1.0E+3 PREF=654

#### New $SURFACE Options

• MIDNODE = DEPENDENT as simple alternative to $MPC ISURFLIN

+ no additional lines (only 1 surface definition needed)

+ all surface parameters (incl. SFSET) for linear surface, too

+ independent of local DOF directions (ROTB independent)

+ automatic DPDOF=1[,2,3] setting (can not be mistaken)

+ automatically valid for all DOFTYPEs (DISP, TEMP, etc.)

+ with contact pressure – no extra plot elements needed

+ save against ’multiple dependencies’ (edges,pretension, etc.)

+ Default preset via UCI switch SFMIDNODE

• New UCI switch:SFPRINT

Print surface verification(#Nodes,Area,etc.)

• New export ITEM:SURFACE DEFINITION

• Fully supported in VisPER

#### MPCs

• DEPCOOR=PROJECT option for ISURFACE MPC

Enables the modification of dependent node coordinates (instead of rigid lever arm)

• ISURFLIN now supports SFSET, DOFTYPE and a combination with further MPCs

• New UCI DEFAULT option: MPCUPDATE = COEFF

For an automatic re-computation of the MPC coefficients for: NLGEOM= YES.

• Improved rigid lever arm correction for curved surfaces.

• WLDSURFACE also supports solid shells.

#### $RSYS Extensions

#### FORM Option for $RSYS CART

#### FORM Option for $RSYS CYL

#### FORM Option for $RSYS SPHER

#### New $RSYS GEOS - Geospherical System

#### New $RSYS CONE - Conical System

#### New $RSYS TOR -Toroidal System

Nearly all roundings at shafts/drillings, bearing surfaces, roller bearings and crowings of rolls are torus faces..

#### ROTB with Euler Angles

$ROTB RSYS=17 EULER=3,45.0 1,15.0 ! RSYS 17 plus successive Euler

HELICAL_GEARNODES ! rotations around z’ and x’’

#### New $MATREF Projection

• More convenient handling of material system orientation for 2D elements.

• Projection of local system definition onto element surface.

• X-axis of local system may not be collinear to element normal.

#### New $PRETENSION Options

• TEMP = JOIN/FREE option. Automatic coupling for: DOFTYPE TEMP.

• GUIDING = SUPPRESS Internal support by a SUPPRESS statement.(fix connection without prestressing force).

• Rigid lever arm correction analogous to $MPC ISURFACE/ILINE.

#### New $PRESSFIT

• Press-fit as pure MPC coupling – without any CA-DOFs !

• Permanent coupling with load variable interference,

i.e. overlap = f (LPAT & $NLLOAD).

≈ Prescribed $MPC ISURFACE in surface normal direction.

• Works for static & dynamic analyses (e.g. pre-stressed modes).

• Also applicable in sub-structures.

• Specific results for: Verification, Precheck and Calculation available

#### $PRESSFIT versus $CONTACT

$PRESSFIT benefits compared to contact definition:

• Permanent coupling

– Works for all analyses (static & dynamic), e.g. no $CONTLOCK needed

– Also applicable in sub-structures

– Connected mesh (no extra RBM-Springs or CAZERF-Elements needed)

• Faster run-time (no flexibility, no contact DOFs, no iteration needed)

• Runs without CA/CAX licence

$PRESSFIT restrictions compared to contact definition:

• Permanent coupling: Can not open/close, i.e. always active - completely !

(use sign of ITEM PRESSFIT FORCE to detect unintentional ’passive’ areas)

• MPC coupling restrictions:

– Dependent DOFs and autogenerated ROTBs (similar to $PRETENSION)

– No surface-to-surface coupling (similar to $PRETENSION)

– Same node can not be part of two pressfit definitions

– Pure geometric constraint (overlap), i.e. no FORCE option

• No geometry update with CAU & NLGEOM=yes (similar to $PRETENSION)

• No contact pressure result (but ITEM PRESSFIT FORCE [VECtor])

#### Elements

• Improved stress computation for (bad shaped) HEXE8 elements. New default in V16.

• Improved co-rotational formulation for shells/beams. Improved convergence for larger geometry changes.

New default in V16.

• Improved pressure stiffness computation for LOADA4 element.

• Extended set of parallel element processors.

#### New $FUNCTION VOXEL

• Function values on a (regular) 3D data grid for$PREVAL evaluation.

$FUNCTION VOXEL FID=30 GRID=4,3,4 VSIZE=1.0 ORIGIN= 0.5, 0.5, 0.5

:3 2 3 51.0:

• Data input defined at voxel center.

• “csv” input for ADSTEFAN casting simulation interface.

#### Sampling extensions

• General functionality to perform parameter studies. See also CLOOP command.

• New option for $VPARVAL command: INPUT = LOG

Creates a logarithmic distribution, i.e. for rotordynamics applications.

• New option for UCI SAMPLING command: METHOD = LHC to perform a (nonuniform) latin hypercubesampling.

### Modules

#### NLS

• NLMATERIAL and BUCKLING analysis in a joint task loop. I.e.

perform a linear buckling analysis at each converged load step.

• SUMLOAD and SUMREAK available for nonlinear analysis.

• Cutting force summary available.

• New DEFAULT MPCUPDATE = COEFF option. For an automatic update of MPC coefficients forNLGEOM = YES.

• New DEFAULT option: SHELLTYPE, to perform an automatic switch from linear shells to solid shells (= SOLID).

• Hydrostatic pressure load and $VELOSTATE supported.

#### Material-and geometric nonlinear Analysis

#### Large Displacements

#### PERMAS CA[X]

• CAGEO as new default for CARESULTS-switch (instead of CANODE), e.g. by default no “zero gap”-result on surface-side.

• Improved CASO re-use for contact with friction.

• $CONTLOCK with CASFILE now also for FRICTION=MATRICES & limit conditions MINFORCE/MINFRICF/MINPRESS/MINSHEAR.

• CA-status on surface-side without -0.5 shift (same value as primary status). Plus: New UCI-switch CASURFST=ON/SHIFT/OFF (old CASURFST now as CASURFMSR)

• Auto-ignore of CAZERF elements for situations without CA-iteration.

#### PERMAS CA[X] Gasket-2.0

#### PERMAS CA[X] COMPLEMENT

• COMPLEMENT option for SURFACE-to-SURFACE contact (and UCI switch CASCOMPLEMENT).

– Automatic adaption of the CA discretization to meshsize variation(mutual coarse/fine).

– Better than S2N (especially at border area) but much less CADOFs than S2S −→ nearly S2S-quality with S2N-runtime.

– New UCI-Switches CASURFMSR and CASCOMPANGLE

#### PERMAS CA[X] Center of Pressure

#### $CONTACT LOAD Gap Function

#### Dynamics

• Craig-Bampton reduction for: Rotational and gyroscopic stiffness

• Von Mises stress for steady-state analysis

• New complex eigensolver (parallel)

• Inertia relief attachment modes: RBMINERTIA option for $ADDMODES

(Default switch MLDRADDM = ON)

• MLDR – Faster CB mass and damping reduction

– Damper elements automatically in top component

– Sets provided in top component

– $COMMENT available

– $ELSTATE TEMP available

– Assembly situation and addmodes available

– Improved filter for PRIMRES = REDUCED

– Improved selection of eigenvalue solver

#### Frequency Response

• SOLV = SMW Option for MODAL FREQUENCY

– Motivation: For models with many eigenvalues,many excitation frequencies, and only some dampers the computation of the frequency responseis expensive.

– Solution approach: As long as the dampingis not frequency dependent

(only a few discrete dampers), a diagonalisation of the system is possible via a single value decomposition(complex eigenvalues).

An explicit inversion of the resulting system matrix may be performed, applying the Shermann-Morisson- Woodbury SMW formulation.

The subsequent computation of each frequency point is cheap.

#### Direct fluid time history analysis

#### Direct FSCoupled Frequency

Significant acceleration

V14 −→ V15 −→ +XPU −→ V16

Direct Frequency Response for coupled

Fluid-Structure (11.2 Mio DOFs)

on 16 core (2∗E5-2680) plus Tesla K20c

### Optimization general

#### 'Combined' Optimization

• Arbitrary combination of topo-sizing-shape variables possible.

• UCI-commands OPTIM and TOPO execute identical solution steps(only different parameters).

• Great variety of new problems solvable.

• Required functional modules depend on design variables types.

#### Topology and Shape Optimization

• Cylindrical shell model with single load

• Simultaneously shape and topo in same domain

• Goal: Maximum stiffness with mass limit

#### Topology and Shape Optimization(2)

#### Example 2

• Topology optimization

• Beads

• Variable sheet thickness

#### Restart for optimization

• Motivation: Accelerate the optimization process for model variants

• Approach: Output of the internal design variable state for the initial run and import state for the variant

• Applicable for all optimization types

• Hint: Do not use final states for topo-variables (0-1 fill iteration)!

#### Non-Parametric Shape

• New solver for optimality criteria problems with additional constraints.

• Improved handling of stresses as constraints (not as target).

• DCLINK support with NPSTRESS constraints.

• Elementtestconstraint available with improved formulation.

• NPEFFPLSTRAIN constraint (nodal point eff. plastic strain).

• $DCONSTRAINT NPSTRESS: maximum principal stress selectable.

and new PRST (prin. stress) constraint.

• Improved default filter.

• New (2-step) relaxation algorithm.

• Improved wizard in VisPER.

#### (Topology-)Optimization

• Topology Optimization with multiple materials

• DERESTRAINT TYPE = FREEZE; Improved freeze condition and option to handle more than one material

• Improvements for two-sided release direction.

• New DCONSTRAINT FILL.

• New DVTPAR KIND=GENERAL option to apply a function for material property to filling ratio dependency

• New DVTPAR KIND=GEODAT for free sizing of geometrical properties (e.g. sheet thickness)

• Restart for topo.

• XYDATA TYPE = RHIS

with relative constraint value history for easier evaluation.

• Reduced computation of secondary results, restricted to DCONSTRAINT references.

Omit GEN commands in task loops.

#### Performance,Frequency Resp. Opt.

• Topo: Statics and frequency response

• 3 Mio. elements, 6 Mio Dofs

• 33 Task loops

• Improvements:

– Faster frequency response derivative computation

– Faster boolean transformations

– Filters on computation of requested design constraints

### Optimization, new Algrithms

#### Multiple Design Objective

• V15: One design constraint has to be selected as design objective.

• V16: An arbitrary number of design constraints may be declared as design objective.

The maximum value will be minimized, whereas all others are constraints (with a dynamic upper limit).

#### Pareto Optimization

• If several optimization goals exist, a trade-off of design decisions may be important.

• The pareto front defines the limit state where it is not possible to further improve a goal without violating another one.

• With the $PARETO SAMPLING command in PERMAS V16, a pareto optimization may be performed. It provides a sampling capability of the pareto front with fixed step size. Only this command is needed to change from a single objective to a multi-objective design optimization.

#### Example, OP11 Varient

• Target weight minimization

• Upper stress limit declared as multi objective target

#### OP11 Variant, Pareto Front

#### Global Design Centering

• Task: Search for a domain with maximum stability.

• Design centering solution as sphere with maximum diameter (2d-circle)

• Example application: Brake squeal analysis with stochastic parameters for brake pad material

• Selection in OPTIM command by:OPTIM dsmethod=none method=GDC

• Global algorithm.No local termination criterion, the given number of task loops is being performed.

• Histories allow to check the center point, no further usage.

• Informations such as approximate size of feasible region, center point and diameter in RES-file.

• Boundary of stable region visible as blue line.

#### External Tools for Optimization Cycles

• New UCI command: EXTSOL to use an external “solver”.

• Result import via: $DATA NPUSER .

• Mechanism to build simulation and optimization process chains.

• For model completion, see e.g.: FreeWizard in VisPER.

#### PERMAS-FEMFAT Coupling

• Freeshape optimization, piston rod

• OC-Method (no derivatives)

• FEMFAT for durability

#### Optimization, solver and constraints

• METHOD=ACP as new Option for OPTIM/TOPO commands

– Adapted Convexity Programming solver

– Out-of-core (and parallel) algorithm for large optimization problems

– Recommended for nonlinear behavior and/or complex manufacturing conditions

• $DSVMLIM support for AOS methods: SCP,SLP,SQP

• New/extended $DCONSTRAINT Options:

– REACD for reaction forces at dependent nodes (e.g. pretension force)

– NPSTCOMP nodal point stress tensor components

– PRST for principal stress

– New option SET for WEIGHT constraint.

• Design variable sets as argument in $DCFUNCTION.

• New design element DNODE to integrate external SBV without DFREE relaxation.

### Summary

• Broad spectrum of new features in V16

• Support for complex workflows

• A lot of new optimization capabilities

• Some features already visible on industrial applications

• For an efficient use, we offer upgrade workshops

**We are curious on your feedback**

Thank you for your attention