New advanced optimization possibilities within OptiStruct 13.0.x

Transcription

New advanced optimization
possibilities within OptiStruct
13.0.x
Kristian Holm
(23.10.2015)
HyperWorks Best Practice
www.altairhyperworks.de/BestPractice
Copyright © 2012 Altair Engineering, Inc. Proprietary and Confidential. All rights reserved.
Outline
• Multi-Model Optimization
• Excel Connection
• Large shape changes
Multi-Model Optimization
Multi Model Optimization
Multi Model Optimization (MMO):

Multiple optimization models in a single run

Common design variables are required

Greater flexibility to optimize common components across structures

Existing models can be used without modification
Two separated models which have a
commonly defined portion of the
design domain (in green)
Multi-Model Optimization – Use Cases
• Similar models with different meshes (e.g.
coarse and fine)
• Similar models with subcase-dependent
configurations or characteristics (e.g.
damping)
• Different models sharing identical designable
parts
• Different models connected at designable
locations
• Different models with combined objectives or
constraints
W1
W2
• Any combination of the above
min (W1+W2)
Multi-Model Optimization – Setup
• Implemented within a MPI-based framework (SPMD parallelization)
• Conceptually, optimization only necessitates the knowledge of the underlying
mathematical problem, hence the simplistic overview:
• One master process handles the optimization tasks
• Slave processes handle the analysis and sensitivity analysis tasks for each model
• Processes exchange design variables, responses and sensitivities
• Several MPI implementations are supported (Intel MPI, Platform MPI, Microsoft MPI, etc)
on each platform
• Launched from the solver script or from the run manager GUI
optistruct –mmo [MPI_TYPE] –np [N] [MASTER_DECK] [OS_ARGS]
• Number of processes must be equal to the number of models plus one
• Initiated through the so-called “master” or “setup” input deck
• Lists the models to include in the multi-model optimization
ASSIGN,MMO,<MODEL_NAME>,<INPUT_DECK>
• Optionally contains limited control cards and bulk data cards
Multi-Model Optimization – Design Variables
• Sizing and shape design variables
• Design variables (DESVAR) with identical IDs are linked together
• Dependent design variables (DLINK) are supported
• Discrete design variables (DDVAL) are supported
• Covers properties (DVPREL), materials (DVMREL) and elements (DVCREL)
• Topology and free-sizing design variables
• Design variables (DTPL/DSIZE) with identical IDs are linked together
• Similar to pattern repetition with implicit master/slave(s) relationship(s)
• Standard manufacturing constraints, such as member size control or draw direction, are
supported
• Topography design variables
• Design variables are not linked together, but topography optimization can be carried on
each model independently
Multi-Model Optimization – Objectives and Constraints
• Responses
• All existing solution sequences and response types are supported
• Global equation (DRESP2) and external (DRESP3) responses may be defined in the master
deck to combine responses originating from individual models
• DRESPM identifies the responses and models being combined
• Example: equation calculating the total mass of two models
DRESP2
+
100
DRESPM
MASS
10
SUM
MMO3P
10
MMO2P
• Objectives and constraints
• Global objectives and constraints may be defined in the master deck
• Single objectives are combined into a multi-objective formulation, with reference values
(DOBJREF) being automatically assigned based on the analysis values
• Individual models are not required to have an objective, as long as there exists at least
one objective within the combined optimization problem
• Automatic screening is supported
Multi-Model Optimization – 2D Example
Sides (SMO)
Middle (SMO)
Sides (MMO)
Middle (MMO)
Compliance
1796.97
1125.16
2703.78
1190.92
Iterations
36
58
55
55
CPU Time
2m 36s
4m 16s
5m 10s
5m 8s
Single Model Optimization
Multi-Model Optimization
• Problem definition
• 2 variants of a Van – short and long version
• Front and rear components should share same platform (concept needs to be similar for
both)
• 4 subcase (Torsion, Bending, linearized Roof-, Sidecrash)
• Results: -> HV
Excel Connection
Excel Connection - Introduction
• Motivation
• External responses can be defined through user-defined libraries (Fortran/C) or
HyperMath scripts, but many users are not proficient with those techniques
• Some Customers already rely on Excel spreadsheets to calculate responses
(e.g. custom buckling, reserve factors, failure criteria) especially in the aerospace industry
Excel Connection - Simple Definition
LOADLIB DRESP3
DRESP3
+
10
DRESP1
ELIB
SUM
5
dresp3_excel.xlsx
ELIB
6
MYSUM
• The LOADLIB card identifies the Excel workbook file
• The function field identifies the Excel spreadsheet name
• Input parameters are transferred to cells in the first column, while responses are
retrieved from cells in the second column
Excel Connection - Advanced Definition
LOADLIB DRESP3
DRESP3
+
+
+
+
+
20
DRESP1
DESVAR
CELLIN
CELLIN
CELLOUT
ELIB
FUNC
5
1
B3
C10
E10
dresp3_excel.xlsx
ELIB
6
MYFUNC
7
THRU
B6
8
• Input parameters are transferred to cells enumerated by CELLIN, while responses
are retrieved from cells enumerated by CELLOUT
• Also includes VB inside excel (can also be encrypted)
• => example
Large shape changes
Large shape changes
• Optimize configuration design, such as positioning of ribs, spot welds, which
requires large shape change at the connections.
• In OS 13.0.210, the shape sensitivity calculation are implemented for linear static
elastic problems
• Rebuild the connector elements or the contacts according to the shape update step
after each optimization iteration
Large shape changes - contactN2S
1. MinMax the stress to find the optimized positioning of the left rib
2. The two ends and inner side of ribs are connected to the frame with contact (FREEZE)
3. The DVGRID values are the same for all the nodes of left rib
Large shape changes - contactN2S
Video of shape change
Initial design
Design history
Optimized design
Large shape changes - CWeld
Beam formed
by welding two shells
1. MINMAX stress for optimized
cross-section shape
2. Fixed one end, twist the other
end
3. Design moves the flange of the
section
Cross-section view
DVGRID
DVGRID
CWELD
CWELD
Large shape changes - CWeld
Initial design
Animation
Of shape
change
Final design
Large shape changes - TIE
- Use of nonlinear shape Design Variables in order enable real rotation
- Linking of linear shape Design Variables by HyperMesh
Summary
• Multi-Model Optimization
• Excel Connection
• Large shape changes
HyperWorks BestPractice Webinare
30-minütige GoTo-Webinare in deutscher Sprache:
•Optistruct Optimierung
23. Okt., 11:00 Uhr
•HyperMesh Entity Editor
28. Okt., 11:00 Uhr
•Inspire und Evolve
30. Okt., 11:00 Uhr
•Model Checking mit HyperMesh
03. Nov., 11:00 Uhr
•Optistruct Kontakte
13. Nov., 11:00 Uhr
•Tipps und Tricks für die CFD Vernetzung
in HyperWorks 14
23. Nov., 11:00 Uhr
•Mapping von Umformergebnissen auf FE-Netze
für Struktur- und Crashsimulation
27. Nov., 11:00 Uhr
•Bidirektionale HyperWorks PowerPoint Anbindung
02. Dez., 11:00 Uhr
•SixSigma mit HyperStudy
10. Dez., 11:00 Uhr
•
Kostenfreie Teilnahme – 30 Minuten die sich für Sie lohnen
•
Anmeldung und weitere Informationen unter http://www.altairhyperworks.de/bestpractice

New advanced optimization possibilities within OptiStruct 13.0.x

Transcription

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