OpenVSP Workshop. Rob McDonald. San Luis Obispo August 20, 2014

Transcription

1 OpenVSP Workshop Rob McDonald San Luis Obispo August 20, 2014

2 Geometry as Origin of Analysis (Design) Shape is fundamental starting point for physics-based analysis Aerodynamics Structures Aeroelasticity Aerothermal / Heating Mass Properties Acoustics RCS / Signatures Packaging / Layout Manufacturing etc. Across disciplines and fidelity, shape is the common denominator. Unfortunately, there is little to no commonality in practice. 2

3 What is Geometry? What is a circle (sphere)? 3

4 What is Geometry? What is a circle (sphere)? The locus of points equidistant from a given point (x0, y0, r). A circle is an idea. Many approximate representations exist. 4

5 What is Geometry? What is a circle? What is a parameter? A labeled quantity that is familiar to deal with: Aspect Ratio Taper Ratio Thickness to Chord Ratio Some parameters are dimensions with special names. Sweep Angle Wing Span Familiar parameters correspond to canonical shapes. Circle Airfoil Wing 5

6 What is Geometry? What is a circle? What is a parameter? Is geometry a dimensioned drawing? Dimensions are parameters for arbitrary shapes. 6

7 What is Geometry? What is a circle? What is a parameter? Is geometry a dimensioned drawing? Is geometry a CAD model? CAD models arbitrary shapes. 7

8 Geometry Modeling Gap Three approaches have evolved to geometry modeling for physics-based analysis. Analysis Integrated Each code generates geometry based on its own inputs. Parametric Geometry CAD Based General-purpose CAD is used to model geometry. Prepared for analysis through grid generation and pre-processing tools. 8

9 Geometry (Mis)Representation True geometry does not correspond to analysis representation. CAD models can be built with varying (single) intent Manufacturing Represent manufacturing process, target CAM Integration & Maintenance Packaging, accessibility, etc. Structures Represent loads & load paths, target FEA Many elements do not correspond to CAD model Beam, rod, shell, plate, etc. Aerodynamics Represent OML, propulsion, control surfaces 9

10 Analysis Fidelity Holes Single model-to-analysis work flow typically developed. Fidelity selected (at least limited) by geometry model. Very little choice in analysis fidelity. Sparsely populated fidelity / discipline matrix. 10

11 Many Models Possible Representation of Geometry Shape Concept and Parameters are Geometry AR, S, Λ, λ, t/c 11

12 Representation Relates to Fidelity Vortex Lattice Panel Code CFD 12

13 Often Mistaken for Design Stage Vortex Lattice Panel Code CFD Conceptual Preliminary Detail 13

14 Phases of Aircraft Design Design phase is about what decisions are being made, not how they are made.* Phase I Conceptual Design Phase II Preliminary Design Phase III Detail Design Vs. Vs. Vs. 3 O 5 O Basic Mission Requirements Aeroelastic Requirements Local Strength Requirements Known Range, Altitude, Speed Basic Material Properties σ/ρ Ε/ρ $.lb Fatigue Requirements Flutter Requirements Overall Strength Requirements Producibility Functional Requirements Results Geometry Air Foil Type R t/c λ Δ Design Objectives Drag Level Weight Goals Cost Goals Basic Internal Arrangement Complete External Configuration Camber, Twist Distributions Local Flow Problems Solved Major Loads, Stresses, Deflections Detail Design Mechanisms Joints, Fittings & Attachments Design Refinements as Results of Test Output Feasible Design Mature Design Shop Drawings TRL Leland Nicolai, Fundamentals of Aircraft and Airship Design, AIAA, *Except where certain decisions require more advanced techniques. 14

15 Parameters Evolve Through Design Shape Concept and Parameters are Geometry True through entire design process. Conceptual Preliminary Detail AR, S, Λ, λ, t/c General Concept twist = f(η), t/c = f(η), Complex Planform, High-lift geometry, Control surfaces High-Level Finesse Detailed part designs Every Aspect Determined Design phase is about what decisions are being made, not how they are made. 15

16 Vehicle Sketch Pad (VSP) Rapid parametric geometry for design NASA developed & trusted tool JR Gloudemans Primary developer 2010 NASA Software of the Year Honorable Mention Released as Open Source Software (NOSA 1.3) January 2012 Guidelines for improvement Enable improved physics-based analysis Support design and optimization Maintain simplicity & The VSP Way 16

17 The VSP Way Intuitive, Quick, Easy First time users instantly productive Parametric geometry for design Familiar to Aerospace & Designers Wings, Fuselage, Nacelle AR, Sweep, b, t/c, etc. Real-time interactive response Sliders vary parameters Geometry updates interactively Geometry represented by cartoon Not actual wetted surface Actual wetted surface generated on command 17

18 v3 Features / Changes User Invisible Total refactor/redesign Separate Geometry, GUI, Graphics Will enable true headless versions More code re-use Less code when introducing components Entire classes of bugs eliminated Better build system New curve/surface library Single representation throughout Incompatible Changes Old scripting gone Vorview gone Rhino *.3dm gone File format change Coming Assisted parameterization VSPAero (Dave Kinney, NASA Ames) 18

19 v3 Features / Changes Done in v2 Ported to v3 Degenerate Geometry Improved CFD Mesh Design Files Many others Done Component Sets Better Symmetry Better Attachment Working Parameter UnDo Sub-surface tagging STEP Files More flexible and consistent components Advanced Users User-defined Components C++ API Python (and other script) API New scripting 19

20 Redesign & Refactor ~1992 to OpenVSP 2.X OpenVSP 3.X Geometry Geometry Subscribe to Message Passing Complex Requests & Data GUI 3D Graphics GUI 3D Graphics Headless batch/script mode Headless API access HPC Installation 20

21 AngelScript C/C++ Like Syntax Designed for integration with C++ Only has access to registered entities Built-in Scripting Custom Components User defined parameterization User defined GUI User defined geometry Batch/Script mode Access to complete API Write programs using API without dependencies Allows batch mode without complex command line Easier to maintain Advanced Parameter Linking Under development for USAF 21

22 API / Scripting //==== Test Comp Geom ====//! gid1 = AddGeom( "POD", "" );! string p0 = GetParm( gid1, "Length", "Design" );! string p1 = GetParm( gid1, "X_Location", "XForm" );! SetParmVal( p0, 12.0 );! SetParmVal( p1, 4.0 );!! //==== Test Plane Slice ====//! string slice_mesh_id = ComputePlaneSlice( 0, 6, vec3d(0.0, 0.0, 1.0), true );! Access to geometry/parameters Access to analysis/results Access to data string pslice_results = FindLatestResultsID( "Slice" );! double_arr = GetDoubleResults( pslice_results, "Slice_Area" );! if ( double_arr.size()!= 6 )! Print( "---> Error: API ComputePlaneSlice" );!! string slice_geom_results = CreateGeomResults( slice_mesh_id, "Slice_Mesh" );! int_arr = GetIntResults( slice_geom_results, "Num_Slices" );! if ( int_arr[0]!= 6 )! Print( "---> Error: API CreateGeomResults (Slice)" );!! //===== Write File With Slice Triangles ====//! if( f.open("slice_tris.stl", "w") >= 0 )! {! int num_slices = int_arr[0];! f.writestring( "solid " + "\r\n" );! for ( int s = 0 ; s < num_slices ; s++ )! {! = GetVec3dResults( slice_geom_results, "Slice_Tris_Pnt_0", s );! = GetVec3dResults( slice_geom_results, "Slice_Tris_Pnt_1", s );! = GetVec3dResults( slice_geom_results, "Slice_Tris_Pnt_2", s );!! for ( int p = 0 ; p < int(p0_vec.size()) ; p++ )! {! f.writestring( "facet normal \r\n" );! f.writestring( " outer loop \r\n" );! f.writestring( " vertex " + p0_vec[p].x() + " " + p0_vec[p].y() + " " + p0_vec[p].z() + "\r\n");! f.writestring( " vertex " + p1_vec[p].x() + " " + p1_vec[p].y() + " " + p1_vec[p].z() + "\r\n");! f.writestring( " vertex " + p2_vec[p].x() + " " + p2_vec[p].y() + " " + p2_vec[p].z() + "\r\n");! f.writestring( " endloop \r\n" );! f.writestring( "endfacet \r\n" );! }! }! f.writestring( "endsolid \r\n" );! f.close();! }! All memory maintained by VSP 22

23 User Defined Components 23

24 User Defined Components //==== Init Is Called Once During Each Custom Geom Construction =============================//! //==== Avoid Global Variables Unless You Want Shared With All Custom Geoms of This Type =====//! void Init() {!!//==== Add Parm Types =====//!!string height = AddParm( PARM_DOUBLE_TYPE, "Height", "Design" );!!SetParmValLimits( height, 4.0, 0.001, 1.0e12 );!!string diameter = AddParm( PARM_DOUBLE_TYPE, "Diameter", "Design" );!!SetParmValLimits( diameter, 8.0, 0.001, 1.0e12 );!!//==== Add Cross Sections =====//!!string xsec_surf = AddXSecSurf();!!AppendXSec( xsec_surf, XS_POINT);!!AppendXSec( xsec_surf, XS_CIRCLE);!!AppendXSec( xsec_surf, XS_POINT);! }! //==== Global Gui IDs - These Are Consistent For All Created Boxes And Used In UpdateGUI====//! int DesignTab;! int HeightSlider;! int DiameterSlider;!! //==== InitGui Is Called Once During Each Custom Geom Construction ====//! void InitGui() {!!DesignTab = AddGui( GDEV_TAB, "Design" );!!AddGui( GDEV_YGAP, "" );!!AddGui( GDEV_DIVIDER_BOX, "Design" );!!HeightSlider = AddGui( GDEV_SLIDER_ADJ_RANGE_INPUT, "Height" );!!DiameterSlider = AddGui( GDEV_SLIDER_ADJ_RANGE_INPUT, "Diameter" );!!AddGui( GDEV_YGAP, "" );! }! //==== UpdateGui Is Called Every Time The Gui is Updated ====//! void UpdateGui() {!!string geom_id = GetCurrCustomGeom();!!string dia = GetParm( geom_id, "Diameter", "Design" );!!string ht = GetParm( geom_id, "Height", "Design" );!!UpdateGui( HeightSlider, ht );!!UpdateGui( DiameterSlider, dia );! }! //==== UpdateSurf Is Called Every Time The Geom is Updated ====//! void UpdateSurf() {!!string geom_id = GetCurrCustomGeom();!!//==== Set Base XSec Diameter ====//!!string dia_parm = GetParm( geom_id, "Diameter", "Design" );!!double dia_val = GetParmVal( dia_parm );!!//==== Get The XSec To Change ====//!!string xsec_surf = GetXSecSurf( geom_id, 0 );!!//==== Set The Diameter ====//!!string xsec1 = GetXSec( xsec_surf, 1 );!!string xsec1_dia = GetXSecParm( xsec1, "Circle_Diameter" );!!SetParmVal( xsec1_dia, dia_val );!!//==== Set The Height ====//!!double ht_val = GetParmVal( GetParm( geom_id, "Height", "Design" ) );!!string xsec2 = GetXSec( xsec_surf, 2 );!!SetCustomXSecLoc( xsec2, vec3d( ht_val, 0, 0 ) );!!SkinXSecSurf();! }! 24

25 VSP To CAD Interoperability VSP Parameters AR, S, Λ, λ, t/c Fit Model Assisted Parameterization Surface Mesh Smooth Surface Export STEP Files Surface Mesh CAD Model / CFD Grid Gen 25

26 Subsurfaces 26

27 Domain Modeling 27

28 Agenda 8/20/14 8/21/14 8/22/14 Wednesday Thursday Friday 9:00 6 9:30 Welcome<&<Overview Custom<Components OpenVSP<Surface<Meshing 9: :00 OpenVSP<&<The<Design<Process VSP<to<CFD<with<Pointwise 10: :30 Introduction<to<VSP<Modeling VSP<File<Types 10: :00 GoCart<&<Cart3D<Introduction Fit<Model<Preview 11: :30 GoCart<Tutorial</<Working<w/OpenVSSubsurf,<Sets,<Symm,<Attach 11: :00 Unconventional<Design<STAR6CCM+ GoCart<w/<Adjoint<Preview OpenVSP<with<AVL 12: :30 Lunch 12: :00 13: :30 Understanding<Skinning 13: :00 USAF<SBIR<Work<Plan 14: :30 Advanced<VSP<Modeling 14: :00 15: :30 15: :00 Best<Practices<for<Modeling Lunch GoCart<Working<Session API<&<Scripting VSPAero Lunch Flightstream<Panel<Code 16: :30 Modeling<Q&A Student<Validation<Activities 16: :00 17: :30 17: :00 18: :30 BBQ<Social SLO<Farmer's<Market 28

29 Logistics Parking Restrooms Lunch / Refreshments BBQ Wednesday 6pm, Santa Rosa Park. Corner of Santa Rosa & Oak St Oak St. Farmers Market Thursday 6pm, Downtown Wireless Username: guest Password: WiFi-guest91171 (Wednesday morning only) Password: WiFi-guest74658 Presenters Please send me your presentation (PDF). Please post v2 models to OpenVSP hangar. Please send me v3 models for Wiki. 29

30 Area Map Parking Workshop Park BBQ Hotels Downtown 30

31 Questions? 8/20/14 8/21/14 8/22/14 Wednesday Thursday Friday 9:00 6 9:30 Welcome<&<Overview Custom<Components OpenVSP<Surface<Meshing 9: :00 OpenVSP<&<The<Design<Process VSP<to<CFD<with<Pointwise 10: :30 Introduction<to<VSP<Modeling VSP<File<Types 10: :00 GoCart<&<Cart3D<Introduction Fit<Model<Preview 11: :30 GoCart<Tutorial</<Working<w/OpenVSSubsurf,<Sets,<Symm,<Attach 11: :00 Unconventional<Design<STAR6CCM+ GoCart<w/<Adjoint<Preview OpenVSP<with<AVL 12: :30 Lunch 12: :00 13: :30 Understanding<Skinning 13: :00 USAF<SBIR<Work<Plan 14: :30 Advanced<VSP<Modeling 14: :00 15: :30 15: :00 Best<Practices<for<Modeling Lunch GoCart<Working<Session API<&<Scripting VSPAero Lunch Flightstream<Panel<Code 16: :30 Modeling<Q&A Student<Validation<Activities 16: :00 17: :30 17: :00 18: :30 BBQ<Social SLO<Farmer's<Market 31