High-fidelity Isosurface Extraction of Topology Optimized ... · Sandia National Laboratories is a...
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High-fidelity Isosurface Extraction ofTopologyOptimizedShapes forAdditiveManufacturing
Fig 1: Marching Cubes generates triangles at eachcube/hex using the sca lar field at nodes. Fifteen uniquecases convert a hex mesh into a coarse triangulation thatmay contain high- and low-frequency noise.
1.ExtractCoarseIsosurface
Goal
Workflow
W.RoshanQuadros1,SalvatoreElder2,JoshRobbins1,BrettClark11SandiaNationalLaboratories,POBox5800,MS0897,Albuquerque,NM87185,USA.2SchoolofAppliedandEngineeringPhysics,CornellUniversity,Ithaca,NY14853,USA.
TopologyOptimization
AdditiveManufacturing
2.Refinement
Fig2:N-levelrefinement givesdesired levelofhigh-fidelity with4N triangles.O(4Nn)forN=2, O(16n)
N=0 N=1 N=2 N=3
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0 100000 200000 300000 400000
Time(Sec)
NumberofTriangles
IsosurfaceExtraction
Extract high-fidelity smooth isosurfaces from implicit data of topology optimized shapes for additive manufacturing
4.Projection
Fig 4: Steepest decent is used toproject newly inserted nodes onto isosurface using trilinearshape function
3.Stitching
Fig3:Stitch optimized (pink)andfixed(yellow)blocks
Sandia National Laboratories is a mul ti -program laboratory managed and operated by Sandia Corporation, a whol ly owned s ubsid iary of Loc kheed Martin Corporation, for the U.S. Department o f Energy ’s National Nuc lear Sec uri ty Admin is tra tion under c ontrac t DE-AC04-94AL85000. SAND No. 2011-XXXXP
6.Visualization
Results
ExplicitData:STLfile
6.VisualizeIsosurface
5.Smoothing
Thermal StructuralThermal+Structural
Marching Cubes
1-level refinement
2-level refinement 2-level refinement &curvature flattening
M (V, E, T): Surface meshf : V→ℝ3
f(Vi)n+1 = f(Vi)n + λΔf(Vi)n
∇2f= 0
Marching cubes
Δf(Vi) = –f(Vi) + |Vi*|–1 ∑j∈i* f(Vj)
0 10 20 30 40 50-20.00%
0.00%
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60.00%
80.00%
100.00%
Numberofiterations
VolumeShrin
kage%
0-levelrefinement1-levelrefinement2-levelrefinement
Fig5:Smoothing removeshigh-frequency noise Fig6:Zebrastripesindicate G0,G1, &G2discontinuity
Fig7:Lower shrinkagewith 2-levelrefinement &50iterations
1.ExtractCoarseIsosurface
2.RefinementOperation
4.ProjectionOperation
3.StitchingOperation
ImplicitData:(hexmesh withdensity field)
5.SmoothingOperation