leveraging geometric shape complexity, in optimal design for additive manufacturing
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Copyright © 2015 by Optimal Structures, LLC
LEVERAGING GEOMETRIC SHAPE
COMPLEXITY IN OPTIMAL DESIGN FOR
ADDITIVE MANUFACTURING
Yobani Martinez
Robert Taylor
Optimal Structures
2015 ATCx Conference
Houston, TX
October 8, 2015
Introduction
• Objective: Use Solid Thinking Inspire to develop
structural design concepts to leverage additive
manufacturing capabilities
• DFAM Discussion
• Case studies
• Hinge
• Upright
• UAV
• Observations
Design for Additive Manufacture
• AM enables
• Low volume (lot size of one)
• Easier design change integration (prototyping, customization)
• Piece part reductions (component combination)
• Complexity
• Geometric shape
• Hierarchical—shape complexity across multiple size scales
• Material—pointwise, layerwise
• Functional—assemblies, mechanisms
• Product performance improvement (design to match physics)
• Multi-functionality (structural and thermal and fluid and…)
Design for Additive Manufacture
• Increased geometric shape complexity can improve
structural performance (design to match physics)
• Capability to fabricate layer unrelated to layer shape
• Machining, molding operations limited by tool accessibility, mold
separation requirements
• Extreme complexity possible—mesostructures
• Lattice structures
• Load efficiency interaction
• Bending vs. Torsion
• Focus of current study
Aircraft Door Hinge Study
• Compare optimized configuration for conventional and additive manufacturing
• Requirements • Loads
• Bending
• Side loadtorsion
• Constraints • Displacement
• Stress
• Stability
• Topology Optimization • Package Space (design, nondesign)
• Objective: maximize stiffness
• Constraint: volume fraction • Conventional Manufacture (draw direction) vs Additive
Manufacture (no draw direction)
Aircraft Door Hinge Study
40% Volume Fraction 30% Volume Fraction
With draw direction—conventional manufacturing
Without hole
With hole
Aircraft Door Hinge Study
40% Volume Fraction 30% Volume Fraction
Without draw direction—additive manufacturing
Aircraft Door Hinge Study
Surface Definition using Evolve • MeshNURBS to remove data noise
• Complex surfaces—lofts, blends
New CAD Part
Conventional Manufacturing Process
• With draw direction constraint
• Total mass 6.8 lbs
Aircraft Door Hinge Study
Additive Manufacturing Process
• Without draw direction constraint
• Total mass 4.6 lbs (-33%)
Aircraft Door Hinge Study
Formula Race Car Upright Study
• Compare optimized configuration for conventional and additive manufacturing
• Requirements • Loads
• Hard turn
• x-bending
• y-torsion
• Braking
• Z-bending
• Constraints
• Displacement
• Stress
• Stability
Weight 2.68 lbs
Space 12 x 3 x 5.5 in.
Aluminum 6061
Formula Race Car Upright Study
• Compare optimized
configuration for
conventional and additive
manufacturing
• Topology Optimization
• Package Space (Design,
Nondesign)
• Objective: maximize stiffness
• Constraint: volume fraction
• Conventional Manufacture (draw
direction) vs Additive
Manufacture (no draw direction)
With draw direction—conventional manufacturing
Formula Race Car Upright Study
Volume Fraction 25% Volume Fraction 35% Volume Fraction 45%
Formula Race Car Upright Study
Without draw direction—additive manufacturing
Volume Fraction 25% Volume Fraction 30%
Min Value .9’’ Min Value .5’’ Min Value .7’’ Min Value .3’’
Formula Race Car Upright Study
Without draw direction—additive manufacturing
• 30 % volume fraction
• Max is double the min
Formula Race Car Upright Study
• Surface modeling in Evolve • Separate design,
non-design regions
• Start with polymesh cube
• Move and deform to match topology results
• Nurbify
Formula Race Car Upright Study
• Surface
modeling in
Evolve
• Import non-
design regions
• Trim, blend,
edit to get final
model
Draw
constraint
Draw
constraint
Formula Race Car Upright Study
No draw
constraint
Ongoing Work
• Size, shape
optimization
Automotive Upright Optimization
for Additive Manufacture
UAV Design Study
• Rapidly develop fuselage internal
structural configuration concept for
FDM-printed aircraft
• Thin wall structure
• Determine internal stiffening configuration
• 5 load conditions—bending about 2 axes
Wing
bending
Wing
torsion
Pitch Down
Vector
Pitch Up
Vector
Nose
landing
UAV Design Study
• Configuration
• Topology interpretation for thin
wall structure not always intuitive
• No buckling effects considered
• Sizing challenge
• Hollow members with infill
patterns
• Strength
• Stiffness
• Stability
Observations
• Inspire greatly accelerates topology optimization process
for supported modeling capabilities
• Excellent start, not final design
• Additive manufacturing enables complexity
• Geometric shape can closely match physics (load efficiency
interaction)—weight reduction
• Topology-optimized configuration requires CAD expertise—Evolve
can help
• Increases complexity of downstream shape and sizing optimization
needed to satisfy strength, stiffness, and stability criteria
top related