1. Copyright © 2015 by Optimal Structures, LLC
STRUCTURAL COMPONENT DESIGN
OPTIMIZATION FOR ADDITIVE
MANUFACTURE
Robert Taylor
Yobani Martinez
Tim McCloskey
2015 Americas Altair Technology Conference
May 6, 2015

2. Introduction
• Objective: Use Solid Thinking Inspire to develop
structural design concepts to leverage additive
manufacturing capabilities
• DFAM Discussion
• Case studies
• Hinge
• Upright
• UAV
• Observations

3. Design for Additive Manufacture
• AM enables
• Low volume (lot size of one)
• Easy 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…)

4. 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

5. Aircraft Door Hinge Study
• Compare optimized configuration for conventional
and additive manufacturing
• Requirements
• Loads
• Bending
• Side loadtorsion
• 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)

6. Aircraft Door Hinge Study
40% Volume Fraction 30% Volume Fraction
With draw direction—conventional manufacturing
Without hole
With hole

7. Aircraft Door Hinge Study
40% Volume Fraction 30% Volume Fraction
Without draw direction—additive manufacturing

8. Aircraft Door Hinge Study
Surface Definition using Evolve
• MeshNURBS to remove data noise
• Complex surfaces—lofts, blends

9. New CAD Part
Conventional Manufacturing Process
• With draw direction constraint
• Total mass 6.8 lbs
Aircraft Door Hinge Study

10. Additive Manufacturing Process
• Without draw direction constraint
• Total mass 4.6 lbs (-33%)
Aircraft Door Hinge Study

11. 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

12. 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)

13. With draw direction—conventional manufacturing
Formula Race Car Upright Study
Volume Fraction 25% Volume Fraction 35% Volume Fraction 45%

14. Formula Race Car Upright Study
Without draw direction—additive manufacturing
Volume Fraction 25% Volume Fraction 30%

15. 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

16. Automotive Upright Optimization
for Additive Manufacture
Draw
constraint
No draw
constraint
Draw
constraint
Formula Race Car Upright Study
No draw
constraint
Ongoing Work
• CAD update
• Size, shape
optimization

17. 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

18. UAV Design Study
• Ongoing work
• Configuration
• Topology interpretation for
thin wall structure not
always intuitive
• No buckling effects
considered
• Sizing
• Strength
• Stiffness
• Stability

19. 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