This document summarizes the use of topology optimization at AAM Products to reduce weight and improve performance of automotive axle designs. It describes how AAM uses Inspire and Optistruct software to perform topology optimizations that consider multiple load cases, manufacturing constraints, and target mass reductions. An example optimization of a carrier design is presented, showing a 20% mass reduction while improving gear deflection performance. The process involves defining design spaces, applying manufacturing and load constraints, setting multi-physics optimization targets, and validating optimized designs through hardware testing. Topology optimization has allowed AAM to develop manufacturable, mass-reduced axle part designs that show performance improvements.

1. Altair Technology Conference
Design Optimization of Axles using Inspire and Optistruct
May 5-7, 2015

2. 2
AAM Products

3. 3
Customers

4.  Topology Design Optimizations in AAM
 Design Optimization with INSPIRE and
Optistruct
 Case History of Using Topology Optimization
 Manufacturing Consideration
 Target setting process with Multiply load case
Outline
4

5. Carrier Optimization
Working space
Optimized ribbing design
-Use cover bolt flange to
strengthen vertical beaming
- use ribs connecting trunion and
pinion bearing area to improve
gear support
* Use Vertical Beaming and
Gear Forward and Reverse
loading with manufacturing
consideration.
* Perform Topology
Optimization Finite Element
Analysis

6. top
bottom
top
bottom
Optimization Concept and Real Design

7. New DesignBaseline Design
Baseline Carrier: 48.0 Kg New Carrier: 38.3 Kg
Optimized ribbing
design
• Use cover bolt
flange to strengthen
vertical beaming
• use ribs connecting
trunion and pinion
bearing area to
improve gear support
(patent pending)

8. 8
Gear Deflection Comparison
20% Mass Reduction
With Gear Deflection Improvement
Gear Separation Baseline Design Optimized Design
e - Vertical 0.343 mm 0.335 mm
p - Pinion axis 0.331 mm 0.324 mm
g - Gear Axis 0.098 mm 0.084 mm

9. Leakage Validation
Shear Displacement Comparison @ 2G
beaming Load
9
New DesignBaseline Design
20% Mass Reduction

10. Prototype Passed Hardware Testing
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11. Topology Optimization in AAM
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• Design improvement for NVH performance
Brown color is topology
optimized rib addition for
reinforcement

12. Topology Optimization in AAM
12
Original Design Optimized Design
Torque carrying capacity increased
three times

13. Prototype Passed Testing
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14. Topology Optimization in AAM
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Axle Design for Performance and Light Weighting
Current Cast Iron Design
12.52 Kg
Revised Aluminum Design
5.3 Kg

15. Optimization Process
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15
Design Space for Manufacturing
Process and Functional Loads
Topology Optimized Result
Interpretation and RealizationFunctional Validation with FEA

16. 16
Axle Design Out of Optimization Step
A manufacturable design
Not an abstract concept

17.  Internal gear and lubrication flow is fixed
 External Packaging space is fixed
 Stress Riser Avoidance – rib and boss connection
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Design Space

18.  Define parting line and draw direction – joint decisions with
manufacturing engineer, product engineers, CAE and CAD
 Different material requires different mesh size control in solving
 Sand Casting and Die Casting using different size control
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Manufacturing Constraints
Set maximum rib thickness
as the maximum element
size

19.  Transfer loads to bearings, bushings and
connection interfaces
 Durability requirements, Gear Loads
 NVH Stiffness requirements
 Casting requirements
 Component study with
System Boundary Conditions
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Load Consideration

20.  Critical Issues for Meaningful Optimization
 How to combine different load cases, NVH
requirements, Casting Requirements into one
Optimization Target Setting?
Target Setting
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21. Use Existing Product to setup compliance target
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Approach for Re-Designing an Existing
Product
For Inspire – adjust force levels to achieve same compliance
for different load cases
For Optistruct – Appropriately use displacement control

22.  Establish Optimization Target Range for Different Load Cases
 Displacements with full design space and without design space
 Estimate to establish Target and Design Density relationship
 With sensitivity calculation – Meaningful optimization can be
achieved in 2-3 runs
Methodology
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For Brand New Design
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23. Summary
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 AAM has developed Topology optimization
process using balanced Multi-Physics target
setting procedure with Manufacturing
considerations
 The results of Optimization process are
manufacturable designs, not just a concept
designs
 Design parts show significant mass reduction
is possible; performance improvement has
been validated through hardware testing

24. Jerry Chung, Ph.D.
Sr. Manager, Analytical Engineering
313-758-2000
Jerry.chung@aam.com
24
www.AAM.com