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.
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
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
14. Topology Optimization in AAM
14
Axle Design for Performance and Light Weighting
Current Cast Iron Design
12.52 Kg
Revised Aluminum Design
5.3 Kg
15. Optimization Process
15
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
17
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
18
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
19
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
20
21. Use Existing Product to setup compliance target
21
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
22
For Brand New Design
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23. Summary
23
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