OMIS 661 Presentation – Intelligent System Case
Caterpillar uses optimization to reduce structural
mass while improving structural strength
Presenters – Celeste Latham and John Kearsing
OMIS 661 Presentation – Intelligent System Case
Agenda
•Concept Introduction
•Structural optimization
• Terminology
• Optimization process
• Caterpillar’s Virtual Product Development position
• Optistruct demo
• CAT optimization
Agenda
OMIS 661 Presentation – Intelligent System Case
Concept Introduction
Structural optimization is an automated technique that derives the
optimal design of a structure given design criteria.
Structural optimization has the potential to:.
–Significantly reduce material costs by optimizing structural designs with
respect to specified goals
–Accelerate product development through the elimination of manual design and
analysis iterations
–Improve product quality and reliability by promoting early and frequent analysis
of structural strength and life
OMIS 661 Presentation – Intelligent System Case
Material optimization Terminology
Topology optimization
Shape optimization
Optimal material layout in
a given package space
Optimal Shape of a
given geometric feature
Parametric optimization
Size optimization
Ex. Gage thickness, Beam
sections etc
Concept Introduction
OMIS 661 Presentation – Intelligent System Case
Concept Introduction
Structural Optimization Process
Topology
Optimization
Size & Shape
Optimization
engineer
engineer
engineer
Different
Iterations
Final Design
Design Interpretation
Intelligent System
Intelligent System
OMIS 661 Presentation – Intelligent System Case
CAT & VPD
A Fortune 100 company, Caterpillar is the world's leading manufacturer of
construction and mining equipment, diesel and natural gas engines and
industrial gas turbines. The company is a technology leader in construction,
transportation, mining, forestry, energy, logistics, electronics, financing and
electric power generation.
Key company facts :
• ~$23,000,000,000 company
• ~69,000 employees
• Averages 500 patents per year
• Over 1000 PhDs/CEO PhD
OMIS 661 Presentation – Intelligent System Case
CAT & VPD
• Every component on a CAT tractor is modeled in a 3D modeling
system prior to creation – Millions of models. This has set the stage
for Caterpillar’s Virtual Product Development Strategy.
OMIS 661 Presentation – Intelligent System Case
CAT & VPD
VIRTUAL PRODUCT
DEVELOPMENT
• More time spent in the early stages of virtual product development
to better reduce time spent maintaining the product in the later
stages.
OMIS 661 Presentation – Intelligent System Case
VIRTUAL PRODUCT
DEVELOPMENT
Product definition
Concept
Detailed Design
Testing
CAT & VPD
OMIS 661 Presentation – Intelligent System Case
CAT & VPD
VIRTUAL PRODUCT
DEVELOPMENT
• Structural Optimization is one focus of VPD
• Caterpillar is using Optistruct, a product developed by Altair
Engineering, to help achieve the goals of VPD
Optistruct Demo
Topology Optimization
Radiator Bracket – Design Package Space
▲ Original bracket failed
▲ Reduce stress in bracket
Courtesy TECOSIM GmbH, Ruesselsheim
Topology Optimization
Radiator Bracket – Optimization Results
Courtesy TECOSIM GmbH, Ruesselsheim
Topology Optimization
Radiator Bracket – Geometry Extraction/Design Interpretation
VOLUME = 0.3
Density Threshold = 0.6
Courtesy TECOSIM GmbH, Ruesselsheim
Topology Optimization
Radiator Bracket – CAD Detailing of Concept Design
Courtesy TECOSIM GmbH, Ruesselsheim
Topology Optimization
Radiator Bracket – Final Detailed Design
Design from Optistruct
Final Interpreted Design
Courtesy TECOSIM GmbH, Ruesselsheim
Topology Optimization
Radiator Bracket – Design Validation
Original
Design
Max. v. Mises Stress
Optimized
Design
Max. Displ.
Mass
Courtesy TECOSIM GmbH, Ruesselsheim
Optimization of SUV Chassis Frame
Optimization Objectives:
Re-design the Chassis Frame
Minimize the Mass
Maintain the same structural
stiffness
Optimization of SUV Chassis Frame
Topology Optimization
Identify the maximum design
space
Optimization of SUV Chassis Frame
Topology Optimization Result
Optimal Placement of Material
Optimization of SUV Chassis Frame
Evaluation of topology optimization result
First Concept Design
Optimization of SUV Chassis Frame
Analysis of First Concept Design
300
150
100
50
0
Concept 1
200
Baseline
Mass (kg)
250
Optimization of SUV Chassis Frame
Topology Optimization of First Concept Design
Cross-member
Topology optimization on shell
structure:
Open C-Section
Re-define Material Placement
Closed C-Section
Optimization of SUV Chassis Frame
Second Concept Design
Cross-member
300
150
100
50
Closed C-Section
0
Baseline
Mass (kg)
200
Concept 2
-12%
250
Open C-Section
Lighter Structure
Optimization of SUV Chassis Frame
Optimal Design
300
150
100
50
Baseline
Mass (kg)
200
Final
-23%
250
0
Design tuning using shape
and size optimization
Optimization of SUV Chassis Frame
Designs Comparison
Baseline Frame:
Optimized Frame:
Ladder Frame Design – 226 kg
Lightweight Concept – 174 kg (-23%)
Topology Driven Vehicle Concepts
● Lightweight SUV Frame Concept
– Baseline frame used for stiffness and modal targets
●
●
Including Torsion Bar & Trans C/M
Mass: 498(lbs) [226(kg)]**
●
** Includes
mass of welds (3kgs)
Performance Targets:
–
–
–
–
–
Twist:
Vertical Bend:
Lateral Bend:
Bending Stiffness:
Torsion Stiffness:
Target Weight Reduction 125lbs (25%)
18.7 Hz
27.1 Hz
29.0 Hz
3278 N/mm
121 kNm/rad
Topology Driven Vehicle Concepts

Define all available package
space, Loading, and BC’s

Topology Optimization for gross concept features


Interpret into first concept design
Topology optimization for concept
refinement
 Interpret concept for final optimization and
design details
Concept Development Process
Final Concept
Topology Driven Vehicle Concepts
●
Final Concept Design
–
–
–
–
–
–
–
Primary Hydroformed Sections
Mid-Rail “C” Section
Welded Body Mount Brackets
23% lower mass
25% fewer parts
50% less weld length
Cost penalty:
• $0.25 cost per lb saved
●
Performance Results:
–
–
–
–
–
Twist:
Vertical Bend:
Lateral Bend:
Bending Stiffness:
Torsion Stiffness:
25.0 Hz (+34%)
27.8 Hz (+2.5%)
26.4 Hz (-9%)
3278 N/mm (0%)
159 kNm/rad (+31%)
OMIS 661 Presentation – Intelligent System Case
D8 Trunnion optimization
CAT Optimization
OMIS 661 Presentation – Intelligent System Case
CAT Optimization
Original Fabricated Trunnion Design – 2 pieces
Fabricated Version: Mass=44.1 Kg
OMIS 661 Presentation – Intelligent System Case
Design Objective
Minimized Weight
Design Constraints
Von Mises Stress (Yellow Part) < 785 Mpa
Max Principle Stress (Yellow Part) < 372 Mpa
Design Variables-Five
•Inside pocket
•Neck Radius
•Neck Transition
•Bolt Plate Thickness
•TRF Inserted Flange Thickness
CAT Optimization
OMIS 661 Presentation – Intelligent System Case
Final Design
CAT Optimization
Weight Results
weight
45
40
weight
35
30
25
Current
Optimized
Weight(kg) % Reduction
CURRENT
FABICATION
DESIGN
44.1
OPTIMIZED
DESIGN
26.6
39.70%
OMIS 661 Presentation – Intelligent System Case
CAT Optimization
Stress Results
Requirement: Max Principle Stress < 372 MPa
Result: 187.9 MPa
Requirement: Von Mises Stress < 785 Mpa
Result: 757.3 MPa
Max. Load
OMIS 661 Presentation – Intelligent System Case
CAT Optimization
Financial Results
• 40 % weight reduction from current production design
• $136 cost savings per a part
• 3260 parts are expected
• $443,360 annual cost savings
OMIS 661 Presentation – Intelligent System Case
Future Uses
•Expand the optimization process other product lines
•Gain an estimated savings of $2 million in 2005
CAT Optimization
OMIS 661 Presentation – Intelligent System Case
Questions?
CAT Optimization