ICME 3GAHSS: DESIGN & CAE OPTIMIZATION OF LIGHTWEIGHT VEHICLE ASSEMBLY Eric McCarty Auto/Steel Partnership. Harry Singh EDAG, Inc.

Transcription

1 ICME 3GAHSS: DESIGN & CAE OPTIMIZATION OF LIGHTWEIGHT VEHICLE ASSEMBLY Eric McCarty Auto/Steel Partnership Harry Singh EDAG, Inc. GDIS2017

2 Highlights INTEGRATED COMPUTATIONAL MATERIALS ENGINEERING APPROACH TO DEVELOPMENT OF LIGHTWEIGHT 3GAHSS VEHICLE ASSEMBLY Principal Investigator: Dr. Lou Hector Jr. (GM) 4+ Year Project - Feb. 1, 2013 Mar. 31, 2017 $8.5 Million - $6M DOE, $2.5M Cost Share 2 Participants: - 5 universities - 1 national laboratory - 3 steel companies - 3 automotive OEMs - 2 engineering firms

3 Participants Universities / National Labs Industry Consortiums Brown University FCA US LLC Auto/Steel Partnership Clemson University Ford Motor Company United States Automotive Materials Partnership Colorado School of Mines General Motors Company Pacific Northwest National Lab ArcelorMittal Ohio State University AK Steel Corporation University of Illinois at Urbana-Champaign Nucor Steel Corporation EDAG LSTC 3

4 Steel Strength Ductility Diagram Two 3GAHSS steels were developed for model validation and design optimization. 4 Steel YS (MPa) UTS (MPa) Total Elongation High Strength, Exceptional Ductility 750 1,200 37% Exceptional Strength, High Ductility 1,218 1,538 20%

5 3GAHSS The two 3GAHSS alloys were used for: Material Model Validation Forming Model Validation Design Optimization Engineering stress (MPa) Exp. (Uniaxial tension) UTS (Exp.) RVE1 ( : 57.4%, ': 25.1%, : 17.5%) UTS (RVE1) Engineering strain Phase distribution Body Side Assembly (LH & RH) 46 Stampings 5 Tempered martensite (57.4 %) Untempered martensite (25.1 %) Austenite (17.5 %)

6 Task 5 Program Requirement Baseline Assembly Applicants shall establish a baseline vehicle assembly for comparison. The baseline vehicle assembly description shall include the assembly description, its materials of construction, and weight. Baseline vehicle components shall have been available on a similarly configured 2006 or later commercially available Light Duty production vehicle. Light Duty vehicles include any of the following automobiles: passenger vehicles, light duty trucks, sport utility vehicles, or passenger vans. 6 Vehicle System Body Chassis System Definition (1) Weight Reduction Target (2) Cost per Pound of Weight Saved ($/lb saved) (2) Body-in-White, Closures, Windows, Fenders, & Bumpers 35% $3.18/lb Suspension, Steering, Wheels, & Underbody Structural Components 25% $3.11/lb Note (2) : When compared to a 2006 or Later Production Light Duty Vehicle Technologies. Additional Requirements Replacement Technology must achieve Function and Packaging Requirements of Technology to be Replaced

7 EDAG - Statement of Work Establish Baseline Assemblies: 1. Select Assemblies 2. Load Cases and Performance Targets (Stiffness, Normal Modes, Crashworthiness) 3. Prepare Detailed FEA Models 4. Cost Model 7 Design 3GAHSS Assemblies: 1. Design CAD Data 2. Integrate 3GAHSS Assemblies into body structure CAD models 3. Prepare Detailed FEA Models of body structure (LS-DYNA, NASTRAN) 4. Assess Performance and Optimize Design, using 3G (gauge grade and geometry) optimization, taking advantage of increased formability of 3GAHSS 5. Cost Model 6. Final Report

8 Baseline Vehicle & Assembly Body-side 1. Chosen Body Structure: 2008 Mid Size sedan, CAD data provided by GM 2. Several important joints and major load paths (important for stiffness and crash load cases) 3. LWB One Piece Body side inner 4. Several reinforcements in joints and members 5. LH & RH Body Side Assemblies Mass approx 100 kg (30% of BIW) 8

9 LSDYNA Model for Crash Performance 11 No Sub System Structure Mass (kg) 1 BIW Glass BIW Adhesives Door Front Left Door Front Right Door Rear Left Door Rear Right Rear Suspension Front Suspension Powertrain Steering Column IP Beam Front Seat Left Front Seat Right Hood Deck Lid Fuel tank Radiator Rear Bumper/Fascia Rear Seat System Occupants Paint / Latches / Trims /Fenders 93.4 TOTAL Crash Model System Masses Vehicle COG X Y 20.4 Z Subsystem represented as nodal masses (purple spots), constraint with interpolation constraints (blue webs)

10 LSDYNA Modeling Considerations For crash load cases, initial velocities are reduced so that the new internal energy is 70% of the total internal energy using standard regulation velocities. This is because the model is for a BIW only (i.e., not a full vehicle system model). The 30% energy reduction is a judgment based on experience with prior projects. Typical Crash System Model. All subsystems represented Pole Impact Speed 20mph For the ICME study other sub-systems are represented by lumped mass only (i.e., sub-system structures are NOT included in the CAE model). The speed is LOWERED to reduce the crash energy to achieve body structure intrusions of similar magnitude of typical Mid-Size Sedan vehicle 12 Pole Impact Speed 16.7mph

11 FMVSS214 Pole Impact 20 mph 16.7 mph Target numbers: B-Pillar Velocity & Intrusion Roof Rail / Rocker Intrusion at Impact -30% 13

12 Baseline Performance Results set as Targets CAE Load Cases 1. Side Barrier 2. Side Pole 3. Front Impact 4. Rear Impact 5. Roof Crush 1. Body Static Stiffness (Torsion / Bending) 2. Body Normal Vibration Modes 14

13 Body Side Assembly design iter-3 Max. mass saving while meeting crash performance, by substituting 3GAHSS properties Min. gauge assumed 0.6 mm Rocker Front Joint: Four Stamped Parts Body inner two thickness Laser Welded Blank Rocker Rear Joint: Two Stamped Parts 15

14 Body Side Assembly design iter-6 Increase joint stiffness by removal of panel joints Take advantage of increased formability of 3GAHSS Rocker Front Joint: Replace 4 parts with 2 Laser Welded Blank Stampings 16 Rocker Rear Joint: Improved joint iter-4 Replace 2 Parts with a Single Laser Welded Blank Stamping LWB iter-6 Rocker Front Joint: Improved joint iter-5

15 Design Iteration #3 (Gauge Reduction) Max. mass saving while meeting crash performance, by substituting 3GAHSS properties Min. gauge assumed 0.6 mm Design Iteration #6 (Combined parts) Rocker inner combined parts to increase joint stiffness Iter-3 and Iter-6 Performance 17

16 LSOPT Setup for iter-7 Gauge optimization of all parts in side assembly, sensitivity analysis 18

17 Change in Stiffness per Kg change in Mass 19

18 LS-OPT Setup for iter-8 (from iter-7) Geometry optimization 20

19 Focusing on 4 areas B-Pillar Reinforcement A-Pillar Reinforcement Inner Rocker Outer Rocker Will not change outer styling or reduce packaging space Geometry Optimization Setup 21

20 Iter-9 results 1. Meet all performance targets 2. Further mass saving limited by stiffness 3. Superior crash performance due to higher strength of 3GAHSS Results for iter-9 23

21 Objective Constraint Mass Optimization Baseline crash and NVH targets Variables 62 Morphing points, 32 Thickness variables, 32 Material Variables Job time estimate for EDAG cluster (480 CPU) Software used % cluster utilization for 15 iterations, 189 designs per loadcase 19,845 runs for 15 iterations LSOPT, LSDYNA -ICME (Explicit and Implicit) Beta - ANSA ; Final 3G Optimization - NREL 24

22 NREL HPC Setup CAE 3G Optimization required several scripts for running on the HPC Peregrine, to transport data between EDAG & HPC Proposed number of cores based on wall clock time Option 3 was approved to run on Peregrine HSC at NREL 25

23 Optimization Variable Setup for 3G Optimization 64 parts total Thickness Min = 0.55mm Max = 2.0mm Material* 10% Mn Steel 3% Mn Steel Geometry Rocker B-Pillar A-Pillar 26

24 BIW Mass (kg) kg iter9 (LSOPT baseline) Optimization Performance Body side assembly mass 67.5 kg optimized mass Cycle # 29

25 Final Optimized Model Final Model 1. Design update based on CAE optimization results, 2. MAT24 replaced with ICME User Defined 3. Single step forming 4. Manual gauge adjustment to increase mass saving 30

26 Rocker Profile Animation Baseline Optimized Top View 31

27 Process Driven - Technical Cost Modeling What it is: An objective way to compare technologies, designs or manufacturing methods An analysis of manufacturing, equipment, tooling, labor, material, and energy costs A process to identify cost drivers A method to integrate piece cost, tooling cost and capital investment. What it isn t: A precise method to obtain commercial price A business case An analysis of non-manufacturing overhead, such as prototype costs, logistics, engineering and development costs ICME Project Specific Assumption The cost estimates used are not specific to any OEM and are based on industry estimates. Specific OEMs will have varying estimates that include (but not limited to) manufacturing flexibility, safety safe-guards, regional impacts, and vehicle variant manufacturing strategy etc. 34

28 Baseline - Body Side Assembly LH Sequence Body Side Asm LH Assembly layout used to determine assembly costs based on: Number of assembly stations Number of spot welding robots Complexity of assembly station Assembly cycle time Foot print of assembly station Labor requirements per assembly station 35

29 3GAHSS Cost Estimate per kg Item # Steel Grade Reference: Cold Rolled Mild 140/270 US Spot Midwest Market Price (Avg ) (Source: Platts. Thickness (mm) Ref Grade HDG Visible Material Price ($/kg) Premium Premium Premium Min t Max t ($/kg) ($/kg) ($/kg) Tailor Rolled Coil Premium ($/kg) Tubes Straight as shipped Premium ($/kg) Multiwall Tube Blank Premium ($/kg) Tool Investmt Factor Line Rate Factor 1 Mild 140/ Reject Rate Factor 36 The average cost over 5 years ( ) per kg of steel used in the cost model for cold rolled (CR) mild steel for the US market, published by PLATTS ( 2 BH 210/ BH 260/ BH 280/ IF 260/ IF 300/ HSLA 350/ NA HSLA 420/ NA HSLA 490/ NA HSLA 550/ NA HSLA 700/ SF 570/ NA NA SF 600/ NA NA TRIP 350/ NA NA TRIP 400/ NA NA TRIP 450/ NA NA TRIP 600/ NA NA FB 330/ NA FB 450/ NA DP 300/ DP 350/ DP 500/ NA DP 700/ NA NA DP 800/ DP 1150/ NA NA CP 500/ NA NA CP 600/ NA NA CP 750/ NA NA CP 800/ NA NA CP 1000/ NA NA CP 1050/ NA NA MS 950/ NA NA NA MS 1150/ NA NA NA TWIP 500/ NA NA MS 1250/ NA NA HF 1050/1500 (22MnB5) NA NA Mn Mn

30 3GAHSS Cost Estimate per kg Premium Delta cost estimate for: 10Mn - $0.65/kg Steel Grade UTS MPa Delta ($/kg) TRIP 350/ $ 0.40 TRIP 400/ $ 0.45 TRIP 450/ $ 0.50 TRIP 600/ $ 0.55 TRIP X/ $ 0.65 TRIP Cost $0.70 $0.60 $0.50 $0.40 $ Steel Grade UTS MPa Delta ($/kg) Complex Phase Cost CP 500/ $ 0.31 CP 600/ $ 0.35 $0.55 $0.50 CP 750/ $ 0.40 $0.45 CP 800/ $ 0.45 $0.40 CP 1000/ $ 0.47 $0.35 3Mn - $0.53/kg CP 1050/ $ 0.47 CP $ 0.53 $

31 Accomplishments Baseline Design: 94.6 kg. 3GAHSS Design: 66.7 kg. Mass savings: 27.9 Kg. (-30%) Parts reduced from 46 to 28 Cost increase $ Cost per Pound of Weight Saved $0.32 / lb ($0.70 / kg) $1.26/lb $0.32/lb 38 Vehicle System System Definition (1) Body Chassis Weight Reduction Target (2) Cost per Pound of Weight Saved ($/lb saved) (2) Additional Requirements Body-in-White, Closures, Windows, Fenders, & Bumpers 35% $3.18/lb Replacement Technology Suspension, Steering, Wheels, & Underbody Structural Components 25% $3.11/lb Note (2) : When compared to a 2006 or Later Production Light Duty Vehicle Technologies. must achieve Function and Packaging Requirements of Technology to be Replaced

32 Future (2025) Class Average Weights EDAG Mass Saving Estimates 2015 Ford F Approximate Fuel saving due to Lightweighting 10%

33 Future (2025) Class Average Weights EDAG Mass Saving Estimates Further development and availability of 3GAHSS will provide an excellent economic path forward for meeting these goals 2015 Ford F Approximate Fuel saving due to Lightweighting 10%

34 Thank you The material in this presentation was possible with a lot of good feed back from all participants Universities / National Labs Industry Consortiums Brown University FCA US LLC Auto/Steel Partnership Clemson University Ford Motor Company United States Automotive Materials Partnership Colorado School of Mines General Motors Company Pacific Northwest National Lab ArcelorMittal Ohio State University AK Steel Corporation University of Illinois at Urbana-Champaign Nucor Steel Corporation EDAG LSTC 41

35 Questions? Harry Singh Director Lightweighting 1 (248) harry.singh@edag-us.com Eric McCarty Auto/Steel Partnership 1 (248) emccarty@steel.org 42 Visit EDAG s web site for more information: 3D Printed EDAG LIGHT COCOON