ICME 3GAHSS: DESIGN & CAE OPTIMIZATION OF LIGHTWEIGHT VEHICLE ASSEMBLY

- 2 engineering firms

? Two 3GAHSS steels were developed for model validation and design optimization.

? The two 3GAHSS alloys were used for:

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.

Establish Baseline Assemblies:
1. Select Assemblies
2. Load Cases and Performance Targets (Stiffness, Normal Modes, Crashworthiness)
3. Prepare Detailed FEA Models
4. Cost Model
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

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.
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

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

Max. mass saving while meeting crash performance, by
substituting 3GAHSS properties
Min. gauge assumed 0.6 mm

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

? Objective
? Mass Optimization
? Constraint
? Baseline crash and NVH targets
? Variables
? 62 Morphing points , 32 Thickness
variables, 32 Material Variables
? Job time estimate for EDAG cluster (480 CPU)
? 4.2 month @ 100% cluster utilization for
15 iterations, 189 designs per load-
case 19,845 runs for 15 iterations
? Software used
? LSOPT, LSDYNA -ICME (Explicit and
Implicit)
? Beta - ANSA ;

? 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

? 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.

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