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DESIGN AND ANALYSIS OF THE AUTO BODY DOORS OF THE GENERAL MOTORS CHEVROLET .RU. Project Supervisor : Professor Ahmad Barari Faculty of Engineering & Applied Science University of Ontario Institute of Technology. [email protected]. General Motors Tutor Presentation : Peter Foss. - PowerPoint PPT Presentation
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DESIGN AND ANALYSIS OF THE AUTO BODY DOORS OF THE
GENERAL MOTORS CHEVROLET .RU
General Motors Tutor Presentation : Peter Foss
Project Supervisor : Professor Ahmad Barari
Faculty of Engineering & Applied ScienceUniversity of Ontario Institute of
Technology
Team members:
Gregory Eberle, B.Eng (Team Leader)
Stephan Cregg, B.Eng
Guarav Sharma, B.Eng
Material choice – Composites Fibre Characteristics
Fibre Selection: E-glassFibre Orientation : RandomFibre volume ratio:
25% outer door panel (Grade A SMC) 40% inner door panel (Structural SMC)
Critical fibre length: 0.8625 mmChosen fibre length: 25 mm (over 30 times lc)Fibre diameter = 15 microns (between 20-150 times
smaller than lc)
Sheet Moulding Compounds
Composition Grade A SMC formulation
ResinFiller Additives – Initiators,
Inhibitors, ThickenersFiber
Processes• Compounding• Moulding
Door Auto Body CAD Design
Front Door
Butterfly Hinges
Original Equipment Manufacturers (OEM) Hinges
Impact Beam15° from the horizontal
Finite Element Models
Frame Rigidity Test
Vertical Displacement Test
Geometry #1
Geometry #2
CAD model use for FEAUsed portion of door to eliminate computational shortfalls
2 ribbing geometriestest based on various
quantities
Finite Element Analysis Results
Steel = 3.26 kgOptimized SMC Geometry = 1.34 kg40% reduction in weight!
Steel = 7.31 mmOptimized SMC Geometry = 19.19 mm
Steel = 35.29 mmOptimized SMC Geometry = 21.17 mm
Conclusion: SMC is extremely competitive with steel.
The # of ribs chosen, 35 ensures a FoS of > 2.5
Cost to Manufacture 38 ribs = $1235 CDN
Vertical displacement test
Frame Rigidity Test
Rigid Body Transformation
Determine overall door movement based on Hinge deformation
Euler Parameters including Alpha, Beta and Gamma angles
FEA AnalysisRight Angle TrianglePoints of Pressure
Rigid Body Transformation
Co-ordinates from CAD file
Matrix Manipulation Portion of Matlab Code
Results
n= 3 %^number of Original pointsOP(:,1)=[-Portion of MatLAB CodeOP(:,2)=[-3 15.5 32.5];OP(:,3)=[-3 23 32.5];
DV(:,1)=[0.022071 -0.026075 0.006052];DV(:,2)=[0.017249 -0.025916 0.005559];DV(:,3)=[0.012483 -0.025689 0.005207];
Rigid Body Transformation (Results)
A = -0.0478 0.3218 -0.0150 0 0.8277 0.5306 0.0225 0 0.8277 -0.6161 0.0320 0 -0.0479 -0.4429 0.0288 0 0 0 0 1.0000
B = -0.0478 0.3218 -0.0151 -0.0092 0.8278 0.5305 0.0216 0.0006 0.8276 -0.6163 0.0319 0.0304 -0.0480 -0.4429 0.0291 0.0108 0 0 0 1.0000
Impact Beam Design
Designs Analyzed:
Impact Beam Testing
FEA Testing Procedures: Optimization of wall thickness (≈3.175mm) (σy x FoS) vs. Mass (@ 1.3kg; 1.6kg; 1.9kg; 2.2kg;
2.5kg) MOI vs. Mass (@ 1.3kg; 1.6kg; 1.9kg; 2.2kg; 2.5kg)
Constraints and Assumptions:• FoS ≥ 3.0 (Reported Industry Standard)
σy/ FoS >σvon
• Maximum allowable displacement: Based upon 95th percentile of adult population’s sitting hip breadth δmax=14.35 cm
• Impact beam length = 600 mm
Testing Results
Optimization of wall thickness:
(σy x FoS) vs. Mass:
Impact Beam Design Displacement (Magnitude; mm)
Stress (Von Mises; kPa)
Factor of Safety(FoS)
Square 1.823e+000 3.819e+005 3.1Square with Rounded Edge 2.214e+000 4.702e+005 2.5Square with Angled Edge 2.208e+000 4.655e+005 2.5I-Beam 1.685e+000 3.629e+005 3.2Tubular 2.332e+000 4.564e+005 2.6
Statistical Error [(1.0 – R2)/R2]*100%Square 0.79%
Square Round 11.2%I-Beam 2.0%Tubular 0.64%
Testing Results (cont.)
MOI vs. Mass:
Impact Beam Selection: Square and I-Beam (extremely close) Final selection criteria is to be based upon
manufacturability and associated costs
Statistical Error [(1.0 – R2)/R2]*100%Square 1.4%
Square Round 0.21%I-Beam 1.8%Tubular 24.1%
Test & Prototyping
Ideas for test plan i.e. Prove viability of ribs
Load
String
structure with ribs
Ends are fixed
Load
String
structure with ribs
http://www.uoit.ca/EN/featurestories/connect/2009/366254/20090429.html
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