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VINOTH KUMAR DHANANJAYAN Thesis Defense for MS Mechanical Engineering

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Presentation on theme: "VINOTH KUMAR DHANANJAYAN Thesis Defense for MS Mechanical Engineering"— Presentation transcript:

VINOTH KUMAR DHANANJAYAN Thesis Defense for MS Mechanical Engineering April 3, 2013 Committee : Prof. Robert Woods, University of Texas at Arlington (Advisor) Prof. Kent Lawrence, University of Texas at Arlington Prof. Wen Chan, University of Texas at Arlington

2 Background & Motivation
Alternate process development of a high strength part Weight reduction Functional performance improvement Machining time reduction FORGED CARBON FORGED COMPOSITE ADVANCED COMPRESSION MOLDING PROCESS Cycle time – minutes Strength – equal to quasi isotropic LAMBORGHINI CALLAWAY Ref :, composites world

3 Objective Development of wheel center by compression molding process
Study on factors influencing the compression molding process Analysis of existing and proposed design of a part Raw material selection Mold design Thermal system identification and analysis Process parameters

4 Importance of closed mold and short fibers
Advantageous closed mold process Directional properties High process time High skill requirement Intricate shapes not feasible High part cost Low volume Open mold continuous fiber Near isotropic properties Quicker cycle time in minutes Minimal skill dependency Near net shape part and ability to mold complex shapes Low part cost High volume Closed mold short fiber

5 Minimal flow  Less fiber breakage
Compression molding Minimal flow  Less fiber breakage Ref : Duqueine, Mazumdar composites mfg, lamborghini urus

6 Compression molded parts
Ref : Hexcel, Lamborghini, Audemars piguet, Carbon Forge, Duqueine, excel sports, DUC -helices

7 Part  Material  Process
Process dependency Part  Material  Process COMPRESSION MOLDING resin type formability fiber content fillers Mold design Thermal system charge placement process temperature & pressure Press parallelism, mold finish, ejection Part strength volume Thickness variation Holes or mash off zones Moldability PART MATERIAL fiber length resin process parameters PROCESS

8 Wheel center part study
Wheel center loads Most suitable for compression molding 20% improvement yields 1.58 lbs weight saving/car Improve lateral stiffness – high deformation High machining time and material wastage Lateral Load Lateral load lb Normal reaction load lb Braking Load Braking load lb Normal reaction load lb Reaction force due to weight Braking force Ref : UTA FSAE team (load values)

9 Raw material selection
Benchmark properties – Al 6061 T6 Market study Hexcel, ten cate, Quantum composites 15 compounds Carbon epoxy and vinyl ester

10 Existing wheel center – lateral load
FOS – 0.96 Elements Equiv Stress (ksi) Change % 51831 36.4 60157 38.9 6.8 % 70013 41.1 5.5 % 93733 41.6 1.2 % Deformation – 0.049”

11 Existing wheel center – Braking load
Deformation – 0.004”

12 Inference Functional issue Moldability L Increase lateral stiffness
Strengthen riveting points Moldability Provide drafts Minimize pattern holes Gradual thickness variation L

13 Proposed design Proposed Existing Other designs studied

14 Proposed design – Lateral load
>25 % Improvement FOS – 1.48 FOS 27 % Stress 30 %

15 Proposed design – Braking load

16 Results comparison 24 %

17 Good mold design  Better part quality
Mold material - Al 6061 T6 Better machinability Quick heat transfer Better surface finish Shear edge design Complete filling Escape of air Mold size Length 15” Breadth 14” Thickness 2.5”

18 Wattage required for heating the mold in 30 min – 3.6 KW
Heating system Cartridge heaters Quantity – 4/mold Capacity – 450W Wattage required for heating the mold in 30 min – 3.6 KW

19 Heating system - analysis
Minimum temperature variation  Uniform heat absorption by charge

20 Uniform cooling  Minimum warpage
Cooling system Uniform cooling  Minimum warpage Remove heat generated during curing reaction Depends on Location of cooling lines Size of cooling lines Types of cooling lines Length of cooling circuit Flow rate of coolant Position of channels and time taken for cooling are analyzed in solidworks Best suitable mass flow rate of water selected for individual molds to have uniform decrease in temperature

21 Cooling system analysis
Minimum temperature gradient b/w mold halves  Min warpage Ref : DSM design guide

22 Mold assembly

23 Accurate control of the process  High part repeatability
Process parameters Accurate control of the process  High part repeatability Material - MS 4A Charge loading pattern – By trials during manufacturing Press capacity – 85 ton Press pressure – 2000 psi Process temperature – 150 deg C Mold pre heat time – 30 min Heater bore clearance – mm Cure time – 20 min Press parallelism – 0.001”/ft (recommended values)

24 Future Scope Process simulation Software simulation to predict
Fiber orientation Charge pattern Warpage Closing speed Material flow Software Moldex 3d Cadpress Express Autodesk moldflow beta Animation reference : Moldex 3d

25 Part Material Process Conclusion
Design Analysis Engineering drawing Part Material study Material selection Material Mold design Heating system analysis Cooling system analysis Process parameters Process Process dependency parameters are identified and analyzed Process data sheet preparation Future work involves manufacture of the mold and part

26 Thank You Questions and discussion

27 Analysis conditions Static Structural analysis Properties Units
Al 6061 T6 Al alloy Carbon epoxy Density lb / in3 0.097 0.0975 0.054 Young’s modulus msi 10 10.297 8.357 Poisson ratio 0.33 0.3 Parts Wheel hub, existing wheel center Wheel rim Proposed wheel center

28 Heating system Uniform temperature distribution  uniform cure
Electric heaters – less expensive, easy installation Temperature gradient 10 deg c Types Cartridge heaters (commonly used) Strip heaters (suitable for surface heating) Coil heaters (custom made to suit application) Wattage required for heating the mold in 30 min – 3.6 KW (heat required without losses = 3.1 KW + heat required for the charge = KW+ heat losses = 0.41 KW) Image ref :

29 Transient Thermal analysis (mold preheat time 30 min)
Analysis conditions Transient Thermal analysis (mold preheat time 30 min) Mold – Al 6061 Heaters – SS 304

30 Analysis conditions Fluid flow simulation Heat transfer
coefficient: 25 W/m2/K External fluid temperature: °C Fluid -Water Solid -Aluminum 6061 Time : 10 min Thermodynamic parameters Static Pressure: lbf/in2 Temperature: °C Solid parameters Default material: Aluminum 6061 Initial solid temperature: °C

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