1. Collaborative Research: Enhancing the Understanding of the Fundamental Mechanisms of Thermostamping Woven Composites to Develop a Comprehensive Design Tool James Sherwood Jennifer Gorczyca University of Massachusetts Lowell Collaborators: Northwestern University NSF/DOE/APC Workshop: Future of Modeling in Composites Molding Processes (Design & Optimization Session) 9-10June 2004 Arlington, Virginia NSF Grant Number: DMI- 0331267

2. Motivation • Mass production of lightweight low-cost woven-fabric reinforced composite parts • Desirable in automobiles for: • High strength-to-weight ratio (compared to metal counterparts) • Reduce weight  Increase fuel efficiency • Development of predictive design tool

3. Motivation – Thermostamping Punch Binder Ring Fabric Die

4. Motivation – Part Quality [Wilks, 1999]

5. Our Research: • Development of a friction model to capture the behavior of balanced plain-weave composite materials during thermoforming • Incorporation of the friction model into the commercial finite element code ABAQUS • Parametric study of the effect of processing parameters on the reaction force on the punch • Use of the fabric friction model with a fabric constitutive model in a commercial finite element code such as ABAQUS to create a predictive tool

6. ACMTRL Our Research:

7. Our Research: H Hersey Number h  use Power Law viscosity model U fabric velocity W normal force

8. State of the Art – Testing Standards • Study of metal/fabric interface relatively new • ASTM standards exist to determine friction coefficients of sheets • Account for normal load and pull-out velocity • Do not account for sheet viscosity and fiber orientation • Researchers have developed their own test methods (many based on ASTM Standard D 1894)

9. ACMTRL State of the Art – Friction Testing Table from: Gorczyca, Sherwood and Chen (2004). Modeling of Friction and Shear in Thermostamping of Composites – Part I. Journal of Composite Materials. In Press.

10. ACMTRL State of the Art – FEM • Boisse et al. (1996, 2001a, 2001b) • Constitutive model with FEM focuses on formability • Based on Kawabata et al. (1973) • Xue et al. (2003) and Peng (2003) • Focus on constitutive model and incorporation into FEM • Use of shell elements and nonorthogonality Details can be found in: Gorczyca (2004). A study of the frictional behavior of a plain-weave fabric during the thermostamping process. Doctoral dissertation. Mechanical Engineering Dept. UML

11. ACMTRL State of the Art – FEM • Cherouat and Billoët (2001) • Truss elements – tows • Membrane elements – resin • Sidhu et al. (2001) • Truss elements – tows • Shell elements – inter-tow friction and fiber angle jamming • Li et al. (2004) [@ UML] • Truss elements – tows • Shell elements – increasing tangent shear modulus Fabric unit cell Truss Elements Shell Element Details can be found in: Gorczyca (2004). A study of the frictional behavior of a plain-weave fabric during the thermostamping process. Doctoral dissertation. Mechanical Engineering Dept. UML

12. State of the Art – FEM • Reaction force comparison between fabric friction model and Coulomb friction model • Fabric friction model, m=f(H) • Coulomb friction model, m=0.3 Details can be found in: Gorczyca (2004). A study of the frictional behavior of a plain-weave fabric during the thermostamping process. Doctoral dissertation. Mechanical Engineering Dept. UML

13. Vision • Ability to compare results from different testing methods is important (i.e. shear frame and bias extension, and friction) • Researchers must combine finite element modeling and testing efforts to create a robust Design Tool for thermoforming of woven-fabric composite materials • Analytical Design Tool will account for changing: • Constitutive properties • Temperature • Friction properties • Material types and weaves

14. Vision • Continue to collaborate with industry to: • Ensure that the appropriate materials and processing techniques are being investigated • Aid technology transfer from academia to industry

15. Perceived Gaps • Researchers have determined modeling techniques for specific materials, weave types and cases • These methods need to be extended to include “generic” materials, weave types and cases

16. Perceived Gaps • Researchers have developed their own testing methods (true for constitutive property research and friction modeling) • Work with ASTM for standardized test protocols • Analytical methods for comparing test data using different test procedures must be proposed, publicized and peer-reviewed

17. Research Thrusts • Collaborative research among modeling laboratories: • Comparison and interpretation of differences in results among different modeling techniques • Joining of different fabric models, such as friction and constitutive, in model of forming processes and interpretation and publication of results • Use these methods to lead to models for “generic” materials, weaves and cases

18. Research Thrusts • Collaborative research among testing laboratories: • Comparison and interpretation of differences in results using different test procedures • Use these comparisons to work towards standardization of tests and to determine strengths and weaknesses of the different tests that are available

19. Collaborative Research: Enhancing the Understanding of the Fundamental Mechanisms of Thermostamping Woven Composites to Develop a Comprehensive Design Tool James Sherwood Jennifer Gorczyca University of Massachusetts Lowell Collaborators: Northwestern University NSF/DOE/APC Workshop: Future of Modeling in Composites Molding Processes (Design & Optimization Session) 9-10June 2004 Arlington, Virginia NSF Grant Number: DMI- 0331267