Modeling of Natural Fiber- Thermoplastic Composites Manufactured with Molding Processes Laurent Matuana Workshop: Future of Modeling in Composites Molding Processes Co-Sponsored by NSF, DOE and APC June 9-10, 2004

NFPC in North America Wood-fibers (90%) Building industry Extrusion process Agri-fibers (10%) Automotive industry Molding process Natural Fibers-Plastic Composites (NFPCs)

Current State of the Art Raw materials Step 1 Compounding End products Step 2 Manufacturing Step 3 Property testing 100% input control 100% output control Lack of on-line control Bad Feed back Good Feed forward Design

Gaps Limited information on material-process-property relationships for NFPCs, Process models to predict the flow characteristics of the blends, formation of voids, alignment of fibers, and mechanical properties of NFPCs are almost inexistent, Analytical models and computational simulation are not extensively used for NFPCs manufactured with molding processes.

Modeling Issues with Natural Fibers  Non-uniform fibers  Difficult to characterize fiber source  Cross-section may be different between fibers and within a single fiber  Single fibers versus fiber bundles, both may be present  Non-rigid fibers  Long flexible fibers  Rigidity can change with temperature, moisture content  Fiber Attrition  Breakage can depend upon temperature, moisture content

Future Directions  Process control and optimization  On line and non-destructive evaluation (NDE) of the properties of NFPCs  Flow visualization of NFPC blends  Process modeling and simulation by process data  Application of numerical analysis methods

 Develop a methodology for simulating the flow and other physico-mechanical properties of the composites,  Apply the methodology to evaluate the effects material components and processing conditions on the properties of the composites,  Define the range of applicability and the sensitivity to various input parameters for the methodology developed,  Assess the accuracy of the model and assumptions made in the deductions (i.e., sensitivity of empirical design parameters),  Develop design and manufacturing guides. Future Directions (cont’d)

Specific Research Trusts to Fill the Gaps  Integration of two different industries: Forest products industry Plastic industry  Multidisciplinary research for modeling of physical phenomena within natural fibers and plastics during processing and use (e.g., adhesion, void formation, fiber alignment, physico-mechanical and flow properties, etc.), Application of numerical analysis methods to various problems of NFPCs.