1. Characterization of Raw Material Properties for Optimum LCM Processing Chuck Zhang Florida Advanced Center for Composite Technologies (FAC 2 T) Florida A&M University-Florida State University for NSF/DOE/APC Future of Modeling in Composites Molding Processes June 9, 2004

2. Common Defects in Liquid Composite Molded Parts Dry spots Dimension variations Voids and poor wetting Variations exist in these defects due to the variations in raw materials and processing parameters!

3. Modeling and Simulation Can Help Predict Flow and Dimension Problems Flow-induced dryspot Spring-in by residual stress Effective process modeling and simulation requires accurate raw material properties!

4. Research Issues Statistical characterization of raw materials properties Stochastic modeling and analysis of process and defects Robust design to improve process reproducibility

5. Research Challenges Accurate estimation of permeability for complex part geometry (modeling) In-situ measurement of permeability (experimental) Statistical permeability characterization (modeling & experimental)

6. Gas-assisted, Real-time ASsessment of Permeability (GRASP)

7. Whole-Field Permeability Estimation with GRASP Finite element analysis Fiber preform High permeability Low permeability Estimated permeability Measured pressure Computed pressure Flow validation

8. Close Loop LCM Operation with Hardware-In-The-Loop Simulation Preform and mold N 2 In-situ, whole- field permeability measurement (GRASP) Flow simulation LCM process Process optimization Hardware-in-the-loop GA NN

9. Statistical Characterization of Fiber Permeability with GRASP Woven Carbon Fabrics Standard Dev. = 23.6% of Mean Pressure Distribution Estimated Permeability GRASP may be used to validate permeability estimation model

10. Statistical Characterization of Permeability........ Racetracking permeability........ SimulationExperiment Kg 1, Kr 1 Kg 2, Kr 2 Kg n, Kr n

11. Summary Variations exist in LCM raw materials and processing parameters and LCM process performance varies due to the variations Accurate estimation and statistical characterization of permeability are important to improve LCM part quality and process reproducibility