Feed-forward adaptive control of resin transfer molding (RTM) processes is crucial for producing a high yield of usable parts for industrial applications. The enabling technique for this process is non-invasive monitoring of the fill-front position and the degree of cure of the resin as it is injected into the mold. Successful implementation of a sensing system capable of meeting these criteria will result in a high yield of composite parts that can be used for the next generation of aircraft. This article articulates the possibility of a hybrid sensing system for multiparameter monitoring during RTM processes. It addresses the fundamental engineering trade-offs between penetration depth and signal strength, discussing how to account for fringing electric field (FEF) effects present in the system. FEF effects hinder the measurement accuracy of the sensor system. This article describes how these effects are addressed using a mapping algorithm that is developed using numerical simulations of the experimental setup. The experimental setup utilizes a rectangular RTM tool and a water-glycerin mixture which simulates mechanical properties of epoxy resins, prior to cure. Modeling of the FEF effects helps to achieve high measurement accuracy of the fill front location.
Han, K. and Lee, L.J. (1996). Dry Spot Formation and Changes in Liquid Composites Molding: I-Experiments , Journal of Composite Materials, 30: 1458-1474 .
2.
Han, K. , Lee, L.J. and Nakamura, S. (1996). Dry Spot Formation and Changes in Liquid Composites Molding: II-Modeling and Simulation , Journal of Composite Materials, 30: 1475-1493 .
3.
Mogavero, J. , Sun, J.Q. and Advani, S.G. (June 1997). A Nonlinear Control Method for Resin Transfer Molding , Polymer Composites, 18(3): 412-417 .
4.
Yoon, M.K. and Sun, J.Q. (Jan. 2002). Adaptive Control of Flow Progression in Resin Transfer Molding , Journal of Materials Processing & Manufacturing Science, 10(3): 171-182 .
5.
Shepard, D.D. (Nov. 1998). Resin Flow Front Monitoring Saves Money and Improves Quality , SAMPE Journal, 34(6): 31-35 .
6.
Berker, B. , Barooah, P. and Sun, J.Q. (Oct. 1997). Sequential Logic Control of Liquid Injection Molding with Automatic Vents and Vent-to-Gate Converters , Journal of Materials Processing & Manufacturing Science, 6(2): 81-103 .
7.
Demirci, H.H. and Coulter, J.P. (Feb. 1996). A Comparative Study of Nonlinear Optimization and Taguchi Methods Applied to the Intelligent Control of Manufacturing Processes , Journal of Intelligent Manufacturing, 7(1): 23-38 .
8.
Parthasarathy, S. , Mantell, S.C. , Stelson, K.A. , Bickerton, S. and Advani, S.G. (1998). Real-Time Sensing and Control of Resin Flow in Liquid Injection Molding Processes , In: Proceedings of the 1998 American Control Conference, Vol. 4, pp. 2181-2184 .
9.
Ahn, S.H. , Lee, W.I. and Springer, G.S. (1995). Measurement of the 3-Dimensional Permeability of Fiber Preforms using Embedded Fiber Optic Sensors , Journal of Composite Materials, 29(6): 714-733 .
10.
Bernstein, J.R. and Wagner, J.W. (May 1997). Fiber Optic Sensors for use in Monitoring Flow Front in Vacuum Resin Transfer Molding Processes , Review of Scientific Instruments, 68(5): 2156-2157 .
11.
Crosby, P.A. , Powell, G.R. , Fernando, G.F. , Waters, D.N. , France, C.M. and Spooncer, R.C. (1997). A Comparative Study of Optical Fibre Cure Monitoring Methods, In: SPIE, pp. 141-153.
12.
Shepard, D.D. and Smith, K.R. (1999). Ultrasonic Cure Monitoring of Advanced Composites , Sensor Review, 19(3): 187-191 .
13.
Fomitchov, P.A. , Kim, Y.K. , Kromine, A.K. and Krishnaswamy, S. (2002). Laser Ultrasonic Array System for Real-Time Cure Monitoring of Polymer-Matrix Composites , Journal of Composite Materials, 36(15): 1889-1901 .
14.
Woerdeman, D.L. and Parnas, R.S. (Oct. 1995). Cure Monitoring in RTM using Fluorescence , Plastics Engineering, 51(10): 25 -&.
15.
Tavakoli, S.M. , Avella, M. and Phillips, M.G. (1990). Fiber Resin Compatibility in Glass Phenolic Laminating Systems , Composites Science and Technology, 39(2): 127-145 .
16.
Barooah, P. , Berker, B. and Sun, J.Q. (Jan. 1998). Lineal Sensors for Liquid Injection Molding of Advanced Composite Materials , Journal of Materials Processing & Manufacturing Science, 6(3): 169-184 .
17.
Lee, C.W. , Rice, B.P. , Buczek, M. and Mason, D. (Nov. 1998). Resin Transfer Process Monitoring and Control , SAMPE Journal, 34(6): 48-55 .
18.
Schwab, S.D. , Levy, R.L. and Glover, G.G. (Apr. 1996). Sensor System for Monitoring Impregnation and Cure During Resin Transfer Molding , Polymer Composites, 17(2): 312-316 .
19.
Alig, I. , Jenninger, W. , Junker, M. and deGraaf, L.A. (1996). Dielectric Relaxation Spectroscopy During Isothermal Curing of Semi-Interpenetrating Polymer Networks , Journal of Macromolecular Science-Physics, B35(3-4): 563-577 .
20.
Potapov, A.A. (Sept. 1993). Temperature-Dielectric Spectroscopy of Solutions , Instruments and Experimental Techniques, 36(5): 772-776 .
21.
Kranbuehl, D. , Hood, D. , Kriss, A. , Barksdale, R. , Loos, A.C. , Macrae, J.D. and Hasko, G. (Mar. 1996). In situ FDEMS Sensing and Modeling of Epoxy Infiltration, Viscosity and Degree of Cure During Resin Transfer Molding of a Textile Preform , Abstracts of Papers of the American Chemical Society, 211: 17-MSE .
22.
Kranbuehl, D. , Hoff, M. , Eichinger, D. , Clark, R. and Loos, A. (1989). Monitoring and Modeling the Cure Processing Properties of Resin Transfer Molding Resins , International SAMPE Symposium and Exhibition, 34: 416-425 .
23.
Kranbuehl, D.E. , Kingsley, P. , Hart, S. , Hasko, G. , Dexter, B. and Loos, A.C. (Aug. 1994). In-Situ Sensor Monitoring and Intelligent Control of the Resin Transfer Molding Process , Polymer Composites, 15(4): 299-305 .
24.
Kranbuehl, D. , Delos, S. , Hoff, M. , Weller, L. , Haverty, P. and Seeley, J. (1988). Frequency-Dependent Dielectric Analysis - Monitoring the Chemistry and Rheology of Thermosets During Cure, ACS Symposium Series, 367: 100-112.
25.
Rooney, M. , Biermann, P.J. , Carkhuff, B.G. , Shires, D.R. and Mohan, R.V. (1998). Development of In-Process RTM Sensors for Thick Composite Sections , In: Proceedings of the 1998 American Control Conference, Vol. 6, pp. 3875-3878 .
26.
Skordos, A.A. , Karkanas, P.I. and Partridge, I.K. (Jan. 2000). A Dielectric Sensor for Measuring Flow in Resin Transfer Moulding , Measurement Science & Technology, 11(1): 25-31 .
27.
von Hippel, A. (1995). Dielectric Materials and Applications, Artech House, Boston, MA .
28.
Matis, I.G. (1966). Method and Equipment for Determining the Dielectric Constant of Polymer Materials with One-sided Access , Polymer Mechanics, 2(4): 380-383 .
29.
Senturia, S.D. , Sheppard, N.F. , Poh, S.Y. and Appelman, H.R. (Feb. 1981). The Feasibility of Electrical Monitoring of Resin Cure with the Charge-Flow Transistor , Polymer Engineering and Science, 21(2): 113-118 .
30.
Senturia, S.D. , Sheppard Jr., N.F. , Lee, H.L. and Day, D.R. (1982). In-Situ Measurement of the Properties of Curing Systems With Microdielectrometry , Journal of Adhesion, 15(69): 69-90 .
31.
Senturia, S.D. and Garverick, S.L. (Dec. 1983). Method and Apparatus for Microdielectrometry, US Patent No.4,423,371.
32.
Zaretsky, M.C. , Mouayad, L. and Melcher, J.R. (Dec. 1988). Continuum Properties from Interdigital Electrode Dielectrometry , IEEE Transactions on Electrical Insulation, 23(6): 897-917 .
33.
Washabaugh, A. , Schlicker, D.E. , Mamishev, A.V. , Zahn, M. and Goldfine, N. (1999). Dielectric Sensor Arrays for Monitoring of Aging in Composites and Other Low-Conductivity Media , In: SPIE Conference.
34.
Mijovic, J. and Sy, J.W. (Dec. 2000). Dipole Dynamics and Macroscopic Alignment in Molecular and Polymeric Liquid Crystals by Broad-Band Dielectric Relaxation Spectroscopy , Macromolecules, 33(26): 9620-9629 .
35.
Kranbuehl, D.E. , Delos, S.E. and Yi, E. (1985). Measurement and Application of Dielectric Properties , SPIE Technical Papers, 31(311): 73-90 .
36.
Mamishev, A.V. , Du, Y. , Lesieutre, B.C. and Zahn, M. (Apr. 1999). Development and Applications of Fringing Electric Field Dielectrometry Sensors and Parameter Estimation Algorithms , Journal of Electrostatics, 46(2-3): 109-123 .
37.
Goldfine, N.J. (Mar. 1993). Magnetometers for Improved Materials Characterization in Aerospace Applications , Materials Evaluation, 51(3): 396-405 .
38.
Mamishev, A.V. , Lesieutre, B.C. and Zahn, M. (1998). Optimization of Multi-Wavelength Interdigital Dielectrometry Instrumentation and Algorithms , IEEE Transactions on Dielectrics and Electrical Insulation, pp. 408-420 .
39.
Ebersold, C.B. (2000). Racetracking and Porous Medium Displacement in Resin Transfer Molding, Department of Mechanical Engineering, University of Washington .
