Visualization of resin impregnation through opaque reinforcement textiles during the vacuum-assisted resin transfer molding process using ultrasound

Abstract

In this study, an ultrasound visualization system has been set up for in-situ monitoring of the resin flow impregnating through opaque carbon fiber reinforcements during the vacuum-assisted resin transfer molding. The flow front advancement through the carbon fabrics covered by a bagging film can be identified and visualized by the high frequency B (brightness) mode ultrasound imaging technique. The resin advancement in the opaque carbon fabrics has turned out to form a non-uniform plug flow along the pressure gradient direction and the potential void formation can be observed from the mesoscopic resin flow behavior: the inter-tow regions have been preferentially filled by the resin fluid and the fiber tow region behaves as a sink that probably remain as a void defect. The local unsaturated transient velocity of the resin flow has been also evaluated, which is particularly important in understanding saturation behaviors in dual-scale fabrics and is hardly measurable by other means. In spite of the hardware limitations on the resolution, the proposed ultrasound visualization system can provide a less expensive and portable visualization tool to understand the microstructure of opaque reinforcements and monitor the resin flow behavior during the vacuum-assisted resin transfer molding process in the industrial composite manufacturing environment.

Keywords

Ultrasound visualization vacuum-assisted resin transfer molding process monitoring carbon fibers

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References

Advani

Sozer

. Process modeling in composites manufacturing, 2nd ed. Boca Raton: CRC Press, pp. 1–43.

Varna

Joffe

Berglund

. Effect of voids on failure mechanisms in RTM laminates. Compos Sci Technol 1995; 53(2): 241–249.

Kuentzer

Simacek

Advani

. Permeability characterization of dual scale fibrous porous media. Compos Part A 2006; 37(11): 2057–2068.

Liu

Parnas

Giffard

. New set-up for in-plane permeability measurement. Compos Part A-Appl Sci Manuf 2007; 38(3): 954–962.

Hoes

Dinescu

Sol

. New set-up for measurement of permeability properties of fibrous reinforcements for RTM. Compos Part A-Appl Sci Manuf 2002; 33(7): 959–969.

Lawrence

Barr

Karmakar

. Characterization of preform permeability in the presence of race tracking. Compos Part A-Appl Sci Manuf 2004; 35(12): 1393–1405.

Nedanov

Advani

. A method to determine 3D permeability of fibrous reinforcement. J Compos Mater 2002; 36(2): 241–254.

Ahn

Lee

Springer

. Measurement of the three-dimensional permeability of fiber preforms using embedded fiber optic sensors. J Compos Mater 1995; 29(6): 714–733.

Dunkers

Lenhart

Kueh

. Fiber optic flow and cure sensing for liquid composite molding. Optics Lasers Eng 2001; 35(2): 91–104.

10.

Antonucci

Giordano

Nicolais

. Resin flow monitoring in resin film in fusion process. J Mater Process Technol 2003; 143–144: 687–692.

11.

Gupta

Sundaram

. Fiber optic sensors for monitoring flow in vacuum enhanced resin infusion technology (VERITy) process. Compos Part A-Appl Sci Manuf 2009; 40(8): 1065–1070.

12.

Scott

Scala

. A review of non-destructive testing of composite materials. NDT Int 1982; 15(2): 75–86.

13.

Mallick

. Fiber-reinforced composites: materials, manufacturing, and design, 3rd ed. Boca Raton: CRC Press, pp. 427–442.

14.

Mckie ADW, Liao TLT and Ryang HS. In situ process monitoring using laser-based ultrasound. In: IEEE 1992 Ultrasonics Symposium: proceedings, Tucson, Arizona.

15.

Stöven

Weyrauch

Mitschang

. Continuous monitoring of three-dimensional resin flow through a fibre perform. Compos Part A-Appl Sci Manuf 2003; 34(6): 475–480.

16.

Cheng

Ono

Jen

. Real-time diagnosis of co-injection molding using ultrasound. Polymer Eng Sci 2007; 47(9): 1491–1500.

17.

Centea

Hubert

. Measuring the impregnation of an out-of-autoclave prepreg by micro-CT. Compos Sci Technol 2011; 71(5): 593–599.

18.

Neacsu

Leisen

Beckham

. Use of magnetic resonance imaging to visualize impregnation across aligned cylinders due to capillary forces. Exp Fluids 2007; 42(3): 425–440.

19.

Endruweit

Glover

Head

. Mapping of the fluid distribution in impregnated reinforcement textiles using magnetic resonance imaging: application and discussion. Compos Part A-Appl Sci Manuf 2011; 42(10): 1369–1379.

20.

Frazier

O'Brien

Jr . Synthetic aperture techniques with a virtual source element. IEEE Trans Ultrason Ferroelectr Freq Control 1998; 45(1): 196–207.

21.

Liu

Hwang

. Transient filling simulations in unidirectional fibrous porous media. Korea-Australia Rheol J 2009; 21(1): 71–79.

22.

Rohatgi

Patel

Lee

. Experimental investigation of flow-induced microvoids during impregnation of unidirectional stitched. Polymer Compos 1996; 17(2): 161–170.

23.

Park

Lee

. Modeling void formation and unsaturated flow in liquid composite molding processes: a survey and review. J Reinf Plast Compos 2011; 30(11): 957–977.