Capillary Characterization of Fibrous Reinforcement and Optimization of Injection Strategy in Resin Transfer Molding
Abstract
:1. Introduction
2. Capillary Rise Experiments
2.1. Materials and Setup
2.2. Image Processing
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- conversion of colored pictures into gray levels;
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- conversion of gray levels into black and white;
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- edge detection to locate the flow front position.
2.3. Modeling of Capillary Rise
2.4. Optimal Imbibition Velocity
3. Impregnation in RTM Mold of Varying Geometry
3.1. Manufacturing
- Maintaining the optimal impregnation velocity throughout the plate (CSL and DLS tests).
- Maintaining the optimal impregnation velocity only in the small section (CS and DS tests).
- Maintaining the optimal impregnation velocity only in the large section (CL and DL tests).
3.2. Void Content Analysis
4. Conclusions
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- The capillary rise method gives a good approximation of the optimum velocity for practical manufacturing, which is close to the lower bound of the predicted range.
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- The transport of voids during mold filling tends to increase the porosity near the vents. In case of parts of complex geometry, it is recommended to inject in divergent mode in order to minimize the void content near the outlet.
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- It is not necessary to inject at the lowest impregnation velocity of the optimal range throughout the whole part. If overall filling time is a critical issue, the injection speed can be increased at the beginning of the filling without compromising the quality of the final part.
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Bh (mm2·s−1) | Lc (mm) | vopt (mm·s−1) | |
---|---|---|---|
Warp | 32–55 | 1.94 | 16.5–28.4 |
Weft | 45–128 | 3.26 | 13.8–39.3 |
Hexadecane | Vinyl Ester 411–350 | Epoxy DER 383 | |
---|---|---|---|
Viscosity (mPa·s) | 3.51 | 480 | 896 |
Surface tension (mN/m) | 27.5 | 34.3 | 44.8 |
Contact angle (°) | 0 | 44 | 32 |
vopt (mm·s−1) | ||||
---|---|---|---|---|
Vinyl Ester Resin | Epoxy Resin | |||
This Work | Lebel et al. [18] | This Work | Lebel et al. [18] | |
Warp | 0.109–0.186 | 0.077–0.18 | 0.0912–0.153 | 0.06–0.14 |
Weft | 0.0909–0.258 | 0.077–0.20 | 0.0763–0.212 | 0.06–0.14 |
CONVERGENT | DIVERGENT | |||||
---|---|---|---|---|---|---|
Plate Name | Large Section | Small Section | Plate Name | Small Section | Large Section | |
Case 1 | CL | vopt | 2 vopt | DL | 2 vopt | vopt |
Case 2 | CS | 0.5 vopt | vopt | DS | vopt | 0.5 vopt |
Case 3 | CLS | vopt | vopt | DSL | vopt | vopt |
Distance from Injection Point | ||||||||
---|---|---|---|---|---|---|---|---|
3 cm | 8 cm | 12 cm | 22 cm | 27 cm | 31 cm | |||
Void content (%) | Divergent | DL | 0.915 | 1.031 | 1.121 | 1.524 | 1.711 | 2.068 |
DS 1 | 1.499 | 1.300 | 0.990 | 0.956 | 1.053 | 1.437 | ||
DSL | 1.291 | 1.160 | 1.071 | 1.312 | 1.744 | 2.415 | ||
Convergent | CL | 0.582 | 0.397 | 1.855 | 1.753 | 2.952 | 3.377 | |
CS | 0.753 | 0.794 | 0.829 | 1.671 | 2.525 | 2.713 | ||
CLS | 1.163 | 1.536 | 2.552 | 2.324 | 3.024 | 2.786 |
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Causse, P.; Ravey, C.; Trochu, F. Capillary Characterization of Fibrous Reinforcement and Optimization of Injection Strategy in Resin Transfer Molding. J. Compos. Sci. 2018, 2, 19. https://doi.org/10.3390/jcs2020019
Causse P, Ravey C, Trochu F. Capillary Characterization of Fibrous Reinforcement and Optimization of Injection Strategy in Resin Transfer Molding. Journal of Composites Science. 2018; 2(2):19. https://doi.org/10.3390/jcs2020019
Chicago/Turabian StyleCausse, Philippe, Christophe Ravey, and François Trochu. 2018. "Capillary Characterization of Fibrous Reinforcement and Optimization of Injection Strategy in Resin Transfer Molding" Journal of Composites Science 2, no. 2: 19. https://doi.org/10.3390/jcs2020019