Home The layer-structure transition of glass-fiber-reinforced composite materials
Article
Licensed
Unlicensed Requires Authentication

The layer-structure transition of glass-fiber-reinforced composite materials

  • Senji Hamanaka , Chisato Nonomura and Atsushi Yokoyama EMAIL logo
Published/Copyright: December 25, 2019
Become an author with De Gruyter Brill
Submit Manuscript Author Information
Journal of Polymer Engineering
From the journal Journal of Polymer Engineering Volume 40 Issue 1

Abstract

This study aims to investigate whether the layer-structure transition governed by fiber orientation is caused by the change in the elongational strain field or by the change in the shear strain field during the filling process in injection molding using short-fiber-reinforced thermoplastic resin. To this end, a polyamide 6 containing 30 wt% of short-fiber glass was compounded, and a simple plate was injection-molded. The fiber orientation of the plate was observed via X-ray computed tomography, and the fiber orientation distribution was quantified as fiber orientation tensors. The transition of the layer structure, which is mainly composed of the shell layer and core layer during the filling process, was evaluated on the basis of the fiber orientation distribution. The experimental results were compared with velocity information obtained via flow analysis of elongational and shear strain fields. The results showed that flow induction affects the layer-structure transition and that the transition occurs because of changes in the elongational strain field and not because of changes in the shear strain field during the filling process. Thus, the elongational strain field is an important consideration when modeling fiber orientation.

Keywords: composite; fiber orientation; injection molding; polyamide 6; X-ray CT

Acknowledgments

We thank T. Wakano and Y. Tanida for assistance with experiments and for useful discussions. This work was supported by the Kyoto Prefecture Textile Machinery and Metals Promotion Center.

Appendix 1

Information of flow analysis model

The governing equations in the Hele-Shaw flow are expressed as follows:

(1)∂p∂x=∂∂z(η∂u∂z), ∂p∂y=∂∂z(η∂v∂z)
(2)∂(u¯)∂x+∂(v¯)∂y=0
(3)ρCp(∂T∂t+u¯∂T∂x+v¯∂T∂y)=k∂2T∂z2+ηγ˙2

Equation (1) is the equation of motion (Navier-Stokes equation), Equation (2) is the continuity equation, and Equation (3) is the energy equation. In these equations, (u, v) is the velocity component in the (x, y) direction, (u¯, v¯)  is the average value in the thickness direction of each flow velocity component, ρ is density, t is time, p is pressure, η is viscosity, Cp is the specific heat capacity, k is thermal conductivity, and γ˙ is the shear rate. Appendix Figure 9A and B show the specific heat and thermal conductivity data used in the analysis. The viscosity equations of the Cross-WLF model are expressed as

Figure 9: (A) The specific heat capacity and (B) the thermal conductivity for numerical analysis.
Figure 9:

(A) The specific heat capacity and (B) the thermal conductivity for numerical analysis.

(4)η=η01+(η0γ˙τ*)1−n
(5)η0=D1exp[−A1(T−T*)A2+(T−T*)]

In Equation (4), η is viscosity, η0 is the zero-shear viscosity, γ˙ is the shear rate, τ* is the critical shear stress level at the transition point to shear thinning flow behavior, and n is the power-law index at high shear rate. In Equation (5), T is the temperature, T* is the glass-transition temperature, A2=A3+D3p, and T*=D2+D3p, p is the pressure. Parameters τ*, n, D1, D2, D3, A1, and A3 are fitting coefficients. The fitting coefficients of Equations (4) and (5) were determined according to the shear viscosity measured by a capillary rheometer. The parameter values are τ*=1.354×105 Pa, n=0.163 (dimensionless), D1=6.414×1010 Pa s, D2=4.002×102 K, D3=0.000 K/Pa, A1=2.700×101 (dimensionless), and A3=5.160×101 K; (Pa) means Pascal, (s) means second, (K) means Kelvin, and (k) means kilo.

References

[1] Bay RS, Tucker CL. Polym. Eng. Sci. 1992, 32, 240–253.10.1002/pen.760320404Search in Google Scholar

[2] Bay RS, Tucker CL. Polym. Compos. 1992, 13, 317–331.10.1002/pc.750130409Search in Google Scholar

[3] Bay RS, Tucker CL. Polym. Compos. 1992, 13, 332–341.10.1002/pc.750130410Search in Google Scholar

[4] Thi TBN, Morioka M, Yokoyama A, Hamanaka S, Yamashita K, Nonomura C. J. Mater. Process. Technol. 2015, 219, 1–9.10.1016/j.jmatprotec.2014.11.048Search in Google Scholar

[5] Hine P, Parveen B, Brands D, Caton-Rose F. Compos. Part A 2014, 64, 70–78.10.1016/j.compositesa.2014.04.017Search in Google Scholar

[6] Gupta M, Wang KK. Polym. Compos. 1993, 14, 367–382.10.1002/pc.750140503Search in Google Scholar

[7] Hamanaka S, Nonomura C, Thi TBN, Yokoyama A. J. Polym. Eng. 2019, 39, 653–660.10.1515/polyeng-2018-0371Search in Google Scholar

[8] Crowson RJ, Folkes MJ, Bright PF. Polym. Eng. Sci. 1980, 20, 925–933.10.1002/pen.760201403Search in Google Scholar

[9] Jeffery GB. Proc. R. Soc. Lond. A 1922, 102, 161–179.10.1098/rspa.1922.0078Search in Google Scholar

[10] Vincent M, Agassant JF. Rheol. Acta. 1985, 24, 603–610.10.1007/BF01332594Search in Google Scholar

[11] Modlen GF. J. Mater. Sci. 1969, 4, 283–289.10.1007/BF00550396Search in Google Scholar

[12] Kleindel S, Salaberger D, Eder R, Schretter H, Hochenauer C. IPP 2015, 30, 366–380.10.3139/217.3047Search in Google Scholar

[13] Bernasconi A, Cosmi F, Dreossi D. Compos. Sci. Technol. 2008, 68, 2574–2581.10.1016/j.compscitech.2008.05.022Search in Google Scholar

[14] Bernasconi A, Cosmi F, Hine PJ. Compos. Sci. Technol. 2012, 72, 2002–2008.10.1016/j.compscitech.2012.08.018Search in Google Scholar

[15] Ayadi A, Nouri H, Guessasma S, Roger F. Compos. Struct. 2016, 136, 635–649.10.1016/j.compstruct.2015.10.041Search in Google Scholar

[16] Mazahir SM, Vélez-García GM, Wapperom P, Baird D. Compos. Part A Appl. Sci. Manuf. 2013, 51, 108–117.10.1016/j.compositesa.2013.04.008Search in Google Scholar

[17] Ko J, Youn JR. Polym. Compos. 1995, 16, 114–124.10.1002/pc.750160203Search in Google Scholar

[18] Vincent M, Giroud T, Clarke A, Eberhardt C. Polymer 2005, 46, 6719–6725.10.1016/j.polymer.2005.05.026Search in Google Scholar

Received: 2019-06-30
Accepted: 2019-10-12
Published Online: 2019-12-25
Published in Print: 2019-12-18

©2020 Walter de Gruyter GmbH, Berlin/Boston

Articles in the same Issue

  1. Frontmatter
  2. Material properties
  3. Characterization and mechanism of accelerated curing of adhesives by in situ ultrasonic vibration for bonded joints
  4. Effects of tension fatigue on the structure and properties of carbon black filled-SBR and SBR/TPI blends
  5. New fire-resistant epoxy thermosets: nonisothermal kinetic study and flammability behavior
  6. Preparation and assembly
  7. The layer-structure transition of glass-fiber-reinforced composite materials
  8. Geraniol and cinnamaldehyde as natural antibacterial additives for poly(lactic acid) and their plasticizing effects
  9. Formation of PA12 fibres via melt electrospinning process: parameter analysis and optimisation
  10. Flexible epoxy composite coatings modified by reactive rubber with improvements in water and corrosive resistances
  11. Nanocrystalline cellulose prepared by double oxidation as reinforcement in polyvinyl alcohol hydrogels
  12. Engineering and processing
  13. Improvement of stability and release of (-)-epicatechin by hot melt extrusion
  14. Thermodynamic analysis and injection molding of hierarchical superhydrophobic polypropylene surfaces
https://doi.org/10.1515/polyeng-2019-0208
Keywords for this article
composite; fiber orientation; injection molding; polyamide 6; X-ray CT

Articles in the same Issue

  1. Frontmatter
  2. Material properties
  3. Characterization and mechanism of accelerated curing of adhesives by in situ ultrasonic vibration for bonded joints
  4. Effects of tension fatigue on the structure and properties of carbon black filled-SBR and SBR/TPI blends
  5. New fire-resistant epoxy thermosets: nonisothermal kinetic study and flammability behavior
  6. Preparation and assembly
  7. The layer-structure transition of glass-fiber-reinforced composite materials
  8. Geraniol and cinnamaldehyde as natural antibacterial additives for poly(lactic acid) and their plasticizing effects
  9. Formation of PA12 fibres via melt electrospinning process: parameter analysis and optimisation
  10. Flexible epoxy composite coatings modified by reactive rubber with improvements in water and corrosive resistances
  11. Nanocrystalline cellulose prepared by double oxidation as reinforcement in polyvinyl alcohol hydrogels
  12. Engineering and processing
  13. Improvement of stability and release of (-)-epicatechin by hot melt extrusion
  14. Thermodynamic analysis and injection molding of hierarchical superhydrophobic polypropylene surfaces
Sign up now to receive a 20% welcome discount
Institutional Access
How does access work?
Have an idea on how to improve our website?
Please write us.
© 2025 De Gruyter Brill
Downloaded on 26.9.2025 from https://www.degruyterbrill.com/document/doi/10.1515/polyeng-2019-0208/html
Scroll to top button