Evaluation of the Static Behavior of WPC-GFRP Sandwich Panels: An Experimental, Theoretical, and Numerical Study

Document Type : Original Article

Authors

Faculty of Civil Engineering, Babol Noshirvani University of Technology, Babol, Iran

Abstract

Wood-plastic composite (WPC) is a material composed of wood particles, recycled plastics, and resin, and plays an important role from an economic standpoint. Due to its high compressive and tensile strength, WPC can be used as decking in applications such as pier flooring or small bridge decks. In this study, different glass fiber-reinforced polymer (GFRP) layers were employed to investigate the ultimate load, stiffness, and maximum deformation of WPC-GFRP sandwich panels. Given WPC's lower tensile strength relative to its compressive strength, the reinforcing layers were primarily applied to the bottom face sheets. The loading applied in these experiments was of two types, linear and point loading, perpendicular to the panel surface, to simulate the conditions when such panels are used as flooring. Following the experimental program, theoretical and numerical methods were employed for further analysis of the specimens. In the theoretical approach, beam theory was used because the loading, support conditions, and material behavior closely resembled those of beams. In the numerical approach, uniaxial tests were conducted to determine the material properties and stress–strain relationships, which were then implemented in the finite element model. Overall, the results indicate that the use of a single GFRP layer significantly improves both the strength and stiffness of the panels. However, adding multiple layers does not lead to a considerable improvement in strength, although it slightly enhances stiffness. From an economic perspective, the use of more than one GFRP layer does not appear to be cost-effective. Furthermore, a good agreement was observed among the experimental, theoretical, and numerical results, confirming the reliability of the modeling approaches.

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Main Subjects


  1. Friedrich, D. Thermoplastic moulding of Wood-Polymer Composites (WPC): A review on physical and mechanical behaviour under hot-pressing technique. Composite Structures, 2021; 262: 113649. doi:10.1016/j.compstruct.2021.113649.
  2. Naghipour, M., Arefi, S. L., Nematzadeh, M. Performance of longitudinal grooves to prevent debonding of GFRP sheets used for the reinforcement of WPC beams. European Journal of Environmental and Civil Engineering, 2013; 17: 761-776. doi:10.1080/19648189.2013.815136.
  3. Gardner, D. J., Han, Y., Wang, L. Wood–Plastic Composite Technology. Current Forestry Reports, 2015; 1: 139-150. doi:10.1007/s40725-015-0016-6.
  4. Naghipour, M., Nematzadeh, M., Yahyazadeh, Q. Analytical and experimental study on flexural performance of WPC–FRP beams. Construction and Building Materials, 2011; 25: 829-837. doi:10.1016/j.conbuildmat.2010.06.104.
  5. Wechsler, A., Hiziroglu, S. Some of the properties of wood–plastic composites. Building and Environment, 2007; 42: 2637-2644. doi:10.1016/j.buildenv.2006.06.018.
  6. Chini, M., Arefi Lale, S., Zolfani Hashemkhani, S., Ustinovicius, L. Choosing a proper method for strengthening WPC beams with grooving method using SWARA-EDAS. Archives of Civil Engineering, 2018; 64: 161-174. doi:10.2478/ace-2018-0050.
  7. Li, Y.-F., Tsai, M.-J., Wei, T.-F., Wang, W.-C. A study on wood beams strengthened by FRP composite materials. Construction and Building Materials, 2014; 62: 118-125. doi:10.1016/j.conbuildmat.2014.03.036.
  8. Lale Arefi, S., Naghipour, M., Turskis, Z., Nematzadeh, M. Evaluation of grooving method to postpone debonding of FRP laminates in WPC-FRP beams. Journal of Civil Engineering and Management, 2014; 20: 237-246. doi:10.3846/13923730.2013.878379.
  9. Zolfaghari, A., Behravesh, A. H., Adli, A. Continuous glass fiber reinforced wood plastic composite in extrusion process: Mechanical properties. Materials & Design, 2013; 51: 701-708. doi:10.1016/j.matdes.2013.04.082.
  10. Behravesh, A., Zohdi Aghdam, A., Soury, E. Experimental investigation of injection molding of wood/plastics composites. Journal of reinforced plastics and composites, 2010; 29: 456-465. doi:10.1177/0731684408099406.
  11. Li, Y.-F., Xie, Y.-M., Tsai, M.-J. Enhancement of the flexural performance of retrofitted wood beams using CFRP composite sheets. Construction and Building Materials, 2009; 23: 411-422. doi:10.1016/j.conbuildmat.2007.11.005.
  12. Plevris, N., Triantafillou Thanasis, C. FRP‐Reinforced Wood as Structural Material. Journal of Materials in Civil Engineering, 1992; 4: 300-317. doi:10.1061/(ASCE)0899-1561(1992)4:3(300).
  13. Triantafillou Thanasis, C., Deskovic, N. Prestressed FRP Sheets as External Reinforcement of Wood Members. Journal of Structural Engineering, 1992; 118: 1270-1284. doi:10.1061/(ASCE)0733-9445(1992)118:5(1270).
  14. Naghipour, M., Taheri, F., Zou, G. P. Evaluation of Vibration Damping of Glass-Reinforced-Polymer-Reinforced Glulam Composite Beams. Journal of Structural Engineering, 2005; 131: 1044-1050. doi:10.1061/(ASCE)0733-9445(2005)131:7(1044).
  15. Adhikary, K. B., Pang, S., Staiger, M. P. Dimensional stability and mechanical behaviour of wood–plastic composites based on recycled and virgin high-density polyethylene (HDPE). Composites Part B: Engineering, 2008; 39: 807-815. doi:10.1016/j.compositesb.2007.10.005.
  16. Wang, K., Xu, X., Huo, R., Fang, H., Chen, X. Flexural reinforcement of wood plastic composite panels by bonding glass fiber reinforced polymer sheets and embedding bars. Polymer Composites, 2024; 45: 14595-14607. doi:10.1002/pc.28784.
  17. Wang, K., Yu, C., Liu, W., Huo, R., Fang, H., Chen, X. Study on flexural property of glass fiber-reinforced polymer reinforced wood–plastic composite panels. Wood Material Science & Engineering, 2025; 20: 478-487. doi:10.1080/17480272.2024.2355554.
  18. Jian, B., Mohrmann, S., Li, H., Li, Y., Ashraf, M., Zhou, J., Zheng, X. A Review on Flexural Properties of Wood-Plastic Composites. Polymers, 2022; 14: 3942. doi:10.3390/polym14193942.
  19. Hamed, E., Negru, D., Yalda, R. Structural Performance of Precast Concrete Sandwich Panels Made with FRP Vierendeel Truss–Like Connectors. Journal of Composites for Construction, 2022; 26: 04022027. doi:10.1061/(ASCE)CC.1943-5614.0001215.
  20. Huang, J.-Q., Dai, J.-G. Flexural performance of precast geopolymer concrete sandwich panel enabled by FRP connector. Composite Structures, 2020; 248: 112563. doi:10.1016/j.compstruct.2020.112563.
  21. ASTM International. ASTM D695: Standard test method for compressive properties of rigid plastics. West Conshohocken (PA): 1996. doi:10.1520/D0695-23.
  22. ASTM International. ASTM D638: Standard test method for tensile properties of plastics. West Conshohocken (PA): 2003. doi:10.1520/D0638-14.
Volume 2, Issue 2 - Serial Number 2
February 2026
Pages 1-27
  • Receive Date: 23 September 2025
  • Revise Date: 30 October 2025
  • Accept Date: 01 November 2025
  • First Publish Date: 06 November 2025