Flexural Behavior of Glass Fiber Reinforced Hardboard


  • Stephen J. Smulski
  • Geza Ifju


Hardboard, reinforced wood composite, wood fiber, glass fiber, mechanical properties


The flexural stiffness and strength of a dry-process hardboard matrix were significantly improved by internal reinforcement with continuous glass fibers. The dynamic and static moduli of elasticity and the modulus of rupture of glass fiber reinforced hardboard increased with increasing reinforcement volume fraction. When modelled as a sandwich construction, the static flexural modulus of elasticity of the composite could be accurately predicted from the modulus of elasticity of the wood fiber matrix, and the tensile modulus of elasticity and volume fraction of the glass fiber reinforcement. Excellent linear correlation among the dynamic modulus of elasticity, the static modulus of elasticity, and the modulus of rupture allowed for estimation of the composite failure stress from flexural properties that were determined nondestructively. The results of this study will assist in the design of glass fiber reinforced hardboard composites.


American Plywood Association. 1972. Plywood overlaid with fiberglass-reinforced plastic. Basic Panel Properties. APA Laboratory Report 119, Part 1. American Plywood Assn., Tacoma, WA.nAmerican Society for Testing and Materials. 1981. Standard methods of evaluating the properties of wood-base fiber and particle panel materials. ASTM D 1037-78. ASTM, Philadelphia, PA.nAveston, T., G. Cooper, and A. Kelly. 1972. Single and multiple fracture. In The properties of fiber composites. IPC Science and Technology Press Ltd., Guildford, England.nBiblis, E. 1965. Analysis of wood-fiberglass composite beams within and beyond the elastic region. Forest Prod. J. 15(2):81-88.nBoehme, C., and U. Schulz. 1974. The constructive behavior of GFK-wood sandwiches. Holz Roh- Werkst. 32(7):250-256.nBoehme, C. 1976a. The constructive behavior of GFK-wood sandwiches-Comparison of experimental results with various computation methods. Holz Roh- Werkst. 34(5):155-161.nBoehme, C. 1976b. Improvement in creep behavior of wood based materials by glass fiber reinforced plastic coating. Holz Roh- Werkst. 34(12):453-458.nBulleit, W. 1981. Models for fiberglass reinforced particleboard in flexure. Pages 289-308 in T. Maloney, ed. Proceedings 15th International Particleboard Symposium, Washington State Univ., Pullman, WA.nCavlin, S., and E. Back. 1968. The effect of sheet density and glass fiber addition on the dimensional stability of fiber building boards. Svensk Papperstidning 71(24):883-889.nChan, W. 1979. Strength properties and structural use of tempered hardboard. J. Inst. Wood Sci. 8(4):147-160.nJayne, B. 1959. Vibrational properties of wood. Forest Prod. J. 9(11):413-416.nKuenzi, E. 1959. Structural sandwich design criteria. FPL Report No. 2161. Forest Products Laboratory, Madison, WI.nLundgren, S. 1969. Wood-based sheet as a structural material. Part I. Swedish Wallboard Manufacturers Association, Stockholm, Sweden.nMcNatt, J. 1970. Design stresses for hardboard-Effect of rate, duration and repeated loading. Forest Prod. J. 20(1):53-60.nMcNatt, J. 1975. Effect of rate of loading and duration of load on properties of particleboard. USDA Forest Service Research Paper FPL 270. Forest Products Laboratory, Madison, WI.nMcNatt, J. 1980. Hardboard-webbed beams: Research and application. Forest Prod. J. 30(10):57-64.nMoslemi, A. 1967. Dynamic viscoelasticity in hardboard. Forest Prod. J. 17(1):25-33.nNishikawa, K., A. Matsumoto, and O. Niiro. 1974. Studies on the manufacture of fiberboards mixed with mineral fibers-The effect of mixing ratio of glass chopped strand and kinds of phenolic resin. J. Hokkaido Forest Prod. Res. Inst. 10:11-15.nNishikawa, K., A. Matsumoto, and O. Niiro. 1975. Studies on the manufacture of fiberboards mixed with mineral fibers-The effects of kinds of glass and other mineral fibers. J. Hokkaido Forest Prod. Res. Inst. 1:8-12.nRead, B., and G. Dean. 1978. The determination of dynamic properties of polymers and composites. Adam Hilger Ltd., Bristol, England.nRowlands, R., R. Van Deweghe, T. Laufenberg, and G. Krueger. 1986. Fiber-reinforced wood composites. Wood Fiber Sci. 18(1):39-57.nSaucier, J., and J. Holman. 1975. Structural particleboard reinforced with glass fiber-Progress in its development. Forest Prod. J. 25(9):67-72.nSpaun, F. 1981. Reinforcement of wood with fiberglass. Forest Prod. J. 31(4):26-35.nSteinmetz, P. 1977. Resin systems and glass reinforcements to improve dry-formed hardboards. USDA Forest Service Research Paper FPL 284. Forest Products Laboratory, Madison, WI.nTheakston, F. 1965. A feasibility study for strengthening timber beams with fiberglass. Canadian Agricultural Engineering, January 1965.nTimoshenko, S., and J. Gere. 1972. Mechanics of materials. D. Van Nostrand Co., New York, NY. 552 pp.nWangaard, F. 1964. Elastic deflection of wood-fiberglass composite beams. Forest Prod. J. 14(6):256-260.n






Research Contributions