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Basic information about a final thesisAdditional informationAdditional information about the final thesis follows. Click on the language link to display the information in the desired language.
|Language of final thesis:||English|
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|Title of the thesis:||Reinforcement of Wood-based materials|
|Summary:||Wood-based materials can be reinforced in order to homogenize isotropic mechanical properties and decrease variability due to natural defects or simply in order to improve mechanical properties. The type of reinforcement has to be designed according to the final application. This thesis does not focus on some specific product but sets a requirement that final material should withstand a higher load than original wood-based material. Several methods and materials were used to investigate possibilities for plywood, beam, and particleboard. Basalt and carbon fibers were used as a reinforcement. These fibers were woven as plain, twilled and unidirectional fabric. As a matrix, epoxy, polymeric emulsion, polyvinyl acetate, melamine-urea formaldehyde, phenol-resorcinol formaldehyde, and polyurethane resin were tested. Research is divided into articles and each of them deals with a particular problem and uses specific materials. Basalt fabric reinforced epoxy resin was externally mounted on beech plywood and strengthening effect on solely compression and tension side was investigated. Results proved that both sides are important and compression and tension reinforcement increase the modulus of elasticity and bending strength respectively. However, thick reinforcement tent to delaminate from the tension side. Alternatives with thin beech plywood and basalt fiber-reinforced polyvinyl acetate resin did not show delamination but high ductility that could absorb a lot energy caused by the static and dynamic load. Particleboard was used as a base material to test the effect of basalt scrim as well as the effect of scrim position in relation to the panel surface. It was confirmed that scrim significantly improved flexural mechanical properties and the closer to surface scrim was, the higher was an improvement. However, basalt scrim showed low adhesion with melamine-urea formaldehyde that allowed some slippage of yarns. A corrugated shape was developed for timber beams. This shape was flexible in a transverse direction as well as had an enlarged contact area with a beam. Therefore, no delamination due to flexural load and load induced by cyclic moisture was observed. However, flat reinforcement did delaminate in both cases. Finally, all resins were compared for bond strength with basalt fibers and some perspective matrices such as phenol-resorcinol formaldehyde and polyurethane were recommended for wood reinforcement. |
|Key words:||Wood-based materials, Basalt fibers, Carbon fibers, Reinforcement|
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