Modulus of elasticity in scarf-jointed wooden beams: A case study with polyvinyl acetate and isocyanate adhesives
2014
Roohnia, M. (Islamic Azad University, Karaj (Iran). Karaj Branch, College of Agriculture and Natural Resources, Department of Wood and Paper Science and Technology) | Hemmasi, A. | Yavari, A. | Khademieslam, H. | Bazyar, B.
In the present study, elastic properties of scarf-jointed oak (Quercus castaneifolia) timbers with the application of two different types of adhesives (polyvinyl acetate and isocyanate) were evaluated using free flexural vibration of free-free beam method in different flexural directions of vibration, i.e., tangential and redial directions. Samples were taken from trees of Hyrcanian forests in Iran with nominal dimensions of 20 * 20 * 360 cubic mm. Comparing the results of elastic properties of clear oak wood beams with scarf-jointed samples wood showed that scarf joints with the bonding angles of 70deg and 75deg, covered by polyvinyl acetate adhesive, did not demonstrate any significant effect on modules of elasticity. Scarf-jointed beams with smaller joint angles (60deg and 65deg) were considerably weaker or totally unreliable in their moduli of elasticity. It is also shown that the magnitude of effect gets worst by using isocyanate rather than polyvinyl acetate adhesive.
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