Withdrawal Strength of Dowels in Plywood and Oriented Strand Board

Plywood and oriented strand board (OSB) are being used increasingly in the construction of upholstered furniture frames. Yet there is little information available concerning the holding strength of various fasteners, and, in particular, dowels in these materials. A study was conducted accordingly, to obtain basic information about the holding strength of dowels in both plywood and oriented strand board. Results of the tests were incorporated into predictive expressions that allow designers to estimate withdrawal strength as a function of the diameter of the dowels, their depth of embedment and the density of the composite material. Given the variability of the composite materials, significant differences between predicted and observed values must be expected. The maximum differences observed in the tests amounted to no more than 44 percent, however, so that the expressions developed nonetheless provide reasonable first estimates of dowel withdrawal strength. Coefficients of determinations for the expressions varied from 0.868 to 0.623. The results indicated that the generous use of adhesives tends to compensate for inherent material problems such as delamination. Ozet: OSB (Oriented Strand Board) ve kontrplak›n doflemeli mobilya iskeletlerinin konstruksiyonunda kullan›m› gun gectikce artmaktad›r. Ancak, bu tur kompozit malzemelerin deiflik balant› elemanlar› ve ozellikle kavela ile tutma mukavemeti hakk›nda yeterli veri yoktur. Bu cal›flmada kavelan›n kontrplak ve OSB ile tutma mukavemeti hakk›nda gerekli temel veriler salanmaya cal›fl›lm›flt›r. Test sonuclar› say›sal formuller haline getirilerek urun tasar›mc›lar›n›n kavela tutma mukavemetini kavela cap›, derinlii ve kompozitin younluunun fonksiyonu olarak tahmin etmeleri amaclanm›flt›r. Kompozit malzemedeki degiskenlik gozonune al›nd›¤›nda, test sonuclar› ile istatistiksel tahminlerden elde edilen sonuclar aras›nda buyuk bir fark olmasi beklenir. Buna karfl›n, test deeri ile istatistiksel tahmin aras›ndaki en buyuk fark›n % 44 olmas›, elde edilen formullerin kavela mukavemetini makul bir duzeyde tahmin ettiini gostermektedir. Formullerin determinasyon katsay›lar› .868 ile .623 aras›nda seyretmifltir. Ayr›ca, test sonuclar› fazla miktarda tutkal kullan›m›n›n delaminasyon gibi kompozite iliflkin baz› problemlerin ortadan kald›r›lmas›na yard›mc› olduunu