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Simuliranje naprezanja u kutnim spojevima drvenih konstrukcija primjenom metode konačnih elemenata Received -prispjelo: 15. 1. 2015. Accepted -prihvaćeno: 5. 5. 2016 630*824.132 doi:10.5552/drind.2016 cay, insect mushroom damages) were considered according to TS 2470 (TS 2470(TS , 1976. Original scientifi c paper • Izvorni znanstveni radPVAc D3 adhesive was provided from Polisan, a producer company in Izmit, Turkey. PVAc D3 is an odorless and non-fl ammable adhesive manufactured according to BS EN204 (BS EN204, 2001) (D3) and DIN 68602 (DIN 68602, 1979) standards. The density of the PVAc D3 adhesive is 1.1 g/m 3 . Based on TS 3891 (TS 3891, 1983), approximately 200 g/m 2 of the adhesive were applied to all surfaces of the mortisetenon and dowel joints. Dowels produced from beech wood (10 mm in diameter x 57 mm long) were used in samples following the standard TS 4539 (TS 4539, 1985). To ensure the strength of the holes in the wood, a 35-mm-deep hole with a diameter of 10 mm was drilled in element "A" using Computer Numerical Control drill machine, while a 25-mm-deep hole was drilled in element "B". FEM analyses were also carried out by using the same values. Mortise dimensions (width x length x depth 14 x 28 x 32,15 mm) were chosen in samples according to the standard TS 4905 (TS 4905, 1986). Holes of "tenon and mortise joints" were fi rst drilled in element B to form the mortise and then element A was prepared for the tenon. Finally, A and B elements were fi t to each other. Glue line was 0.15 mm in thickness for the joint section of all construction parts (dowel and mortise -tenon)The strain gauges used in the experiments were provided from the manufacturer HBM and had a standard range of 120 Ω ± 0.35 %. The strain gauge version was 20/120LY41. The size of the strain gauges was 32 x 3.2 mm. During the experiment, the deformation values gathered from testbox-1001 were saved and tension values were obtained. Preparation of samples 2.2. Priprema uzorakaAs experimental schedule showed in Table 1, a total of 80 experimental samples were used for these studies; two species of wood (Beech and Scotch pine), two joint types (dowel and mortise-tenon), two test methods (diagonal compression and tension), and ten repetitions. A total of 80 samples were conditioned in a room with the temperature of 20 ºC and a relative humidity of 65 % until they reached 12 % equilibrium moisture content. Each L-type corner joint test sample consisted of two elements: "A" with dimensions of 158x42x42 mm and "B" with dimensions 200x42x42 of mm.During the experiment, a strain gauge was bonded 10 mm far from the joint section of the elements for each sample (the inner edge) and the deformation values were measured by 20/120LY41 strain gauges. The same conditions as in the experiments were applied for computer modeling.Istraživanjem je također utvrđeno da se čvrstoća kutnih spojeva može dobro predvidjeti FEM računalnim modeliranjem umjesto provedbom eksperimenata koji zahtijevaju više vremena, povećane troškove i uništavanje većih količina...

Wood dowels are commonly used in the construction furniture, but little information is available about the additive effects of dowels on the ultimate withdrawal strength of single or multidowel joints. This study was carried out to determine the tensile strength of 10-mm-diameter dowels produced from medium-density fiberboard (MDF), plywood, scotch pine (Pinus sylvestris L.), and beech (Fagus orientalis lipsky), bonded parallel and vertical to the surface of MDF and particleboard (Pb) with poly(vinyl acetate) (PVAc) and Desmodur-VTKA (D-VTKA). Tensile strength was applied to the dowels according to the procedure in the ASTM-D 1037 standard. The effects of dowel species, direction of tensile, composite material, and type of adhesive on tensile strength were determined. The results showed that the highest tensile strength was obtained in beech dowels bonded vertically with PVAc adhesive to the surface of MDF at 7.91 N/mm 2 . If the dowels used in furniture production are subjected to great tensile strength, beech dowels bonded with PVAc adhesive on MDF should be used. However, when dowels produced from MDF and plywood waste are used, they also can produce positive results.

Laminated veneer lumbers (LVLs) manufactured from wood with different adhesives are being increasingly used in the construction of furniture frames and buildings. Yet there is little information available concerning the dimensional stability and shear strength of LVLs after being exposed to steam. In this study, LVLs were manufactured from poplar and beech veneers with phenol/formaldehyde (PF), poly(vinyl acetate) (PVAc), Desmodur-VTKA (D-VTKA) and urea/formaldehyde (UF) adhesives. Dimensional stability of LVLs was measured after being exposed to steam for 2, 6, 12, 24, 48 and 96 h, according to the Turkish Standard (TS) 3639, and also shear strength was measured (according to BS EN 205). The highest initial density of 0.93 g/cm 3 was for beech LVL with VTKA adhesive. After exposure to steam for 96 h, the highest weight increase of 65.7% was for poplar LVL with PVAc, the highest radial swelling of 5.7% was for beech LVL with UF, the highest tangential swelling of 7.9% was for beech LVL with PF and the highest longitudinal swelling of 0.5% was for beech LVL with VTKA. The highest shear strength value of 15.8 N/mm 2 among all samples without exposure to steam was obtained for beech LVL with PVAc adhesive and the lowest shear strength was obtained as 4.48 N/mm 2 for poplar LVL with UF adhesive.

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