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...

The effect of chipboard screw sizes on screw withdrawal strength was investigated using different screw insertion technique. Large diameter chipboard screw has a thicker screw thread depth than small size chipboard screw. If large chipboard screw tested on screw withdrawal test, then it will have significantly higher screw withdrawal strength than smaller chipboard screw because it will have better particle grip during screw insertion. The objective of this study is to determine screw withdrawal strength of three difference sizes chipboard screw using different types of screw insertion technique; self-drilling, pilot-hole and P+CSK insertion technique. Screw withdrawal strength of different sizes of chipboard screw was measured through its resistance after insertion to the particleboard panel using different style of screw insertion technique. Results obtained shows that the best practice for screw selection was based on screw insertion technique. Samples from three different screw sizes with self-drilling screw insertion technique have met the minimum requirement of screw withdrawal strength. Smaller chipboard screw which is 3.5M CS has the highest screw withdrawal strength when applied with self-drilling screw insertion technique. However, this small diameter of chipboard screw did not meet minimum standard requirement when applied with both screw insertion technique which used pilot-hole pre-drilling; pilot-hole and P+CSK screw insertion technique. The result shows only large chipboard screw applied with pilot-hole insertion technique has better screw withdrawal strength compared to small chipboard screw. There is no significant different of screw withdrawal strength for self-drilling screw insertion technique. This suggests that chipboard screw sizes or screw thread depth did not affect the screw withdrawal strength unless it was applied with pilot-hole pre-drilling.

The effect of adding waste polyethylene (WPE) was investigated at various ratios on some physical and mechanical properties of oriented strand board (OSB) panels. All of the test panels were bonded with 6% phenolformaldehyde resin in three layers. The manufacturing parameters was 0/100, 10/90, 20/80, 30/70, 40/60, and 50/50 by weight% of WPE/wood strand. All the boards were manufactured to achieve targeted specific gravity of 0.65 g/cm 3 . Polyethylene improved the water resistance of the OSB panels because of its hydrophobicity. Based on the results of this study, thickness swelling, humidity, dimensional stability, water absorption, and screw withdrawal resistance of the samples were improved significantly. However, MOE, MOR, and internal bond strength values of the samples decreased with increasing WPE in the panels when compared to the control panels but met minimum requirements in EN 300 (type 1-2-3-4) control panels. The conclusion was reached that waste polyethylene can be used in the manufacture of OSB panels, resulting in the enhancement of above mentioned physical and mechanical properties, as well as a safe disposal and economical utilization.

Background: Wooden materials have been among the basic materials used in many different areas due to some advantages throughout the history. Roadside barriers, which are called passive safety structures, can be produced with different materials such as wood, steel, concrete, and plastic. In this study, Renewable Hybrid Barriers (RHB), a new type of barrier that is used wood in terms of aesthetics, renewability, high shock resistance, and used sand in terms of impact absorption capacity and low cost, produced by taking into account some of the disadvantages of other barrier types. These barriers are planned to be used especially in historical/touristic areas, scenic roads, and in urban areas as urban furniture. Real-time crash tests in accordance with EN 1317 (Road Restraint Systems) standard require high cost and long time. Therefore, the pendulum crash test mechanism frequently used in the literature was manufactured at which the experiments were carried out. Results:The results revealed that the RHBs which has 2 cm thick timber and sand used together, were sufficient and suitable in terms of both cost and necessary safety criteria. It was observed that impregnation and heat treatment applications did not have a considerable negative effect on the performance of RHBs which provide an opportunity to use RHBs for outdoor conditions.. Conclusion:In the light of the results of the study, the optimum wood timber thickness was determined as 2 cm regarding TB 31 test criteria. It is proposed that the crash tests for different wood species, timber thickness, and/or barrier dimensions should carry out in future studies. This study can serve as the basis for the next step, real-time real crash tests. Since the study includes an interdisciplinary subject, it is thought that it will inspire different studies.

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