Finger-jointed lumber production has now become the most extensively used method for spliced lumbers jointing together *** properties of finger-jointed lumber are affected by many different factors such as the *** mai...
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Finger-jointed lumber production has now become the most extensively used method for spliced lumbers jointing together *** properties of finger-jointed lumber are affected by many different factors such as the *** main mechanical properties to be tested for struc-tural use finger-jointed lumber include the modulus of elasticity in static bending and the bending *** most commonly used method for testing these properties at present is the experi-mental *** this study,we used finite element method to investigate the end-pressure range,the modulus of elasticity in static bending and the bending strength for Pinus sylvistriv ***-jointed lumber under three different fitness ratios(0 mm,0.1 mm,0.3 mm).With finite element analysis(FEA)modelling results compared with the experimental test results,it is possible to find the relationship between these two kinds of results and use the FEA to predict the properties of finger-jointed *** FEA applied in the end pressure tests showed a narrower range com-pared with the modelling *** indicated that the FEA could be used in the prediction of the end pressure for finger-jointed *** modelling results for modulus of elasticity(MOE)test and bending strength(MOR)test showed about 20%discrepancies compared with the experimen-tal ***,the MOE modelling results showed the same trend as experimental results under three different fitness levels while the MOR modelling results showed the different *** can be concluded that the FEA is a feasible way in analysing the properties of finger-jointed lumber if the errors could be eliminated *** modifications should be made in order to realize the prediction of the properties of finger-jointed lumber more accurately.
The aricle presents the results of a research performed in order to establish whether drying lumber from frozen state (in winter) has repercussions upon its properties, compared to drying under the same conditions lum...
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The aricle presents the results of a research performed in order to establish whether drying lumber from frozen state (in winter) has repercussions upon its properties, compared to drying under the same conditions lumber parts originating from the same log and position within the log section but that were not frozen prior to drying. To this purpose, spruce (Picea abies L.) lumber specimens, 35mm and 55mm thick, cut from the same log, half frozen at-30 degrees C and half unfrozen, were dried under the same conditions in a climate chamber. Some mechanical properties (hardness, bending strength, and moduluselasticity in staticbending), as well as workability (expressed by means of the absorbed power and specific resistance to cutting during milling), were determined The results revealed slight differences between the frozen and the unfrozen samples both during the drying process and afterwards. It was noticed that a significant amount of water was removed from wood during the very beginning of the heating phase (thawing). With regards to wood properties after drying, a slight lowering of the mechanical properties and better workability could be established for the initially frozen samples.
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