Influencing Factors And Analysis Of Air Dry Density Measure Ment By Drainage Method

Wood air dry density refers to the wood in the atmospheric conditions,dry,to dry state when the weight to volume ratio.Wood air dry density is one of the most basic physical properties of wood,which has an indelible effect on the quality of wood and the quality of wood.Based on the national standard “Method of measuring the air dry density of wood”(GB/T 1933-2009),the influence factors of the dry weight of wood in the actual measurement were analyzed by analyzing the experimental process and the test results.In this paper,the main factors influencing the experimental results were extracted by the method of drainage method in measuring the air dry density of wood,and the two main coniferous woods,Pinus massoniana and three broadleaved woods were used as the starting point.C urcuma and Walnut were selected as the object of study.The volume of the sample was measured by the method of drainage.The thickness of the specimen was measured by the method of drainage,The results show that the optimal leve l of each factor is obtained by using regression to fit the functional relationship between the results in the global range and the factors.Through the study of the influencing factors of wood dry weight measurement method,the experimental parameters were determined,the steps of the determination and the influence of each factor on the results were studied,and the stability and accuracy of wood dry density measurement were improved.,Wood identification and timber use to lay the foundation.Thereby increasing the accuracy of the various parameters involved in the wood dry density.Research indicates:(1)The coating method has a significant effect on the air dry density of the wood by the drainage method.The thin wax film layer is formed on the surface of the sample so that the measured volume is too large and the density is too small.(2)The water temperature has an effect on the dry weight of wood by the drainage method,and the result of 20 ? water temperature is the closest to the measured value.(3)The moisture content of wood has no significant effect on the air dry density of wood.However,the water content is 12%,and the measured results are close to the measured values.(4)The operation time had a significant effect on the dry weight of wood by the drainage method,the shorter the operation time,the smaller the effect on the results.(5)The wood pore structure had an effect on the dry weight of the wood by the drainage method,and the effect of the needle and the broadwood was different.(6)From the response surface test results,the response value exists the maximum value,can be obtained by the drainage method to determine the optimal air dry density: the water temperature is 20?,the operation time is 3min,the water content is 12%.