SU866455A1

SU866455A1 - Wood plasticity determining method

Info

Publication number: SU866455A1
Application number: SU782615043A
Authority: SU
Inventors: Алмар Вильгельмович Берзон; Карл Артурович Роценс; Янис Янович Ратениекс; Ян Карлович Гулбис
Original assignee: Ордена Трудового Красного Знамени Институт Химии Древесины Ан Латсср
Priority date: 1978-05-10
Filing date: 1978-05-10
Publication date: 1981-09-23

Description

1one

Изобретение относитс к области определени пластических характеристик капилл рно-пористых тел и может быть использовано дл контрол процессов пластификации древесины и оценки свойств готового продукта.The invention relates to the field of determining the plastic characteristics of capillary-porous bodies and can be used to monitor the processes of plasticization of wood and assess the properties of the finished product.

Известен способ определени пластичности древесины путем нагружени образца и измерени остаточной деформации .There is a known method for determining the plasticity of wood by loading the sample and measuring the residual strain.

Недостатком известного способа . вл етс то, что значение остаточной деформации зависит от напр жени нелинейно , т.е. выбранному уровню напр жени может соответствовать люба остаточна деформаци в зависимости от пористости, температуры и влажности , что снижает достоверность измерений .The disadvantage of this method. is that the residual strain value depends on the stress non-linearly, i.e. Any residual strain can correspond to the chosen voltage level depending on porosity, temperature and humidity, which reduces the reliability of measurements.

Цель изобретени - повышение достоверности .The purpose of the invention is to increase credibility.

Указанна цель достигаетс тем, что в известном способе определени пластичности древесины путем нагруже1 ни образца и измерени остаточной деформации, нагружение образца производ т до деформации, обеспечивающей исчезновение полостей клеток сосудов. В этом случае исключаютс искажени , св занные с нелинейностью зависимости между остаточной деформацией и напр жением. Деформаци , обеспечивакица исчезновение полостей клеток сосудов, может быть определена по This goal is achieved by the fact that in a known method for determining the plasticity of wood by loading a sample and measuring residual deformation, the sample is loaded before the deformation ensures the disappearance of the vascular cell cavities. In this case, the distortions associated with the nonlinearity of the relationship between residual strain and stress are eliminated. Deformation, ensuring the disappearance of vascular cell cavities, can be determined by

10 характерному минимуму скорости распространени упругих волн в направлении сжати образца в процессе нагружеии .10 characteristic minimum speed of propagation of elastic waves in the direction of compression of the sample during the loading process.

Способ осуществл етс следующим The method is as follows.

(S образом.(S way.

Образец древесины березы размером мм помещают между ультразвуковыми преобразовател ми, подключенными к ультразвуковому детектору в A millimeter birch wood sample is placed between ultrasound transducers connected to an ultrasonic detector in

Claims

20 test press. Then the sample is loaded until a strain value is reached, at which time the propagation time is. The ultrasound pulse reaches its maximum. During this deformation, the sample is held under load for 10 minutes, after which the sample is unloaded, held for 10 minutes in the unloaded state, and the sample size is measured in the direction of loading, from which the residual strain value is determined. The residual deformation measured by the proposed method, as a measure of stumpness, more reliably characterizes the properties of wood in the manufacture of the finished product, and also makes it possible to determine the effect on ductility of wood 1 of humidity, temperature and chemical effect, which is used in determining optimal processing conditions . The invention of the method of determining the plasticity of wood by loading the sample and measuring the residual deformation, which is characterized by the fact that, in order to increase the reliability, the loading of the sample is carried out before deformation ensuring the disappearance of the vascular cell cavities. Sources of information taken into account during the examination 1. Darzins ETC. et al. Some elastic plastic properties of chemically treated wood. Sat Modification of wood, Riga, Zinatne, 1967, p. (prototype).