SU844984A1

SU844984A1 - Method of determining interal stresses at drying wood

Info

Publication number: SU844984A1
Application number: SU792818447A
Authority: SU
Inventors: Виктор Анатольевич Мещеряков
Original assignee: Государственный Институт По Проектированиюлесопильных И Деревообрабатывающихпредприятий
Priority date: 1979-08-08
Filing date: 1979-08-08
Publication date: 1981-07-07

Description

(54) СПОСОБ ОПРЕДЕЛЕНИЯ ВНУТРЕННИХ НАПРЯЖЕНИЙ ПРИ СУШКЕ ДРЕВЕСИНЫ(54) METHOD FOR DETERMINING INTERNAL STRESSES WHEN DRYING WOOD

1one

Изобретение относитс к измерительной технике, а именно к способам определени внутренних напр жений при сушке древесины .The invention relates to a measurement technique, in particular, to methods for determining internal stresses during wood drying.

Известен способ определени внутренних напр жений при сушке древесины, заключающийс в том, что исследуемую древесину разрезают на образцы, нагружают заданной нагрузкой, измер ют деформацию и вычисл ют модуль упругости, затем образцы сушат и вновь повтор ют вышеуказанные операции и по разнице модулей упругости суд т о внутренних напр жени х 1.A known method for determining internal stresses during wood drying is that the test wood is cut into samples, loaded with a given load, the strain is measured and the elastic modulus is calculated, then the samples are dried and the above operations are repeated and judged by the difference in elastic moduli internal stress x 1.

Недостатками данного способа вл ютс его больша трудоемкость, св занна с необходимостью проведени большого числа испытаний дл набора требуемого числа данных, а также низка точность, св занна с тем, что образцы проход т сушку в услови х, отличных от условий, имеющих место во внутренних сло х неразрезанной древесины.The disadvantages of this method are its large laboriousness, due to the need to carry out a large number of tests for a set of the required number of data, as well as low accuracy, due to the fact that the samples are dried under conditions different from those that occur in the interior. layers of uncut wood.

Наиболее близким по технической сущности и достигаемому результату к изобретению вл етс способ определени внутренних напр жений при сушке древесины,The closest in technical essence and the achieved result to the invention is a method of determining internal stresses during drying of wood,

заключаюшийс в том, что исследуемый образец древесины раздел ют вдоль волокон по толшине на П-образные или П-образные с боковыми выступами, вл ющимис продолжением перекладины, силовые секции, измер ют рассто ние между концами стоек, суща.т силовые секции, и вновь определ ют рассто ние между концами стоек силовых секций, по которому определ ют внутренние напр жени 2.The test sample of wood is divided along fibers into U-shaped or U-shaped with lateral protrusions, which are a continuation of the crossbar, the power sections, measure the distance between the ends of the uprights, existing power sections, and again determine the distance between the ends of the racks of the power sections, from which the internal stresses 2 are determined.

Недостатком данного способа вл етс The disadvantage of this method is

10 сравнительно низка точность измерений, св занна с тем, что образцы проход т сушку в услови х, отличающихс от условий, имеющих место во внутренних сло х неразрезанной древесины.10, the measurement accuracy is comparatively low due to the fact that the samples are dried under conditions different from those occurring in the inner layers of uncut wood.

Целью изобретени вл етс повыщениеThe aim of the invention is to increase

15 точности измерений.15 measurement accuracy.

Claims

This goal is achieved by isolating the power sections before drying on the interfaces by a heat-impermeable layer, folding them in their original order, connecting one of their ends to each other, and others, to the force meter, to determine internal stresses. The drawing shows a circuit for carrying out a method for determining internal stresses during wood drying. The power sections D are insulated with a heat and moisture impermeable layer 2, some of their ends are fastened with a ferrule 3, and the others are connected to a load cell 5 by means of adjusting device 4. The method of determining internal stresses during wood drying is implemented as follows. The investigated wood is cut into power sections 1, which isolate the heat-tight layer 2, fold in their original order, shrink one ends of the yoke 3, and the other with the help of the adjusting device and coordinate it with the force meter 5. Remove the force meter readings, and the power sections assembled 1 with the holder 3, the setting device 4 and the load cell are placed in the chamber for the present and exist, after which the reads of the load tester are retrieved and re-recorded. According to the difference of indications, the force tester judges internal stresses in the wood. The application of the invention makes it possible to increase the measurement accuracy due to the fact that the samples are deformed together, and the internal stresses are close to the stresses in uncut wood. Claims The method for determining internal stresses during wood drying is that the test wood sample is divided along power fibers into power sections, and internal stresses are defined and characterized in that in order to increase the accuracy of measurements, power sections in front of the substrate, the heat-impermeable layer is insulated along the interfaces, is folded in the initial order, its ends are interconnected, and the others are connected to the load cell to determine internal stresses. Sources of information taken into account in the examination 1.Ugolev B.N. Internal stresses in wood during drying. M., stroiizdat, 1959, p. 54-64.

2. Guidance materials for chamber drying of sawn timber. Arkhangelsk, 1971, p. 15 fig. 2 (prototype).