Temat: modified wood - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Mechano-sorptive creep of Portuguese pinewood chemically modified
Autorzy:: Lopes, D.B.
Mai, C.
Tematy:: creep factor
Portuguese pine wood
pine wood
chemically modified wood
modified wood
mechano-sorptive effect
wax
resin; Pokaż więcej
Wydawca:: Instytut Badawczy Leśnictwa
Powiązania:: https://bibliotekanauki.pl/articles/38325.pdf Link otwiera się w nowym oknie
Opis:: The effect of chemical modification on mechano-sorptive creep in bending was studied by experimental work. Stakes with 20 × 20 × 400 mm RTL of Portuguese wood species (Pinus pinaster Aiton) modified with 1,3-dimethylol-4,5- dihydroxyethyleneurea (DMDHEU), m-methylated melamine resin (MMF), tetraethoxysilane (TEOS) and amid wax (WA) were measured under asymmetric moistening conditions over a period of 42 days (app. 1000 hours) with stress level (SL) of 12 MPa, according to ENV 1156. The cell wall treatments (DMDHEU and MMF resins) had shown significant reduction of creep (creep factors, kc) when compared to untreated wood under similar conditions. Both types of resins and levels of treatments (different WPG) did not shown significant effects. In the lumen fill treatments, deposit material of TEOS did not affected the creep behaviour (kc); Wax treatment was shown a particular compliance of creep due to avoid exchange moisture (by the hydrophobic effect of wax). The anti-creep efficiency (ACE) correlated better than other mechanical or physical properties imparted by the modification process.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Determination of the material constants of composite materials on the example of modified wood
Autorzy:: Kyzioł, L.
Tematy:: modified wood
polymethylmethacrylate
homogenization
equivalent material constants; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/949515.pdf Link otwiera się w nowym oknie
Opis:: Homogenization is the transition from the level of microscopic heterogeneity to a homogeneous macroscopic level. The analysis of the value of equivalent parameters and their variability requires prior determination of the influence of microstructure on the values of these parameters [15]. Wood is a composite material and has a layered structure in the form of alternate layers of soft and hard wood. One of the main issues was the determination of constants materials of individual layers of natural wood and modified and then equivalent material constants of natural and modified wood. The material constants of single layers and the material constants of composite were determined on the basis of experimental studies. For this purpose, a homogenization method has been used to determine equivalent material constants on the basis of material constants of single layers of soft and hard wood [1, 2, 14]. A representative cell consisting of a softwood and hardwood layer has been isolated from the sample-measuring portion. On the basis of this cell have been developed mathematical model of equivalent material constants. A sample consisting of two layers was subjected to an even stretch in the direction of the axes x1, x2, x3. The equivalent material constants have been defined by using equilibrium conditions, geometric conditions, and Hooke’s generalized law. Each wood component on the micro-level is homogeneous, continuous with its constitutive equation, conservation laws, and boundary conditions at the boundary of the separation of components. The equivalent material constants of natural and modified wood have been determined using the homogenization method [12, 13]. The results obtained from the research and the results obtained from the calculations are very similar.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Drewno modyfikowane termicznie
Thermally modified wood
Autorzy:: Adamczyk-Królak, I.
Tematy:: drewno modyfikowane termicznie
fazy procesu technologicznego drewna modyfikowanego termicznie
thermally modified wood
phase of the technological process of thermally modified wood; Pokaż więcej
Wydawca:: Politechnika Częstochowska
Powiązania:: https://bibliotekanauki.pl/articles/2065156.pdf Link otwiera się w nowym oknie
Opis:: Artykuł przedstawia krótką charakterystykę drewna modyfikowanego termicznie, jego zalety i wady oraz przykłady zastosowania w praktyce na fasadach budynków mieszkalnych i użyteczności publicznej.
The article presents short characteristic of thermally modified wood, its advantages and disadvantages, and examples of application of these solutions on the facades of residential buildings and public buildings.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Method of determining the structural parameters of wood-polymer composite
Autorzy:: Kyzioł, L.
Murawski, L.
Tematy:: modified wood
wood-polymer composite
methyl methacrylate
material constants
soft layers, hard layers; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/242880.pdf Link otwiera się w nowym oknie
Opis:: A composite material consisting of woody skeleton and polymerized methacrylate has been developed and characterized. This paper presents an experimental program and the results concerning mechanical properties and strength of wood modified with polymerized methacrylate. In the article, there are examples of structural elements made of natural wood. Wood is a composite consisting of the layers of soft and hard wood. Wood is a composite and porous material. The porosity, which is a serious defect of wood, may be simultaneously its advantage. Wood saturation with different impregnates to minimize its disadvantages. If the wood pores will fill the monomer there is obtained the wood polymer composite. This composite is classified as of fiber composites. Such composite is effectively protected against degradation; it is durable in use, and show an improvement in mechanical properties. Design constructions of surface modified wood require the determination of fundamental material constants. Therefore, for the determination of these parameters is very important obtaining the appropriate research material. The surface impregnation of wood allows obtaining strength characteristics in a function of polymer content. This allows to model it's, and then design and perform specific ship structures. In the wood, there are three directions in relation to the annual rings. Wood properties, especially mechanical properties, are different in the selected directions. For the computation takes the orthogonal anisotropy in which there are three mutually orthogonal planes of symmetry, for which there is symmetry properties of the wood.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Composite materials for warship constructions
Autorzy:: Kyzioł, Lesław
Tematy:: polyester-glass composites
recyclate
modified wood
non-magnetic warships isotropic; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/245851.pdf Link otwiera się w nowym oknie
Opis:: The article presents the basic properties of composite materials used for the construction of special ships. Static and dynamic characteristics of materials such as wood and polyester-glass composites are presented. Noteworthy are materials such as surface modified wood and polyester-glass composites with the addition of recyclate. Composite materials are widely used materials for the construction of non-magnetic warships. The article describes the properties of surface modified wood with polymethyl methacrylate and a polyester-glass composite with the addition of recyclate. The recyclate is fragmented, milled polyester-glass scrap. The content of the recyclate greatly affects the mechanical properties of the composite. The properties of the composite with the addition of recyclate depend on the recyclate content as well as the production technology and size of the recycled granulates. The test results showed that the increase in the recycled content causes a decrease in the mechanical properties of the composite. However, it should be remembered that these materials originated from waste, waste that is not subject to self-degradation, which have a very negative impact on the natural environment. At present, where there is a very large pollution of the natural environment, the processing and management of huge amounts of composite waste is an essential goal. A significant amount of recyclate significantly reduces the mechanical properties of the composite; however, the same large amount of recycled material has been transformed and used. The manufactured material and its structural elements are still non-magnetic structures and can be used on a less loaded element. The choice of material for the construction of special ships elements is determined not only by its properties but also by knowledge, experience, method of processing, economic and technical risk.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Fatigue strength of wood polymer composite
Autorzy:: Kyzioł, L.
Tematy:: modified wood
mechanical properties
fatigue strength
device to inflict plane stress; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/242494.pdf Link otwiera się w nowym oknie
Opis:: This paper presents the results of a study on the fatigue strength in pendulum bending natural and modified pinewood. The contents of polymethyl methacrylate (PMMA) were determined in wood-polymer for mechanical and rheological properties. The study of the bending fatigue strength and creep was realized on suitably prepared samples and research positions. Test results were documented in the form of charts and scraps. Differences in the decay of the natural and modified wood samples were observed after the attempt of the fatigue strength. The various mechanical properties of the sapwood, hardwood, and the polymer, influence on the stiffness of the individual components and consequently the whole composite. The process of fatigue degrades the structure of natural wood and wood polymer composite, the result is a gradual reduction of its stiffness. The Study of the creep behaviour was realized in stress in the sample of the level of 30% of the tensile strength. The samples were loaded longitudinally and transversely to the direction of the fibres. Significant differences of composite deformations were observed both as for the direction of the loaded fibres as well as the natural and modified wood. The character of changes in the fatigue strength and creep behaviour of the studied materials is implies to the influence of the polymer content on mechanical properties of modified wood. The tests carried out on account of the possibility of using wood polymer composite in sea constructions. Research carried out in connection with the possibility of the use of wood polymer composite marine construction. Modified wood can be used for keel blocks, decks, fender beam, bearings cantilevered shaft lines and the construction of yachts.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Shear stress in measuring section of the sample with modified wood
Autorzy:: Kyzioł, L.
Tematy:: modified wood
mechanical properties
Iosipescu shear test
device to inflict plane stress; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/242608.pdf Link otwiera się w nowym oknie
Opis:: The shear strength of anisotropic materials is carried out on the special samples and on the appropriate instrumentation. Research conducted to obtain a homogenous state of the shear stress in the plane sample is difficult, and involve numerous occurrence of additional stress. Therefore, it is difficult to determine the shear strength. The wood composites are classified as orthotropic materials. In addition, are composed of the layers early wood and latewood. The layers have different thicknesses and exhibit different strength properties. The principal method for determining the shear stress is the trial of twisting of thin-walled tubes. Production of the pipe samples from the wood to determine the shear stress is impossible, due to annual rings. Beginning of destruction of samples under load was registered by a prototype device. This device makes the realization of plane state of stress in the sample possible. The position of the axis of the sample relative to the direction of the load can be varied. Such configuration axle of the sample to the loading direction, allows to perform, also stretching or compression besides to shear. The tests were performed for the natural wood and surface modified wood. The paper presents an original method and device designed to determine the shear strength of anisotropic materials on the example of natural wood and a surface modified wood.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Description of strength of wood composite in compound state of load
Autorzy:: Kyzioł, L.
Tematy:: compound state of stress
modified wood
effort criterion
strengthening of the material; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/950148.pdf Link otwiera się w nowym oknie
Opis:: All constructions are subject to the most compound loads and therefore a suitable effort hypothesis should be used for their calculation. For anisotropic materials, a hypothesis should be used to describe the properties of such materials. In the work have been shown the strength of the layers composite on the example of construction wood in a compound stress state. Wood composite is an orthotropic material. Wood is composed of alternating layers of soft wood and hard wood. Single layers are monotropic material. The use of a stress hypothesis, which describes the strength of an orthotropic material, requires will make an investigation. Studies is purposed to determine the tensile strength along and across the fibres. The compressive strengths along and across the fibres and the shear strength. Particularly the determination of shear strength requires special tooling so that in the case of flat samples in the measuring part it is possible to determine the shear stresses. Therefore, a research stand was designed and constructed. Known stress hypotheses for anisotropic materials have been analysed. The analysis showed that the strength of the wood composite could be described by the Tai-Wu stress hypothesis. Based on the results of the research, numerical calculations were performed. Calculations allowed determining the distribution of stresses in the sample measuring part. The results tests and numerical calculations have shown that obtaining a homogeneous stress (shear) condition for anisotropic materials is very difficult. Wood belongs to materials whose mechanical properties depend on many parameters, so the description of the effort of this material is a compound issue. Studies have shown that wood reinforcement by polymer saturation is best suited to the compressed loaded structures.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Odporność na pękanie drewna modyfikowanego powierzchniowo
The fracture toughness of the modified wood surface
Autorzy:: Kyzioł, L.
Tematy:: materiały kompozytowe
odporność na pękanie
drewno modyfikowane powierzchniowo
composite materials
cracking resistance
modified wood surface; Pokaż więcej
Wydawca:: Instytut Naukowo-Wydawniczy "SPATIUM"
Powiązania:: https://bibliotekanauki.pl/articles/312211.pdf Link otwiera się w nowym oknie
Opis:: Ważną cechą materiałów kompozytowych jest ich odporność na pękanie. Często spotykane są przypadki nagłego pękania elementów pomimo tego, że naprężenia nie przekroczyły wartości dopuszczalnych. Pękanie materiału z którego zbudowana jest konstrukcja przyczynia się nie tylko do strat ekonomicznych, ale często prowadzi do wypadków śmiertelnych. Dlatego też projektowanie zabezpieczające konstrukcje przed utratą spójności jest bardzo ważne. W pracy podjęto zagadnienie dotyczące określenia związków ilościowych pomiędzy odpornością na pękanie drewna naturalnego i modyfikowanego w określonych warunkach obciążenia, a wielkością wady. Przedstawiono wpływ zawartości polimeru na odporność na pękanie kompozytu drewno – polimetakrylan metylu. Podano sposoby określania siły krytycznej i możliwości określenia odporności na pękanie drewna naturalnego i modyfikowanego dla wybranych kierunków anatomicznych. Wykazano znaczny wzrost odporności na pękanie drewna powierzchniowo modyfikowanego w stosunku do drewna naturalnego.
The fracture toughness is an important feature of composite materials. There are often cases of sudden rupture of elements, despite the fact that the stresses do not exceed the limit values. The cracking of the material is the cause of economic loss and often leads to fatal accidents. Therefore, designing hedging structures against the loss of cohesion is very important. This paper presents the quantitative relation-ships between fracture toughness of modified wood and natural in certain load conditions, and the size of the defect. The influence of polymer content on the fracture strength of the composite wood - polymethyl methacrylate was presented in the work. Methods for determining the critical force and toughness of natural wood and modified with the selected anatomical orientations are presented. The article demonstrated a significant increase in resistance to fracture of the wood surface modified with respect to natural wood.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Wytrzymałość drewna modyfikowanego w złożonych stanach naprężeń. Część II. Opis matematyczny
Modified wood strength under complex tension conditions. Part II. Mathematical descritption
Autorzy:: Kyzioł, L.
Tematy:: drewno naturalne i modyfikowane
wytrzymałość graniczna
kryteria wytrzymałościowe
natural and modified wood
boundary strength
strength criteria; Pokaż więcej
Wydawca:: Akademia Marynarki Wojennej. Wydział Dowodzenia i Operacji Morskich
Powiązania:: https://bibliotekanauki.pl/articles/222566.pdf Link otwiera się w nowym oknie
Opis:: W pracy przedstawiono powierzchnie graniczne wytrzymałości drewna naturalnego i modyfikowanego w oparciu o wyniki badań wytrzymałościowych zawartych w części I. Do opisu wytrzymałości badanych materiałów w złożonych stanach naprężeń wykorzystano kryterium wytężenia Tsai-Wu oraz Goldenblata-Kopnova. Weryfikację ich adekwatności przeprowadzono na podstawie testu F Sendocora.
The paper presents boundary surfaces of natural and modified wood strength based on the results of investigations into strength included in Part I. To describe strength of the materials under investigated under complex tension conditions Tsai-Wu and Goldenblata-Kopnov criteria were used. Sendocor's test F heir was used to verify their adequacy.
Dostawca treści:: Biblioteka Nauki

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