Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Journal of KONES

2 Kyzioł L.

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: device to inflict plane stress

Sortuj według:

Ogranicz wyniki do:

Shear stress in measuring section of the sample with modified wood

Kyzioł L.

Journal of KONES

2016

Vol. 23, No. 1

193--198

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.

Fatigue strength of wood polymer composite

Kyzioł L.

Journal of KONES

2014

Vol. 21, No. 1

139--146

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.