scholarly journals RESEARCH OF PHYSICAL AND MECHANICAL PROPERTIES OF WOOD-FIBER MATERIALS

2020 ◽  
pp. 451-457
Author(s):  
Aleksandr Yur'yevich Vititnev ◽  
Yuriy Davydovich Alashkevich ◽  
Natal'ya Geral'dovna Chistova ◽  
Roman Aleksandrovich Marchenko ◽  
Venera Nurullovna Matygullina

This paper presents the results of experimental studies of the physical and mechanical properties of wood-fiber boards of the wet production method when regulating the design and technological parameters of the grinding process. This allowed us to determine the influence of the working clearance between the grinding discs and the concentration of fibre mass with the subject to of quality change wood fiber after defibrator using the developed construction of the disc fibrillation action on the physico-mechanical properties of boards. As a result of the experiment, regression models were obtained that adequately describe the studied grinding process and allow predicting the values of physical and mechanical properties of the finished product depending on the established  parameters process. A comparative analysis of the size and quality characteristics of the fiber semi-finished product and its fractional composition when using a developed construction the disc of refiner fibrillation action and a traditional design used in industry is carried out. The preferential efficiency of the grinding process under the fibrillating effect the disc of refiner in comparison with the traditional construction disc of refiner is established. As a result, there is a significant improvement in the quality indicators of the fiber semi-finished product and its composition due to the formation and predominance in the total mass of long and thin, respectively, flexible fibrillated fibers with high tile-forming properties, which allows to increase the strength properties of the product (by 20–25%), without using binding resins.

2020 ◽  
pp. 467-474
Author(s):  
Venera Nurullovna Matygulina ◽  
Natalya Geraldovna Chistova ◽  
Alexander Yuryevich Vititnev

Despite the reduced demand for fiber boards, research related to their manufacture is relevant, since the production of wood-based materials significantly contributes to solving the problem of the integrated use of wood raw materials. The paper presents the results of experimental studies reflecting the dependence of the strength characteristics of dry and wet wood fiber boards on the structural and technological parameters of grinding plants of various modifications. The experiments were carried out in laboratory facilities and in the production environment on existing industrial equipment. Based on the results of processing multifactor experiments implemented in a second-order B plan, a mathematical description was obtained of the dependence of the tensile strength during static bending of solid wood fiber boards of the dry and wet production method on the gap between the grinding disks, wear of the segments and the concentration of wood fiber mass. The obtained regression models are adequate to the process and can be applied in practice to predict the strength characteristics of fiberboards depending on the parameters of the grinding process. As a result of the analysis of the calculated and graphical dependences obtained on the basis of studies in the production environment on the existing equipment, it is possible to determine what parameters on the grinding equipment must be set in order to obtain the necessary physical and mechanical properties of the fiberboard.


Author(s):  
Orlov Maksim Andreyevich Et al.

The article discusses the features of the destruction of carbon fiber reinforced plastics on the basis of tfp-preforms produced using various stitching mode parameters, and provides for studies of their physical and mechanical properties and structure. The effect of the carbon fiber laying density and the piercing step of the aramid yarn on the elastic-strength properties of composites is shown. The optimal technological parameters for creating tfp-preforms of gas turbine engine blades were chosen.


2021 ◽  
pp. 102-111
Author(s):  
Andriy Paliy ◽  
Elchyn Aliiev ◽  
Anatoliy Paliy ◽  
Katerina Ishchenko ◽  
Igor Lukyanov ◽  
...  

To implement effective cow milking, it is necessary to take into account the peculiarities of the milk flow process, the milking machine's adaptability to perform the given technological functions. The aim of research is to establish changes in the design and technological parameters and physical and mechanical properties of teat cup liner of milking machines during its testing and in production conditions. The results obtained will make it possible to make a rational choice of rubber, ensure an efficient milking process during its service life. It is found that the tensile strength of silicone teat cup liner at the beginning of operation was 1.6 times higher than that of a rubber compound, and after 6 months. operation – 1.7 times. With respect to the relative elongation, this difference was 1.4 times, and after operating time – 1.3 times. Studies have proven that rubber during operation changes its physical and mechanical properties: the length of the active part increased by 3.1 mm; wall thickness – 0.2 mm. It is found that the most intensively elastic properties of teat cup liner changed during the first 10–20 days. After 10 days, the closing vacuum increased by 16.6 % compared to the initial one, and after 20 days by 23.3 %, which amounted to 8.57 and 9.06 kPa, respectively. Up to 420 hours of operation, the clamping vacuum reached 11.3 kPa, which is 5.8 % lower than the requirements for toughening teat cup liner for rejection. In general, over the period of experiments, the average value of the vacuum of closing the opposite walls of teat cup liner increased from 7.35 to 12.43 kPa, which is 3.6 % higher than the norm (12 kPa). As a result of experimental studies, the regularity of the rubber tension force depending on the operating time in the form of a fourth degree polynomial is obtained. It is found that after 150 hours of operation, the tensile force of teat cup liner decreased by 21 %


2021 ◽  
Vol 887 ◽  
pp. 110-115
Author(s):  
G.A. Sabirova ◽  
R.R. Safin ◽  
N.R. Galyavetdinov

This paper presents the findings of experimental studies of the physical and mechanical properties of wood-filled composites based on polylactide (PLA) and vegetable filler in the form of wood flour (WF) thermally modified at 200-240 °C. It also reveals the dependence of the tensile strength, impact strength, bending elastic modulus, and density of composites on the amount of wood filler and the temperature of its thermal pre-modification. We established that an increase in the concentration of the introduced filler and the degree of its heat treatment results in a decrease of the tensile strength, impact strength and density of composite materials, while with a lower binder content, thermal modification at 200 °C has a positive effect on bending elastic modulus. We also found that 40 % content of a wood filler heated to 200 °C is sufficient to maintain relatively high physical and mechanical properties of composite materials. With a higher content of a wood filler, the cost can be reduced but the quality of products made of this material may significantly deteriorate. However, depending on the application and the life cycle of this product, it is possible to develop a formulation that includes a high concentration of filler.


Filomat ◽  
2020 ◽  
Vol 34 (2) ◽  
pp. 609-614
Author(s):  
Burcu Aydin ◽  
Fusun Yalcin ◽  
Ozge Ozer ◽  
Gurhan Yalcin

Marbles are secondary decomposition products formed by metamorphism of limestone. Effective classification of marble quarries in terms of quality enables the selection of a sustainable production method and safety application. This evaluation is based on physico-mechanical properties of the samples. Obtained results of physico-mechanical properties of the marbles were statistically analyzed using Stata 14 and SPSS 21 software. The marbles indicated mostly normal physical and mechanical properties. A strong inverse relationship exists between Abrasion Value and Knoop Hardness Determination that indicates a significant nonlinear relationship. Samples were distinguished into 3 groups of close similarity and related properties. The estimated value of the parameters is in the 95 % confidence interval. The equation obtained by regression analysis was used for the determination of resistance to abrasion.


Author(s):  
Alsaid Mazen ◽  
Ali Salamekh

In the last decades there is increasing the need to apply polymer composite materials in different industries, particularly in shipbuilding. There are developing single structures made from polymer composite materials to be used on board ships. The article focuses on technology of manufacturing slabs from polymer composite materials to carry out mechanical testing in the laboratory special standard units. Mechanical properties of polymer composite materials depend on molding technologies. There has been described a technology of sample manufacturing from polymer composite materials reinforced with glass fiber mat with fiberglass plastics. The technique of testing the specified samples for tensile strength has been considered. The sizes and shapes of the samples as well as the technological parameters of the manufacturing process have been validated, depending on the standard requirements and the technological features of the testing machine. The physical and mechanical properties of the components that make up the composite materials are considered. The sequence of stacking layers for preparation of plates from composite materials is indicated. The dimensions of the plates for cutting out finished samples are determined, depending on the method of production. The way of laying plates from composite materials has been chosen on the base of economic considerations and conditions of accessibility. The obtained results of mechanical properties can be used in solving problems of application of polymer composite materials in shipbuilding, for example, in manufacturing superstructures of some dry cargo vessels.


2019 ◽  
Vol 974 ◽  
pp. 181-186
Author(s):  
V.A. Perfilov ◽  
V.V. Gabova ◽  
Inessa A. Tomareva

The effect of superplasticizing, foam agents, various fiber aggregates on the physical and mechanical properties of cellular concrete has been studied. The article covers the results of experimental studies conducted to determine the effect of foam agents PO-6 and PB-2000, as well as polymeric and basalt fiber on the pore structure of foam concrete. The dependence between the change in density and strength of cellular concrete and the structure of its pore space has been determined.


2011 ◽  
Vol 130-134 ◽  
pp. 1712-1715
Author(s):  
Gai Li Zhou ◽  
Linan Li ◽  
Shui Jiao Li ◽  
Shi Bin Wang

In order to learn the mechanical properties of deep-sea mooring lines, experimental studies involved in strength properties have been carried out in this thesis. In the fiber strength performance test, the small force-large deformation experimental device has been designed and optimized. As the fiber diameter is very small (about 40μm), microscope is chosen to measure the diameter. The intensity curve of fiber is divided into three typical phases. The yield strength, breaking strength and elastic modulus in initial stage can be calculated and the elastic modulus is basically a constant. With the increasing of loading rate, the breaking force reduces and gradually tends to stabilize. It has got the formula, breaking strength ∝.


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