АНАЛІЗ СИЛ ФУНКЦІОНУВАННЯ ВІД’ЄМНОЇ ЧАСТИНИ КРИЛА ЛІТАКА ТРАНСПОРТНОЇ КАТЕГОРІЇ

Each experimental design department has experience in determining design and operational loads for a given type of aircraft. The reliability of the data on the loading of a particular structural element determines the success of the aircraft being created. This is often confidential information. Much work has been investigated to improve the fatigue life of wing structural elements. With the development of integrated design methods, aircraft structure design can be performed in the shortest time, and with high technical excellence. In most cases, the fatigue life of wing elements is determined from the nominal stresses in the element. For a longitudinal structure set, it is customary to perform fatigue calculations directly using normal stresses in the element. For a more detailed specification of the fatigue life, it is necessary to have a general and local stress-strain state of a given structure. A feature of the work is to analyze the spectrum of loads acting on the wing console during a typical flight. The influence of high-lift devises (slats, flaps) on the shear forces and torque moment of the wing was analyzed. It has been shown that with the extensions high-lift devices, there is a significant increase in torque. These articles will make it possible to obtain the stress distribution of the detachable part of the wing under all operating modes. This, in turn, leads to a more thorough prediction of fatigue life. Since some operating loads can significantly change the distribution of the stress-strain state in the design element, and in turn change the fatigue life. The structural elements of the wing, in particular the attachment points for the high-lift devices, operate in a complex-stressed state. This complicates the process of predicting the fatigue life of these elements. To obtain a competitive aircraft, it is necessary to develop new methods of wing design with widespread use of integrated systems. This will contribute to obtaining a more optimal and perfect wing design

INFLUENCE OF TEST CONDITIONS ON STRENGTH PROPERTIES OF THIN-WALL RUBBER PRODUCTS

A computer simulation of the loading of the rubber membrane by a spherical indenter is performed using a finite element analysis package. It is shown that in the complex stress state rubber based on crystallize rubber IR are significantly inferior in strength properties as in the absence and in the presence of stress concentrator to rubber based on amorphous rubber SBR, while in uniaxial tension they are superior. It is revealed that in the complex stress state, rubbers based on IR rubber filled with 40 parts by weight of carbon black N339 have low resistance to shear stresses, inferior to SBR and BR vulcanizates, which results in low strength properties of rubbers based on it in comparison with strength characteristics determined under uniaxial tension. An analysis of the strength properties of rubbers in the presence of a stress concentrator shows that in a complex stress state, rubbers based on amorphous SBR rubber have the maximum tear resistance, exceeding IR and BR vulcanizates by this indicator, respectively by ~ 4 and 2 times. Under uniaxial tension, the most important factor is the ability of the material to orientation hardening, due to the regularity of the rubber structure and the presence of reinforcing filler, and in the complex-stressed state, the most important factor is a density of the nodes of the fluctuation mesh from the point of view of strength properties.

Complex spectral-acoustic monitoring of the state of fluid-saturated coal-rock mass

Subject of the research is the methods for monitoring properties and state of coal-rock massif. This work is an experimental validation of the studied parameters of acoustic emission occurred during destruction of the roadway roof. Elements of the theory of acoustic emission control, research methods, results and experimental studies of the fluid-saturated rock destruction were studied. In this article, methods of studying and interpreting the results of geophysical observations of the process of the roof rock stratification and fall at caving of the undermined rocks at a complex stressed state are presented. Biseds, approaches to solving the problems of managing and controlling the dynamics of changes in the stress-strain state of the undermined fluid-saturated coal-rock massif based on factors of autocorrelation between the seismic-acoustic phenomena occurred over time are described. Experimental grounds are given to the complex control methods with determination of the level of disintegration by the Fourier estimation of the amplitude-frequency and amplitude-time spectra.

AN INFLUENCE OF TEST CONDITIONS ON STRUCTURAL CHANGES OF RUBBER MEMBRANES BASED ON AMORPHOUS AND CRYSTALLINE POLYMERS

The most important task of the rubber industry is the continuous improvement of the quality, reliability and durability of products, including rubber membranes, which are widely used in the automotive, aviation, machine tool, chemical and other industries. Membranes in most cases are operated in difficult loading conditions, which leads to a variety of zones and the nature of potential damage that occurs during their operation. At the same time, when developing a new rubber compounds for membranes, most often the standard methods for determining the mechanical characteristics of rubbers are used, most of which involve testing the material under simple uniaxial tension-compression and do not take into account structural changes in the material during loading. In this work, a study of structural changes in the membranes under loading in a complex stressed state, which was realized by indenting the rubber membrane with a spherical indenter, was conducted. Structural changes were evaluated by hydrostatic weighing. It has been established that in the complex stressed state of rubber based on crystallizing IR rubber, there is no distinct advantage over rubber based on amorphous SBR rubber. Indentation suppresses orientation processes in rubbers based on IR crystallizing rubber, which leads to a significant decrease in their strength properties.

Creep of isotropic homogeneous and nonaging of linear-viscoelastic materials under the complex stress state

The relaxation of isotropic homogeneous and non-aging linear-viscoelastic materials under conditions of complex stress state is considered. Thin-walled tubular specimens of High Density Polyethylene (HDPE) for creep under a single-axial stretching, with a pure twist and combined load tension and torsion are considered as base experiments, tests. The solution is obtained by generalizing the initial one-dimensional viscoelasticity model to a complex stressed state, constructed using the hypothesis of the proportionality of deviators. The heredity kernels are given by the Rabotnov’s fractional-exponential function. The dependence between the kernels of intensity and volumetric creep is established, which determine the scalar properties of linear viscoelastic materials in the conditions of a complex stressed state in the defining equations of the type of equations of small elastic-plastic deformations, and the kernels of longitudinal and transverse creep defining the hereditary properties of linear-viscoelastic materials under the conditions of the uniaxial tension. The problems of stress relaxation calculation of thin walled tubes under combined tension with torsion have been solved and experimentally approved.

Testing of Thin-Walled Tubular Workpieces

In accordance with the Russian Federation State program called “Industrial growth and improving competitiveness” it becomes more wide-spread to use thin-walled makes for pieces, modern materials with new treating methods in mechanical engineering, in automobile production and modern aviation industry. As well as requirements for quality and mechanical characteristics of finished products constantly grow. In relation to these standards, methods of intensive irreversible deformation under conditions of complex stressed state are used with increasing frequency. Study of the following parameters has a great practical importance: loaded capability of the makes during exploitation and work material strength performance under complex production process. Such strain tasks are frequently counted as most complex and demand experimental verification because of geometric and physical task nonlinearity.The current study proposes testing method for thin-walled tubular workpieces which combines implementation simplicity with a wide range of strain-stressed state charts.

Problems of Realization of Static-Dynamic Technologies and Ways of their Solution

The paper presents examples of use of the created actuators in engineering - development of various test equipment including that for the needs of space materials-science (devices for measuring of hardness, devices for testing of samples in the conditions of the complex stressed state, testing of assembling joints and others); deforming equipment and devices (presses, dies for cutting - punching, calibration and others); devices used for elimination of consequences of hazard situations.