In modern conditions, one of the significant obstacles to ensuring increased power, efficiency and resource of military and civilian vehicles is the exhausted possibilities of traditional technical solutions of basic elements and systems. This primarily applies to high-speed elements, in particular, turbines and rotary parts of air blowers of internal combustion engines, transmissions, drives, hydraulic machines and more. High speeds cause dynamic processes that can potentially lead to problems with strength, rigidity and stability. In order to substantiate the progressive technical solutions of high-speed parts, it is necessary to develop appropriate theoretical foundations for the analysis of processes that occur in these elements. The stress-strain state of the elements of rotor systems is of particular interest. It is also important to determine the stiffness properties of the elastic supports. In turn, this affects the stability of the rotor systems. This creates a basis for establishing patterns of influence of variable parameters on the characteristics of dynamic processes and states. A complex mathematical and numerical models of the stress-strain state and stability of motion of high-speed structural elements is developed on a unified  methodological basis. These models are described by a common set of varied parameters. General criteria and restrictions are formulated. The search for advanced solutions is carried out by meeting certain complex criteria and constraints. Design parameters and operational modes are varied. The analysis problems are solved using a unified parametric model. Keywords: civil and military machines, RPM structural parts, stress-strain state, critical rotational velocity

In this work, on the development of previous research, a model of contact interaction of similar shape bodies is built. Contact in the system "punch - stamped material - matrix" is considered. A gap is set between the material to be stamped and the matrix, which varies in circular coordinate. The regularities of the change of contact pressure and contact areas with variation of the law of distribution of the initial gap are determined. The influence of the load level on these parameters is also determined. In particular, the analysis of the influence of the number of waves in the distribution of the initial gap in the circular direction on the nature of the distribution of contact areas and contact pressure. It is established that at low level of loads significant non-uniformity of the contact pressure distribution along the circular coordinate is realized. In the future, with increasing load levels, this unevenness decreases. The distribution of contact pressure tends to the case of contact with nominally coincident surfaces of the matrix and the material to be stamped, i.e. at zero gap. Thus, an analytical-numerical method for studying the contact interaction of closely shaped bodies with low perturbation of the initial gap distribution has been developed. Regularities of influence of constructive and technological parameters on contact interaction of these bodies on an example of elements of stamp equipment are also established. Keywords: contact interaction; stress-strain state; elements of stamps; contact area; contact pressure

The stress-strain state and critical rotation speeds of the air blower rotor part of highly forced engine are investigated. For this purpose, their parametric geometric and finite-element models are built. Due to the high speeds of rotation, the impeller disk acquires an umbrella-shaped deformed shape. This deformation can cause a gap to be selected between the impellers and the stator of the supercharger. In areas of abrupt change of shape on the impeller there is a concentration of stresses. In addition, the supercharger impeller is located cantilevered. This causes low critical speeds. These frequencies may fall within the operating range of angular velocities of the supercharger rotor. All these factors in the complex within a single calculation model were not previously taken into account. Instead, taking into account the dependences of stress, strain and critical velocity levels on the design parameters is of interest in the development of supercharger designs. In particular, the stiffness characteristics of the elastic rotor bearings were varied. The influence of these parameters on the critical rotation speeds of the rotor part of the air supercharger is determined. Recommendations have been developed for debugging from hazardous supercharger modes. In particular, it is proposed to reduce the radial stiffness of the shaft bearings by using elastic flexible rings. This can reduce critical rotor velocities beyond the operating range. In addition, a lighter material can be used to increase the strength of the impeller. It is also possible to limit the operating range of the angular rotational velocities of the rotor part of the investigated air blower. Analysis of the stress-strain state and the critical rotational velocities of the rotor were carried out on the basis of a unified generalized mathematical and numerical model. Keywords: rotor system, air blower, impeller, stress-strain state, critical rotation speed

The paper describes studies of the stress-strain state of power hydraulic cylinders elements. Geometric dimensions of casing and properties of materials are chosen as varied parameters. The controlled values are the levels of stresses and displacements. The criteria are weight, strength and rigidity. These characteristics determine the technical characteristics of power hydraulic cylinders. Dependences of criterion characteristics on varied parameters are established. On this basis, recommendations for substantiation of design and technological solutions of power hydraulic cylinders elements are developed. This made it possible to develop a project and technology for the manufacture of power cylinders with low material consumption. In addition, increased efficiency is provided due to the use of antifriction coating on the inner surface of cylinder. The stress level in the main material of cylinder body is limited. The strength of the area of the brazed joint material and the plastic lining layer is also ensured. A special configuration of the sealing ring is used to reduce the level of losses in the movable connection of the piston with the hydraulic cylinder body. At the same time radial displacements of the cylinder body provide acceptable contact of the moving and fixed parts of the hydraulic cylinder. In general, balanced design and technological solutions of power hydraulic cylinders elements are substantiated. They provide high technical characteristics of power hydraulic cylinders. It also increases the technological level of their production and reduces the total cost. Power hydraulic cylinders with reasonable parameters are used in the elements of technological systems. Keywords: hydraulic cylinder; finite element method; stress-strain state; computational-experimental justification

In order to substantiate the advanced technical solutions of radial hydrovolume transmissions, it is necessary to study the stress-strain state of their most responsible and loaded elements. In particular, it is of interest to determine the rational parameters of cylinder block, which is subject to significant pressure of working fluid. This leads to the formation of a stress-strain state with a high level of stresses and elastic displacements. They can be dangerous in terms of strength, rigidity and performance of the hydraulic transmission in general. To carry out numerical studies of the stress-strain state of cylinder block of hydrovolume transmission at the design stage, finite element models with varied parameters are developed. However, at this stage of research, it is desirable to have a verified numerical model. For this purpose, the paper describes the computational and experimental studies of the layout of the cyclic part of the hydrovolume transmission cylinder block. On the one hand, these studies were performed using the experimental method of holographic interferometry. On the other hand, calculations were performed using the finite element method. In the course of comparison of the received results, the finite element model parameters are determined which provide high accuracy of the stress-strain state calculation of hydrovolume transmissions cylinder block. Keywords: stress-strain state; hydrovolume transmission; finite element method; cylinder block