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Methods for strengthening building structures with composite materials are considered. The reduced characteristics of a multilayer composite material are determined depending on the orientation of the layers. The criteria for the destruction of a multilayer composite material used in many areas, including construction, are considered. Unlike a homogeneous material, the bearing capacity of which is determined by the ratio of the allowable stress to the effective stress in the elements of the building and structure. The failure criteria for a multilayer composite material is defined as the ratio of the effective stress to the allowable stress. At present, many criteria for the destruction of multilayer materials have been developed and tested. In the developed criteria, exceeding the permissible strength characteristics in one of the layers of the multilayer material leads to the destruction of the multilayer material as a whole. An example of calculation of a multilayer composite material is given. As a result, the layer, type, direction of load, and failure criterion are determined, which lead to the destruction of the multilayer composite material. In this study, cases of reinforced concrete structures reinforcement with composite sheets to increase strength and reinforcement of building materials from lightweight concrete subjected to bending loads are considered. An analysis of the results obtained is carried ou.

In the present study, a robotic system is considered: a multi-stage semi-natural simulation stand. The stand is designed to simulate the flight characteristics of aircraft instruments in laboratory conditions. The use of such stands can significantly reduce the cost of developing and testing aircraft instruments and contains all the attributes of robotic systems, which allows the developed method of computer modeling and analysis of stands to be applied in the field of robotic systems. The problem is solved by the finite element method. As a result of the study, a technique has been developed for approximating parts that carry out movements: gear rims, bearings, gearboxes, motors in the finite element method. Comparison with the available experimental studies showed the effectiveness of the developed methodology. As the stand material, a composite material is used, which has a high specific strength, which makes it possible to change the physical and mechanical characteristics depending on the location of the composite base in the layers of the multilayer composite structure. A technique has been developed for arranging the base layers in a multilayer composite to obtain maximum strength and rigidity of the stand, which is one of the main factors in the efficiency of the stand. The analysis of the behavior and stress-strain state of the bench under dynamic impact has been carried out.

Cellular concrete, such as gas silicate or foam concrete, has good thermal performance and is widely used in modern construction. Possessing acceptable parameters for compression, cellular concrete has low tensile and shear characteristics. This leads to the appearance of cracks in building structures made of cellular concrete, such as partitions, interior walls, etc. Therefore, solving the problems of increasing the bearing capacity of cellular concrete is important and relevant. The purpose of this study is to study the increase in the bearing capacity of cellular concrete reinforced with composite materials under the action of temperature and bending moments. The problem is solved by the finite element method and analytical methods. As a result of the work carried out, the characteristics of wall panels reinforced with composite rods were obtained under the action of temperature and bending moments in structure. Composite materials in the form of canvases are widely used to enhance the bearing capacity of aged reinforced concrete structures or those that have received defects due to man-made impacts. Consideration of methods for determining the given characteristics of a multilayer composite canvas is necessary for conducting a study of the bearing capacity of reinforced concrete structures reinforced with composite canvases or canvases. In this paper, methods are presented for determining the given characteristics of multilayer composite canvases and panels with different arrangements of the base layers. The analysis of the obtained results showed that reinforcement of the composite materials can significantly increase the tensile strength and shear of the gas silicate of the building.

The methods of designing and modeling dynamic stands from a composite material are considered. One of the complex elements of the stands is the elements that ensure the dynamic behavior of the channels of the stand: bearing supports, gear rims, gearboxes, motors, servo drives, etc. Approximation of these elements in numerical methods for calculating and studying dynamic structures (finite element method) is a difficult task. Direct approximation of these elements does not satisfy the adequacy. Various approaches are used to adequately approximate such elements. In this paper, a methodology is proposed that consists in determining the rigidity parameters of bearing supports, gear rims, gearboxes and motors. In the future, these elements are replaced by rod systems corresponding to the replaced elements in terms of stiffness parameters. The effectiveness of the proposed method is confirmed by a comparison with of available experimental methods. The shell structures and stands were modeled in ANSYS modeling module. The considered methods for designing stands can be applied to robotic systems, weaving machines and dynamic systems for various purposes, since they contain all the elements inherent in the considered stand. The finite element approximation of the stand was carried out by elements of various types.

The robotic system is considered as a rack made of composite material, which is under dynamic influence. A method for determining the reduced characteristics of a multilayer composite material is given. The simulation of the stand was carried out. To approximate the details of the movement of bench channels: bearings, gearboxes, gear rims, motors, an algorithm and a program for calculating the rigidity of these structures have been developed in order to approximate these elements in the finite element method by replacing such elements with a system of rod structures with rigidity identical to the replaced structures: bearings, gear crowns, gearboxes, motors. The convergence of the calculation results is checked by thickening the finite element mesh. The pinching along the base of the stand was taken as the boundary conditions. A technique has been developed for modeling a three-layer stand structure. The technique for modeling a three-layer structure consists in modeling a stand, assigning filler material to it, and creating shell bearing layers on the surface of the stand, assigning it the characteristics of a multilayer composite material. A layer-by-layer stress-strain state of a stand made of composite material has been obtained. The analysis of the influence of the orientation of the layers of a five-layer composite material on the stress-strain state of the HIL simulation bench has been carried out.

The paper developed a method for calculating the stress-strain state of a robotic structure made of composite material under dynamic action. The bearing capacity of multilayer composite materials is affected by the location of the warp threads of the composite material. By changing the orientation of the layers, it is possible to change the bearing capacity of the composite material. In the present work, such a study was carried out for a robotic system made of a composite material under the action of a dynamic operational load. An eight-layer composite material with different layer orientations was considered. Carbon fiber was used as the basis. As a robotic system stand was considered, designed to simulate flight characteristics in laboratory conditions. The simulation of the stand was carried out. The bench was approximated by finite elements. The convergence of the results of the finite element model of the stand was checked by condensing the finite element mesh and comparison the results obtained. Robotic systems are equipped with elements that move the channels: bearings, gear rims, gearboxes, motors. In the present study they were replaced in the finite element model with a system of bar elements of identical stiffness. The design of the stand was a three-layer structure, consisting of external carrier layers of an eight-layer composite material and a filler layer between the carrier layers of lightweight material in the form of foam and used to absorb shear stresses and prevent the bearing layers from approaching. Calculation and analysis of the design of the stand for dynamic load is carried out, the stress-strain state of the stand is obtained for different arrangement of the layers of the composite material.