AlfaBuild

RAR RUS 3101-3101 Kalashnikov Izhevsk State Technical University Pushkarev Ivan Andreevich Natural frequencies of innovative building structures with several vibration sources The object of research is the dynamics of innovative building structures in the form of thermostructural panels. The panels are exposed to several vibration sources with unbalanced masses. The sources are established on the same basis. It is assumed that self-synchronization may occur when exposed to several vibration sources with unbalanced masses. Method. A design diagram has been drawn up for the location of several vibration sources in a building on one beam. The sources of vibration were rotors with unbalanced masses. The equations of motion of the rotors were compiled based on the Lagrange equations of the second kind. An analytical solution is found under the assumption that the angular velocities of the rotors are constant. The displacements of the system's center of mass from the equilibrium position are determined. The circular frequencies of natural transverse vibrations of a beam of constant cross-section are determined. Results. The results indicate that the values of the first natural frequency of the beam when it is rigidly fastened are close to the frequency of household engines with rotating parts with an unbalanced mass, and there is a danger of self-synchronization. It is shown that at specific attenuation coefficient values, the beam's displacement amplitude exceeds the permissible values. 10.57728/ALF.31.1 69 Beam Dynamic analysis Natural frequency Vibrations Damping coefficient Innovative building structures https://alfabuild.spbstu.ru/article/2024.31.1/ 3101.pdf

RAR RUS 3102-3102 0000-0002-7112-4778 Sokolov Nikolay Nikolaevich sokolov.nn@edu.spbstu.ru 0000-0003-3703-0222 Diakov Stanislav Fedorovich dyakov_sf@spbstu.ru 0000-0002-2742-1345 Ibragimov Timur Ravilevich timuribragimov.ra@gmail.com 0000-0002-6637-3059 Melekhin Egor Markovich Egor.melechin@yandex.ru 57205072984 0000-0002-5527-0345 Peter the Great St. Petersburg Polytechnic University Mohireva Arina Olegovna mohirevaarina@mail.ru

St. Petersburg, Russian Federation

An algorithm of automatic cross section assignment for the space truss bars The object of research is development of an algorithm that can be used as a tool in the design of space trusses made of round tubes. Method. At this stage the algorithm aims to work only with rolled round tubes according to Russian grades. In the first approximation the algorithm is divided into two components: reassignment of sections according to the selected assortment and unification to the required number of bars. At the end of the first stage, intermediate results can be uploaded to check how much the mass of the structure has increased. In addition, saving the intermediate results allows you not to restart the first stage if the initial data for the second stage has changed. Results. The algorithm which automates the assignment of sections according to a given assortment and optimized unification of section sizes to a given number of different rolled products and can be applied to any truss or space truss. For statically indeterminate rod systems where the longitudinal force is many times greater than the moment, this method can also be applied, but verification calculations will be required. 10.57728/ALF.31.2 69 Optimization algorithm Space truss Structural engineering Steel pipes https://alfabuild.spbstu.ru/article/2024.31.2/ 3102.pdf

RAR RUS 3103-3103 0000-0002-7112-4778 Sokolov Nikolay Nikolaevich sokolov.nn@edu.spbstu.ru 0000-0003-3703-0222 Diakov Stanislav Fedorovich dyakov_sf@spbstu.ru 0000-0002-2742-1345 Ibragimov Timur Ravilevich timuribragimov.ra@gmail.com 0000-0002-6637-3059 Melekhin Egor Markovich Egor.melechin@yandex.ru 57205072984 0000-0002-5527-0345 Peter the Great St. Petersburg Polytechnic University Mohireva Arina Olegovna mohirevaarina@mail.ru

St. Petersburg, Russian Federation

Designing a nonregular space trusses layout using additive technologies The object of research is a prototype algorithm that allows to create space trusses by setting only the initial data and controlling the result. Method. Is to develop an algorithm, which creates a space truss by using methods of layout optimization, then optimizes cross-sections of elements and prepares all data for verification calculation and describing characteristics of the design. Then, Using the data from the trial run of the algorithm, compare the results with traditional approaches to the design of spatial trusses. Results. An algorithm for the automated design of a space trusses with an optimal layout has been developed and it has been demonstrated on the example of a specific problem that such an approach will significantly reduce the material intensity of structures. However, all this is possible only with full automation of the design process and considering that all nodal connections are also generated automatically and produced additively using industrial printers. 10.57728/ALF.31.3 69 Optimization algorithm Space truss Structural engineering Steel pipes Additive manufacturing https://alfabuild.spbstu.ru/article/2024.31.3/ 3103.pdf

RAR RUS 3104-3104 0000-0002-6848-0974 Moscow Power Engineering Institute Luong Cong Luan luongcongluan96@gmail.com

Moscow, Russian Federation

H-9967-2013 16412815600 0000-0002-8588-3871 Moscow Power Engineering Institute Kirsanov Mikhail Nikolaevich mpei2004@yandex.ru

Moscow, Russian Federation

The first frequency and frequency safety area of a cantilever truss with an arbitrary number of panels The object of research is a planar model of a statically determinate truss system. Method. The rigidity and first natural frequency of oscillations of the truss are analyzed analytically. If the truss rods have the same cross-section, and the mass of the truss is evenly distributed among its nodes, then each mass has one degree of freedom, and the stiffness of the rods is the same. Using induction, analytical expressions for the deflection are found. The formula for the dependence of the main (first) natural frequency of oscillations of the truss on the number of panels is derived by the Dunkerley method. Based on the results of calculating deflections in a series of similar trusses with different numbers of panels, the expected dependence of deflections on the load, elastic properties of the rods and the number of panels was obtained. The solution of the system of linear equations that determine the force in the rods and any transformations are performed in the Maple computer mathematics package. Using the Maxwell-Mohr formula, the stiffness matrix of the structure can be determined. Results. The first natural frequency of the truss obtained by the analytical method is compared with the results of the numerical method. The frequency spectrum of the truss was analyzed, and conclusions were drawn about the dependence on the size of the panels. In the combined frequency spectrum of a family of regular trusses, a region of unattainable frequencies is identified. 10.57728/ALF.31.4 69 Truss First natural frequency Dunkerley method Maple Analytical solution Frequency safety area https://alfabuild.spbstu.ru/article/2024.31.4/ 3104.pdf

REV RUS 3105-3105 0000-0002-3142-6018 Kirsanova Tatiana Aleksandrovna 89094001052@mail.ru 0000-0002-2596-0855 Chistyakov Vladimir Anatolyevich R-7951-2019 57197681036 0000-0002-7521-5079 University of Zanjan Rahmani Hamid hrahmani@znu.ac.ir

Zanjan, Iran

0000-0003-0160-8520 Vdovchenkov Evgeny Viktorovich 0000-0002-9174-2338 Aramova Olga Yurievna 0000-0003-0088-2990 Alliluyeva Ekaterina Vladislavovna Overview of developments in the field of adobe bricks Reactions and biological processes in the adobe mixture represent the integration of biological and technological aspects, which opens new prospects for research in the field of biomineralization of building materials. The object of research is an adobe brick, in which various biological and molecular interactions of its constituent components occur. Method. A detailed description of the methodology of the literature search research has been carried out and current world research on the use of adobe bricks in construction has been systematized. Results. A review of studies on the properties of moisture capacity, compressive strength, thermal insulation properties and durability properties of adobe has been conducted. The influence of chemical processes on its properties is considered, problems and limitations associated with the use of adobe bricks are identified, based on which conclusions are drawn and recommendations for further research are proposed. The role of biological processes in adobe brick construction technology is considered. 10.57728/ALF.31.5 69 Adobe Adobe brick Brick Clay Manure Molecular interaction https://alfabuild.spbstu.ru/article/2024.31.5/ 3105.pdf

RAR RUS 3106-3106 0000-0002-4515-6880 Liseitsev Yury Leonidovich yury.liseitsev@mail.ru N-6730-2017 57199850188 0000-0002-2279-1240 Far Eastern Federal University Fediuk Roman Sergeevich roman44@yandex.ru

Vladivostok, Russian Federation

0000-0002-7395-6557 Nagruzova Lyubov Petrovna L_nag@bk.ru Road surfaces made of nanomodified fiber-reinforced concrete The object of research is road surfaces made of nanomodified fiber concrete. This work aims to develop a scientifically sound technological solution aimed at improving road surfaces made of nanomodified fiber concrete, as well as a comprehensive study of their characteristics. Method. The entire range of physical and mechanical properties and performance characteristics of modified composite binders and basalt fiber concrete based on it was studied. Results. Modified composite binders have been developed, which are an effective basis for obtaining fiber concrete, with an elastic-viscous microstructure (elastic modulus 40.3 GPa, Poisson's ratio 0.20) and high performance characteristics (grades: G1 (abrasion resistance), W18 (water resistance), F2300 (frost resistance), T15-T115 (heat resistance for classes according to maximum permissible application temperature I9-I11)), which allows the use of composites for highways). 10.57728/ALF.31.6 69 Concrete Composite Astringent Superplasticizer Road Nanomodification Strength https://alfabuild.spbstu.ru/article/2024.31.6/ 3106.pdf