Актуальность темы исследования. Процессы электродуговой сварки и наплавки автоматическим или механизированным оборудованием одни из наиболее востребованных технологий постоянно совершенствуются, в том числе и за одним из основных направлений – применение импульсных воздействий. Перспективным является применение импульсной подачи электродной проволоки, а в последнее время подачи с управляемыми характеристиками и дозированной подачи. Широкое применение оборудования с импульсными алгоритмами движения электродной проволоки несколько сдерживается, в том числе из-за недостатка исследований по технико-технологическим возможностям сварки–наплавки с импульсной подачей электродной проволоки. Постановка проблемы. С целью обоснованного выбора способа импульсной подачи электродной проволоки и эффективного его применения при сварке и наплавке, в том числе сложных для дугового процесса дуплексных сталей, необходима комплексная оценка влияния импульсов движения проволоки с различными параметрами на формирование металла шва, наплавленного слоя, а также их структуру и другие характеристики сварочного процесса. Анализ последних исследований и публикаций. Исследования, касающиеся влияния импульсной подачи электродной проволоки на технико-технологические результаты электродуговой сварки и наплавки механизированным оборудованием, проводятся постоянно, что частично отражено в отечественной и зарубежной технической литературе, однако, как правило, они не носят комплексного характера и зачастую не подтверждены доказательными экспериментальными исследованиями с использованием современной техники эксперимента. Всё это не позволяет оценить в полной мере возможности импульсной подачи электродной проволоки и расширить применение соответствующего оборудования. Выделение неисследованных частей общей проблемы. До настоящего времени остаются не до конца исследованными вопросы, связанные со структурой металла шва или наплавленного слоя, выполненных с импульсной подачей электродной проволоки в управляемом режиме. При этом следует детально изучить колебания сварочной ванны, распределение температур в ванне и околошовной зоне и др. Особое внимание следует уделить новому способу сварки-наплавки с дозированной подачей. Постановка задачи. На основе комплексных экспериментальных исследований необходимо рассмотреть и проанализировать ряд основных возможностей применения механизмов управляемой импульсной подачи электродной проволоки, дозированной подачи с определением их влияния на свойства металла шва и наплавленного валика. Экспериментальные исследования провести с выявлением колебаний ванны, распределений тепла, сравнительным анализом микроструктур, замеров кристаллитов и др. Изложение основного материала. Представлены и проанализированы результаты экспериментальных исследований, касающиеся результатов, получаемых при сварке-наплавке с управляемой и дозированной подачей электрод-ной проволоки. Эти результаты относятся к формированию сварного шва, его структуре, выявлению её особенностей. При этом изучены явления колебаний ванны, формирование теплового поля, микроструктуры сечений наплавленных валиков, определены размеры кристаллитов. Полученные данные свидетельствуют о факте значи-тельного положительного влияния на формирование сварного шва и наплавленного слоя, их структуру и возможности управления ими за счёт изменения параметров импульсов подачи электродной проволоки, что делает возможным расширение применения рассмотренных способов сварки и наплавки. Выводы в соответствии со статьёй. Ряд исследований, которые направлены на выявление эффективности процессов сварки и наплавки при применении управляемой импульсной подачи электродной проволоки относятся к физико-механическим и другим свойствам сварных соединений и наплавленных слоёв и показывают существенные преимущества в сравнении с конвенциальной подачей, обеспечивая повышение качества металла, в том числе и за счёт дробления кристаллитов и снижения тепловложений. Среди ряда способов обеспечения импульсной подачи дозированная подача, с обратными связями по параметрам дугового процесса, наиболее эффективна. Эффективность применения процессов сварки и наплавки может быть использована при сварке плохо свариваемых сталей и сплавов алюминия. Это, в частности, касается сварки дуплексных сталей, некоторых сплавов алюминия, тонколистовых конструкций. Следует рекомендовать всё более широко применять механизированное и автоматическое оборудование в технологической практике при создании и ремонте самых разнообразных конструкций.

The Institute has contributed considerably to the development of the world science, gained a lot of important results that constituted a basis of new methods and approaches of modern mechanics.Since its early years the Institute has intensively studied the fatigue mechanisms of bridge and boiler steel, the strength of bridge elements and machine parts depending on mechanical factors and processing conditions, solved problems of the dynamic strength of military structures, studied the stability of engineering structures within and beyond elasticity, developed the traditional fields of the theory of elasticity and thermoelasticity, theory of shells, stress concentrations, fatigue, strength, and plasticity of materials and structural elements.Scientists of the Institute have made it possible to develop new scientific fields, such as the mechanics of composites of deterministic and stochastic structure, the three-dimension theory of stability and wave dynamics of deformable bodies, the theory of coupled mechanical and physical fields in structural elements, numerical methods of the theory of shells, the analytical mechanics of polyaggregate systems, the nonlinear theory of vibrations of solids and bodies with fluid.The creation of the world-famous Krylov-Bogolyubov-Mytropolsky school of nonlinear vibrations was a great achievement which determined the further development of mechanics.The results obtained at the Institute have been applied in space, aircraft, ship-building, and other industries.Today, the Institute continues research in the fields of the mechanics of composites and inhomogeneous media, shell systems, fracture and fatigue, dynamics and stability of mechanical systems.Your highly professional, hard-working, and talented team is working tirelessly to enhance the economic and industrial development of our country.

years since the S. P. Timoshenko Institute of Mechanics was founded.The Institute has always played a special role in the development of Ukrainian and world mechanics and formation of areas of research.The creation of the world-famous school of nonlinear mechanics brightly illustrates the aforesaid.The world scientific community is well aware of the achievements of the Institute in developing new standards of strength, determining the physical and mechanic properties of rock, developing a nondestructive method for the determination of the mechanical properties of wood, studying the strength of bridge elements and developing their failure criteria, formulating the statistical theory of fatigue fracture, solving problems of dynamic strength of military structures.The Institute has developed the theory and methods of designing plates and shells of revolution, studied the energy dissipation in turbine blades, discovered the new phenomenon of absorption fatigue of metals, suggested a method for mechanical tests of hard and fragile steels at different temperatures, developed a new method of evaluating the wear resistance of steels from the physical and mechanical characteristics of the surface layer.The Institute developed new research areas related to composites, thermoplasticity, numerical methods of the theory of shells, the nonlinear theory of vibrations of solids, etc.The findings in these areas are applied in many industries, and engineering practice of leading research and development institutions, and design offices.Today, the Institute is studying a wide range of aspects in elasticity and thermoplasticity, theory of shells, stress concentration, fatigue, strength, and plasticity of materials and structural elements, collaborating with such leading state-owned enterprises, including and Pivdenne Design Office, Antonov Design Office, and others.The scientists of the S. P. Timoshenko Institute of Mechanics by their selfless work represent Ukraine in the avant-garde of the world science and technology*.I am sure that the mechanicians of the Academy will overcome decently all difficulties we now face, and in the future will gain a lot of significant results to enhance the economy and strengthen the defense potential of our country.I heartedly wish you all good health, creative findings for the sake of our people, our Ukraine.

The paper deals with the issues of an application of acoustic emission (AE) method of continuous monitoring, with prediction of breaking load. System of continuous AE monitoring of pipelines of hot industrial steam overheating in power unit #1 at Kiev TPP-6 has been developed and put into trial operation. Preliminary the acoustic properties of steam pipeline materials were studied; high-temperature AE studies of steam pipeline material were conducted. Developed procedure allows determination of structure material breaking load, based on AE data, under actual operating conditions of the structure at any moment of time, irrespective of operating time volume or temperature variations. Breaking load predicted by continuous AE monitoring system is determined with accuracy sufficient for practical purposes. To ensure the time margin when taking the decision on the monitored facility state, safety factors were established for the predicted breaking load, which are automatically determined by the monitoring system, depending on the degree of danger of the destructive processes developing in the material. Monitoring schematic and features of practical application of monitoring system are presented. Applied procedure and technology allow determination of the coordinates of monitored facility section with minimum breaking load magnitude. Remote access allows performance of author’s supervision of system operation through the Internet.

A new design of electron beam gun for welding in open space has been developed. The gun design is based on the application of triode emission system with improved quality of electron beam formation. This provides increased specific power of the beam and, as a result, the high capability to increase the penetration depth of welded joints. To reduce the dimensions of the gun and increase its service reliability, the high-voltage insulation has been provided applying metal-ceramic heat-resistant welded-brazed vacuum-tight components. The original technologies for their manufacture have been developed. The performed tests of the new gun design have proved the possibility of its application under open space conditions.

REmARkAbLE JUbILEEof low temperatures was carried out.For the first time in Ukraine the systems of diagnostics of welded structures, to which the high requirements of safety are specified, were developed.Borys E. Paton supervised the investigations with use of the electroslag process for quality improvement of metals and alloys, which resulted in appearance of the radically new direction in the metallurgy: electroslag remelting and casting.The technologies of the electroslag remelting, developed at the Institute, found the wide application and were worldly recognized.Borys E. Paton is the scientist-innovator.The technologies, developed under his supervision, are successfully operating on the Earth, under the water and in space.The E.O.Paton Electric Welding Institute of the National Academy of Sciences of Ukraine, headed by B.E. Paton, is the powerful scientific institution, where many generations of scientists-welders were born and formed.Borys Paton brought up hundreds of talented scientists and engineers.The thorough understanding of science role in the society, its aims and tasks, high international authority of the scientist, devotion to the science, inexhaustible energy and high moral qualities, active social-political activity, experience in management of the large scientific staff became a decisive arguments in election of Borys E. Paton on the post of the President of the Academy of Sciences of the Ukrainian SSR in 1962 (now the National Academy of Sciences of Ukraine).Since that time he is heading this leading scientific organization in Ukraine over 56 years.His talent of the eminent organizer was greatly displayed on the responsible post of the President of the National Academy of Sciences of Ukraine.With his participation the new structure of the Academy of Sciences and its new status were worked out, directed to the most rational application of scientific efforts and means, their concentration in the solution of the most important fundamental and applied scientific problems, which have the great importance for the country economy, dozens of new institutes and organizations were founded, which developed and intensified investigations in the most important scientific directions.The distinguished abilities of B.E. Paton as a leader, scientist and organizer were revealed in a dramatic Chernobyl tragedy.The associates of many institutes of the Academy of Sciences, its Presidium were included from the first days into the work for liquidation of the catastrophe consequences.Borys E. Paton made a lot of efforts for the development of the international scientific cooperation of Ukraine, the implementation of national science in the European and world scientific community.By his initiative the International Association of Academies of Sciences was organized in 1993, which united the National Academies of 15 countries of Europe and Asia.During almost 25 years Borys E. Paton was permanent President of this Association.Borys E. Paton is the well-known state and public figure.Many years he was elected to the structure of government bodies, he was and is now a leader and member of different committees and commissions.By occupying high posts, he is working fruitfully with a high sense of personal responsibility to the state, people, own conscience.

In the Ye. O. Paton Electric Welding Institute a new generation of electron-beam hand tools was created for welding and related technologies. This equipment is used during assembling and repair-restoration work on manned spacecrafts in outer space. It is possible to use the tools not only in a manual but also in automatic mode using robotic devices. The developed equipment and technologies can also be applied during the operations related to the exploration of the Moon and missions to Mars. The new generation tools were used in works on optimization of welding technology for aluminium and titanium alloys as well as stainless steels. The results obtained in investigations of welded joints confirmed the higher efficiency and reliability of the developed equipment.

Shape-memory alloys changing part configuration at heating, as well as preserving their elasticity at up to 8-10 % deformation, are becoming ever wider applied in industrial products and apparatuses as thermally-activated elements.Commercial application of alloys of Cu-Al system instead of well-studied alloy of Ti-Ni system (nitinol) allows lowering product cost and expanding the application area up to high temperatures (about 400 °C).Widening the range of products with elements from shape-memory alloys requires studying the possibility of joining metals of this system with structural metals, in particular, with stud-type fasteners.Proceeding from available experience, joints of studs from low-carbon steel of St.3 grade and 12Kh18N9T stainless steel, as well as L63 brass and AMg3 aluminium alloy produced by the methods of arc-contact welding by a capacitor discharge and by DC pulse were studied.Good results were obtained at capacitor welding of studs from the above materials, except for AMg3.The latter is attributable to greater mismatch of thermophysical properties of the metals joined.In DC welding, strong joints were produced only with studs from St.3 steel, because of greater time of welding.It is shown that pulsed welding methods enable preserving functional properties of parts from shape-memory alloys.Inhomogeneity of butt metal structure was found in dissimilar metal welding, which is attributable to short-time existence of the melt (incomplete mixing) and heterogeneity and non-simultaneity of joint cluster solidification.A positive consequence of that is absence of brittle intermetallics of FeAl 3 type in the butt and preservation of ductility at deformation of joints with steel studs.5 Ref., 1 Table, 9 Figures. K e y w o r d s : shape-

практика эксплуатации машин, конструкций и сооружений все настойчивее требует создания методов и средств, с помощью которых можно было бы определять на основании имеющихся данных их функциональные возможности в любой момент времени, как в прошлом, так и в настоящем, а также прогнозировать на базе этих данных их состояние и поведение в будущем.Как правило, расчетным путем трудно оценить, как именно и при каких значениях параметров, характеризующих работоспособность конструкции, начнется разрушение

Cu—Al based shape-memory alloys (SMA) are an attractive replacement for expensive SMA of Ti—Ni system in fasteners, thermal automatic device activators, and superelastic elements of instrumentation. Therefore, the problem of joining the latter in different combinations with similar material and other structural metals has become urgent. The main requirement to such joints, in addition to strength, is preservation of functional characteristics, namely temperature range of shape restoration at thermoelastic martensite transformation. Weldability of Cu—Al alloys in the form of 0.05 mm thick foil, 0.3 mm thick strip and 1 mm diameter wire by spot and butt capacitor-type welding was studied, and it was shown that at pulsed welding heating the functional characteristics in the welding area are preserved in joints with rupture strength, corresponding to the respective base metal strength. Metallographic examination showed recrystallization of the initial coarse-crystalline metal in welding heating zone with formation of fine-crystalline structure, both in the solid-state joints and around the cast nugget in spot welding of 0.3 mm strip. Sound butt joints of SMA and copper wire were produced. 5 Ref., 1 Table, 10 Figures.

The brief review of design solutions for existing transformable-volume structures (TVS) is given and main approaches are formulated for optimizing the metal transformable shell structures, allowing widening the sphere of their application in space engineering. Characterized are the methods, used for theoretical description of process of change in TVS shape, and also geometric parameters and properties of structural materials of thin shells allowing realization of their volume deforming at the maximum approach to the selected theoretical model.Technological aspects are described which are typical of the process of multi-sectional conical TVS design as applied to the conditions of its service under the effect of space environment factors (SEF). (C) 2015 IAA. Published by Elsevier Ltd. All rights reserved.