scholarly journals Изгиб и растяжение судовых композитных элементов

Author(s):  
S.I. Koryagin ◽  
O.V. Sharkov ◽  
N.L. Velikanov

Полимерные покрытия давно и прочно завоевали свое место при изготовлении и ремонте судовых конструкций. Одной из причин, сдерживающих их более широкое применение, является отсутствие расчетных зависимостей, позволяющих рассчитать прочностные свойства композитных элементов. Для построения этих зависимостей необходимы дальнейшие экспериментальные исследования, их анализ и обобщение. В работе представлены результаты исследований прочностных свойств металлических конструкций судов с армированным полимерным покрытием при растяжении и изгибе. Экспериментально было установлено, что разрушение покрытия происходило при линейных деформациях основы на границе адгезионного слоя. При загрузке образца сосредоточенной силой определены усилия, при которых произойдет механическое разрушение композиционного образца по адгезионному слою. Построены зависимости разрушающей нагрузки от соотношения толщин основы и покрытия при растяжении и изгибе, проведено сравнение с экспериментальными результатами.Polymer coatings have long and firmly won their place in the manufacture and repair of ship structures. One of the reasons restraining their wider application is the lack of computational dependencies that allow to calculate the strength properties of composite elements. Further experimental studies, analysis and generalization are needed to construct these dependencies. The paper presents the results of studies of strength properties of metal structures of ships with reinforced polymer coating under tension and bending. It was found experimentally that the destruction of the coating occurred during linear deformations of the substrate at the boundary of the adhesive layer. When loading a sample with a concentrated force, the forces at which the mechanical destruction of the composite sample along the adhesive layer will occur are determined. The dependences of the breaking load on the ratio of the thickness of the substrate and the coating under tension and bending are constructed, a comparison with the experimental results is carried out.

2019 ◽  
Vol 968 ◽  
pp. 68-75
Author(s):  
Valeriy Vyrovoy ◽  
Viacheslav Bachynckyi ◽  
Nadia Antoniuk

The paper presents the development of optimum structures and the production of polymeric coatings technology which can absorb aggressive substances. The studies of coatings penetrating into the film are presented due to the organization of their capillary-cellular structure by introducing special fillers. A new approach to solve the problem of protecting the environment, people, buildings and structures from the effects of aggressive substances has been proposed. The essence of the method consists in the preventive deposition on the surfaces of construction objects of porous coatings that can irreversibly absorb aggressive substances. Based on theoretical and experimental studies, porous coatings have been developed that are capable of accumulating in their volume aggressive substances, as well as certain principles of providing the coating with the necessary capillary-porous structure. The mechanism of creating a capillary-cellular structure of a polymer coating based on nitrocellulose are substantiated.


Author(s):  
С.И. Корягин ◽  
О.В. Шарков ◽  
Н.Л. Великанов

Применение полимерных покрытий для ремонта корпусных конструкций выдвигает как актуальную задачу определения прочностных характеристик конструкций с покрытиями. Наличие отверстий, сквозной коррозии, являющихся концентраторами напряжений, делает эти места наиболее опасными, с точки зрения потери прочности, герметичности. Чаще всего разрушение происходит по адгезионному слою. Представлена математическая модель, учитывающая сосредоточенные усилия на концах адгезионного слоя композиционной конструкции типа «металл-покрытие». Проведены расчеты нормальных и касательных напряжений. Наибольшие значения напряжений в полимерном покрытии получены на кромке отверстия в слое металла. В результате анализа установлено, что увеличение перекрытия полимерным покрытием контура отверстия и удаленность от контура отверстия приводят к существенному уменьшению величин напряжений. Разработанная математическая модель и алгоритм вычислений позволяют расчетным путем определить напряженно-деформированное состояние металлической конструкции с отверстием и полимерным покрытием. The use of polymer coatings for the repair of hull structures puts forward as an urgent task to determine the strength characteristics of structures with coatings. The presence of holes, through corrosion, which are stress concentrators, makes these places the most dangerous, in terms of loss of strength, tightness. Most often, the destruction occurs along the adhesive layer. A mathematical model is presented that takes into account the concentrated forces at the ends of the adhesive layer of a composite structure of the "metal-coating" type. Calculations of normal and tangential stresses are performed. The highest stress values in the polymer coating are obtained at the edge of the hole in the metal layer. As a result of the analysis, it was found that an increase in the overlap of the polymer coating of the hole contour and the distance from the hole contour lead to a significant decrease in stress values. The developed mathematical model and calculation algorithm allow calculating the stress-strain state of a metal structure with a hole and a polymer coating.


2021 ◽  
Vol 21 (3) ◽  
pp. 63-74
Author(s):  
Andrzej Kubit ◽  
Tomáš Katrňák ◽  
Tomasz Pytlowany

Abstract The article presents the results of experimental studies determining the influence of the type of adhesive on the static strength properties of the Glass Fiber Reinforced Polymer (GFRP) composite joint determined on the basis of the T-peel test. As part of the static tests on peeling joints, a comparison of peak load and stiffness for individual joints was made. The fracture surfaces were also analyzed, showing various failure mechanisms. It was shown that the variant of joints made with the Enguard BP72A polyester adhesive was characterized by the highest strength properties with a mean peak load of 836.73 N.


Author(s):  
С.И. Корягин ◽  
О.В. Шарков ◽  
Н.Л. Великанов

Эксплуатация корпусных конструкций современных морских судов проходит в различных частях Мирового океана. Температура окружающей среды может изменяться в широких пределов от резко отрицательных до высоких температур тропических районов. Наличие полимерных покрытий на металлических конструкциях способствует улучшению их работы. Работоспособность полимерных покрытий требует проверки при изменении температуры, влажности воздуха. Проверка может быть проведена в условиях лабораторного или натурного экспериментов. В статье описаны экспериментальные исследования адгезионной прочности полимерных покрытий в лабораторных условиях. Установлены зависимости напряжений от изменений различных показателей окружающей среды. Показано, что для исследуемых полимерных покрытий изменение этих показателей мало влияет на адгезионную прочность покрытий. Проведенные исследования будут способствовать разработке технологий нанесения полимерных покрытий, устойчивых к изменениям климатических факторов. The operation of the hull structures of modern marine vessels takes place in various parts of the World Ocean. The ambient temperature can vary widely from sharply negative to high temperatures in tropical areas. The presence of polymer coatings on metal structures helps to improve their performance. The performance of polymer coatings requires checking when changing the temperature and humidity of the air. The test can be carried out in the conditions of laboratory or field experiments. The article describes experimental studies of the adhesive strength of polymer coatings under laboratory conditions. The dependences of stresses on changes in various environmental parameters are established. It is shown that for the studied polymer coatings, the change in these parameters has little effect on the adhesive strength of the coatings. The conducted research will contribute to the development of technologies for applying polymer coatings that are resistant to changes in climatic factors.


The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.


2020 ◽  
pp. 68-77
Author(s):  
O.N. CHERNYKH ◽  
◽  
A.V. RBURLACHENKO

Recommendations are presented for solving issues that arise in the design and operation of tubular transport crossings of corrugated metal structures through spawning streams while ensuring the safety and natural reproduction of fish stocks. There are discussed the results of experimental studies of culverts made of metal corrugated pipes with a normal and spiral shape of corrugation the bottom of which is buried and filled with suitable granular material to the level of the natural channel of a small watercourse. It is established that when 10% of the area of the corrugated pipe is occupied by stone filling, its throughput is reduced by about 10-12%. Based on the review of the existing literature and the results of laboratory experiments, data is provided to estimate the values of the roughness coefficients of the composite cross-section of a single-point junction and directions for future research on culvert reclamation are outlined. Studying of the structure of the velocity distribution in culverts can lead to the improved conditions for fish passage without installing special structural elements in the transit path of the fish passage structure.


2015 ◽  
Vol 4 (9) ◽  
pp. 974-978 ◽  
Author(s):  
Shan Wang ◽  
Haolong Li ◽  
Dan Li ◽  
Tianyang Xu ◽  
Shilin Zhang ◽  
...  

2019 ◽  
Vol 53 (6) ◽  
pp. 426-432 ◽  
Author(s):  
Amitabh Madhukumar Chopra

Abstract Lubricious polymer coatings are increasingly used on intravascular devices to facilitate easier access and navigation through tortuous blood vessels. Recent reports highlight the separation and downstream embolism of polymer particles affecting the vasculature and various organs. The Food and Drug Administration (FDA) acknowledges polymer coating embolism as an iatrogenic complication of intravascular devices and continues to close gaps in standards related to coating integrity. The Association for the Advancement of Medical Instrumentation established particulate testing as an industry standard for evaluating coating integrity of intravascular devices. The FDA recognizes this standard; however, challenges exist in setting particulate limits that may compromise device function without sufficient clinical data. The microscopic nature of polymer emboli not visible with available imaging modalities has impacted reporting. This has also resulted in a reduced number of manufacturer-driven product development projects related to coating integrity. On the other hand, recent procedural trends have supported the innovation of coated devices with expanded indications, requiring particulate evaluations and release limits. This article proposes a methodology to set particulate limits for intravascular devices given existing clinical, regulatory, and manufacturing challenges. The approach with standardization requirements enables characterization, comparison, and evaluation of lubricious coatings from various manufacturers. It incorporates a step-by-step procedure that adds scrutiny to the application of coatings while ensuring device function is not impacted. Together with particulate assessments, clinicopathologic and animal studies permit an understanding of particulate ranges from commercially available devices and setting of particulate limits for new device evaluations.


Author(s):  
D.J. Varacalle ◽  
K.W. Couch ◽  
V.S. Budinger

Abstract Experimental studies of the subsonic combustion process have been conducted in order to determine the quality and economics of polyester, epoxy, urethane, and hybrid polyester-epoxy coatings. Thermally sprayed polymer coatings are of interest to several industries for anti-corrosion applications, including the infrastructural, chemical, automotive, and aircraft industries. Classical experiments were conducted, from which a substantial range of thermal processing conditions and their effect on the resultant coating were obtained. The coatings were characterized and evaluated by a number of techniques, including Knoop microhardness tests, optical metallography, image analysis, and bond strength. Characterization of the coatings yielded thickness, bond strength, hardness, and porosity.


2020 ◽  
pp. 451-457
Author(s):  
Aleksandr Yur'yevich Vititnev ◽  
Yuriy Davydovich Alashkevich ◽  
Natal'ya Geral'dovna Chistova ◽  
Roman Aleksandrovich Marchenko ◽  
Venera Nurullovna Matygullina

This paper presents the results of experimental studies of the physical and mechanical properties of wood-fiber boards of the wet production method when regulating the design and technological parameters of the grinding process. This allowed us to determine the influence of the working clearance between the grinding discs and the concentration of fibre mass with the subject to of quality change wood fiber after defibrator using the developed construction of the disc fibrillation action on the physico-mechanical properties of boards. As a result of the experiment, regression models were obtained that adequately describe the studied grinding process and allow predicting the values of physical and mechanical properties of the finished product depending on the established  parameters process. A comparative analysis of the size and quality characteristics of the fiber semi-finished product and its fractional composition when using a developed construction the disc of refiner fibrillation action and a traditional design used in industry is carried out. The preferential efficiency of the grinding process under the fibrillating effect the disc of refiner in comparison with the traditional construction disc of refiner is established. As a result, there is a significant improvement in the quality indicators of the fiber semi-finished product and its composition due to the formation and predominance in the total mass of long and thin, respectively, flexible fibrillated fibers with high tile-forming properties, which allows to increase the strength properties of the product (by 20–25%), without using binding resins.


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