Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra最新文献

{"title":"Dissipative properties of three-layered composite structures. 3. Objects of study","authors":"B. Yartsev, V. Ryabov, L. Parshina","doi":"10.24937/2542-2324-2022-2-400-51-58","DOIUrl":"https://doi.org/10.24937/2542-2324-2022-2-400-51-58","url":null,"abstract":"Object and purpose of research. The object of research is a sandwich plate formed by two rigid anisotropic layers and a soft isotropic layer of viscoelastic polymer in the middle. Each rigid layer is an anisotropic structure formed by a finite number of arbitrary oriented orthotropic viscoelastic layers of composites. The purpose of work is to choose the objects of research demonstrating main features of parameters of natural decaying oscillation of sandwich plates. Materials and methods. Qualitative analysis of differential equations describing decaying oscillations of anisotropic plates of various compositions and reinforcement structures. Main results. The main objects of research are two special reinforcement structures of rigid layers made up of unidirectional CFRP layers: symmetric and asymmetric structures. The symmetric reinforcement structure of rigid layers is formed by an assembly of unidirectional CFRP layers with the same orientation relative to the global axes of these layers. In the asymmetric structures the unidirectional CFRP layers are oriented in the opposite directions with respect to the global axes of the rigid layers. Results of numerical modeling of quasi-homogeneous monocline plate dynamic response are given. It is shown that coupled oscillations of the symmetric sandwich plate are described by two systems of differential equations similar to the equation systems that describe decaying oscillations of quasi-homogeneous monocline plate. While the coupled oscillations of the asymmetric sandwich plate are described by two systems of differential equations coinciding with the systems of differential equations describing decaying oscillations of globally orthotropic sandwich plate. Conclusion. Further to this paper, discussion of numerical experiments on chosen objects of research will be given.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41889976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Active absorption of acoustic pulse in waveguide","authors":"Y. Popov","doi":"10.24937/2542-2324-2022-2-400-158-168","DOIUrl":"https://doi.org/10.24937/2542-2324-2022-2-400-158-168","url":null,"abstract":"Object and purpose of research. A numerical model is taken as example to consider an active method of absorption for a short acoustic signal from reflecting boundary. Analysis is carried out on a model of virtual waveguide with rigid walls where the pulse with tonal content at one end and active absorption of the same at the other end is simulated. The purpose of studies is to assess the achievable method efficiency using a specific problem of signal absorption. Materials and methods. Signal propagation is estimated by finite element method using numerical model. The numerical calculations were verified by known analytical solutions according to the theory of wave propagation in waveguides. Main results. A numerical model is used as example to highlight the key tasks which have to be solved in the design of active signal absorption tools. Detailed consideration is given to the constraints of the waveguide model and acoustic signal to achieve the 9 dB efficiency obtained based on study results. Conclusion. The specific problem is taken to show that it is practically impossible to achieve full absorption of a short signal without reflection using only active methods. Conditions and ways of their implementation are identified without which it is impossible to achieve any significant effect by active absorption method.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42567015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Solution to the problem of minimum distance detection of various objects in shallow water depth","authors":"А.А. Gadzhiev, R. Eminov, K. Asadov","doi":"10.24937/2542-2324-2022-2-400-147-152","DOIUrl":"https://doi.org/10.24937/2542-2324-2022-2-400-147-152","url":null,"abstract":"Object and purpose of research. The object of research is arrangement of various items on the bottom of water bodies. The purpose of research is achieving maximum invisibility for such items. Anticipated search or accidental detection of bottom objects can be carried out by the bathymetric method, i.e. assessment of water column over such objects. Materials and methods. It is expected that low flying UAVs (unmanned aerial vehicles) equipped with bathymetric laser emitter are used for detection of underwater objects. With consideration of some simplifications, optimization is carried out for the operation of bathymetric laser detector of objects located on the sea bed. The task of detecting an underwater object is considered to be solved when the difference between the signals reflected from the sea bed and underwater object is reliably recorded. Minimum external detectability is achieved at minimum of the said difference. Main results. An objective functional is obtained to characterize the total signal from multiple underwater objects. As a result of performed optimization, the condition is determined at which the minimum of the objective functional is achieved. According to the obtained result, the total signal reflected from an underwater object reaches its minimum if the height of underwater objects and their reflection coefficient vary paraphase, i.e. the growth of one is accompanied with the reduction of the other. Conclusion. A method for minimum detectability of objects stacked on the sea bed is suggested and validated. Practical procedures of storing various objects on the sea bed are defined, which ensures their invisibility for the bathymetric laser detector onboard the low-flying UAV.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43773952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modification of containership hulls at speeds reduced for cutting down greenhouse gases","authors":"А.V. Sverchkov, M. Galushina, D. Vastarouchas, P. Politi","doi":"10.24937/2542-2324-2022-2-400-59-66","DOIUrl":"https://doi.org/10.24937/2542-2324-2022-2-400-59-66","url":null,"abstract":"Object and purpose of research. The objects of study are two containerships of 8100 and 8500 TEU capacities operated by Danaos Shipping Co. Ltd, Greece. The purpose is to experimentally verify alteration of bow shapes in the containerships designed to reduce hydrodynamic resistance at a lower operation speed, as well as to examine the impact of these alterations on energy efficiency design index (EEDI). Materials and methods. Experimental data from model tests were obtained in a deep-water test tank of Krylov State Research Centre. Main results. Based on the research studies the shaft power was determined versus the containership speed for the hulls with the original and modified bow shapes. Conclusion. Switchover to lower speeds combined with optimization and modernization of bow shapes will bring a possible reduction of shaft power and, accordingly, less fuel consumption and carbon dioxide emissions by about 40 %.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48773771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LNG bunkering tankers in marine ports: validation of demand in numbers","authors":"М.V. Vlasiev, G. Demeshko","doi":"10.24937/2542-2324-2022-2-400-89-98","DOIUrl":"https://doi.org/10.24937/2542-2324-2022-2-400-89-98","url":null,"abstract":"Object and purpose of research. The paper considers specialist vessels for re-fueling gas-engined ships, so-called LNG bunkering tankers (LNG bunkering ship as per the Russian Maritime Register of Shipping). The purpose is to formulate recommendations regarding the bunkering tanker fleet configuration for a marine port taking into consideration their functioning model and projected demand for natural gas motor fuel. Materials and methods. Operational experience of the ship type under consideration as well as the performance factors have been generalized and analyzed. Statistics of bunkering companies operating on the St. Petersburg port market have been collected and systematized enabling us to give recommendations for the projected fuel demand. Main results. Operational characteristics of bunkering tankers in the port bunkering infrastructure have been generalized. An approach is suggested for justifying the required number of LNG re-fueling tankers based on the game theory. The main factors defining the volumes of LNG fuel required in port are highlighted. A case study is given for validation of the bunkering tanker demand in numbers for the port of St. Petersburg. Conclusion. Bunkering tankers are a key link in the bunkering infrastructure of any harbor. LNG tankers are growing in numbers every year, which is related to more stringent requirements for environment pollution and reduced discharges from vessels in operation. This study enables justification of bunkering tanker numbers early in the design of a port bunkering infrastructure.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46240630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tests, checks and diagnostics of ship medium voltage transformers","authors":"I. Kalinin, О. Savchenko, М.Yu. Khmel","doi":"10.24937/2542-2324-2022-2-400-103-115","DOIUrl":"https://doi.org/10.24937/2542-2324-2022-2-400-103-115","url":null,"abstract":"Object and purpose of research. The study deals with the diagnostic Issues of ship MV transformers from factory acceptance tests to harbor trials. The purpose is to analyse the requirements and advanced diagnostic tools for status monitoring of ship power transformers, as well as to overview the Issues of electrodynamic withstand checks on transformers. Materials and methods. Stages (operations) are considered that ship power transformers undergo from the stage of factory acceptance tests to harbor trials. Requirements of ship transformers are analyzed. Foreign and Russian tools to check and measure power transformer parameters in industry as well as requirements for electrodynamic withstand testing are compared. Main results. It is shown that in view of high operational risks associated with accidents and failures of onboard transformers it is not enough to check transformer characteristics after transportation or storage (prior to onboard installation) for ensuring their high reliability. Functional analysis of foreign and Russian diagnostic instruments is presented, and vectors for improvement of the Russian tools are defined for the interest of shipbuilding industry. It is shown that the electric withstand tests are particularly important when new designs and technologies are used where reliable verification is impossible neither through calculations nor through modeling, while large safety margins are economically not viable. Conclusion. If some power units in the electric propulsion system (EPS) fail, extra costs would be spent on docking the vessel, dismounting of good equipment and hull structures to remove out-of-order equipment. Regulatory documenttation does not specify the scope of EPS components’ checkup after transportation or storage. Technical measures to ensure reliability of EPS elements include diagnostics of EPS elements prior to their installation on board the ship and during commissioning trials. Diagnostic tools of foreign make have more functional capabilities as compared to Russian instruments. Choice of specific devices and decisions to go for extra costs to further develop the Russian instruments should be based on feasibility studies. New regulations are required for testing rectifier transformers for electrodynamic withstand at short-circuit fault, as well as development and modernization of regional inter-industry shock test facilities.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43907263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Full-scale extrapolation method for propeller model test data","authors":"A. Yakovlev, T. Zin.","doi":"10.24937/2542-2324-2022-1-399-31-42","DOIUrl":"https://doi.org/10.24937/2542-2324-2022-1-399-31-42","url":null,"abstract":"in model and full-scale conditions. The purpose is to develop a similar methods for extrapolation of propeller model test data to the full-scale. Materials and methods. Propeller parameters are simulated as per the improved numerical method of E. Papmel. The flow around cylindrical section profiles of blades and hub is simulated as per the methods of boundary integral equations and integral calculation methods for the boundary layer with consideration of laminary-to-turbulent transition. Main results. Development of the method taking into account scale effect for propellers. The method has been applied to extrapolate model test data to the full scale. Conclusion. The method is of practical value for modern propeller design.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43286279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electric stealth of marine robotics against non-contact seabed mines","authors":"O. Malyshev, V. Éiduk, V. Khoroshev, A. Yakovlev","doi":"10.24937/2542-2324-2022-1-399-150-158","DOIUrl":"https://doi.org/10.24937/2542-2324-2022-1-399-150-158","url":null,"abstract":"Object and purpose of research. This paper investigates marine robots to estimate possible effect of environmental changes upon their stealth against local electrometric seabed threats, like non-contact mines. Materials and methods. This paper continues the series of studies analyzing stealth of marine objects as per system-approach methodology and theoretical principles of optimal signal identification against noisy background. Main results. The paper discusses possible ways for improving electric stealth of marine robotics and suggests a mathematical model for estimation of possible spectral parameters of near-seabed electric interference depending on the environment. The study yielded the estimates of possible electrometric detection for local seabed assets depending on electric dipole moment of the target, electric conductance of sea water and intensity of electric interference near the seabed. Conclusion. The results of these studies pave way to the development of electric stealth standards for marine robotics, as well as to the development of marine robotic technology control methods taking into account the necessity to ensure their stealth for non-contact seabed mines with electric fuses.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48614194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dissipative properties of three-layered composite structures. 2. Solution method","authors":"B. Yartsev, V. Ryabov, L. Parshina","doi":"10.24937/2542-2324-2022-1-399-55-64","DOIUrl":"https://doi.org/10.24937/2542-2324-2022-1-399-55-64","url":null,"abstract":"Object and purpose of research. This paper discusses a three-layered plate made up by two rigid anisotropic layers and soft isotropic medium layer of viscoelastic polymer. Each of the two rigid layers is an anisotropic structure formed by a finite number of arbitrarily oriented orthotropic viscoelastic composite layers. The purpose of this work is to develop a numerical solution method for decaying vibration equations of three-layered unsupported rectangular plates. Materials and methods. The system of algebraic equations is constructed as per Ritz method using Legendre polyno-mials as coordinate functions. The first step is to find real solutions. To find complex natural frequencies of the system, their initial values are taken as real natural frequencies thus found, with subsequent calculation of complex frequencies as per the method of third-order iterations. Main results. This paper discusses the results of convergence analysis for a numerical solution of differential motion equations with respect to an unsupported rectangular three-layered plate with transversally isotropic rigid layers. The material for these rigid lay-ers is uni-directional carbon-reinforced plastic (CRP) with elastic dissipation properties, within the investigated range of frequencies and temperatures, independent on its vibration frequency. For the soft isotropic medium layer of viscoelastic polymer, temperature-frequency curve governing the real part of complex elasticity modulus and mechanical loss coefficient is taken into account. Validation of the mathematical model and the numerical solution method, the comparison of calculated and experimental natural frequencies and mechanical loss coefficients for the two variants of three-layered unsupported plate has demonstrated their good correlation. Conclusion. This paper suggests and validates the numerical solution method for decaying vibration equations of three-layered unsupported rectangular plate made up by two rigid monoclinic layers and soft isotropic medium layer of viscoelastic polymer.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45578642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pneumatic-jet propulsor for Arctic lifeboat: efficiency justification","authors":"M. Sergeev, V. Tarovik, N. Valdman, A. Labuzov","doi":"10.24937/2542-2324-2022-1-399-197-210","DOIUrl":"https://doi.org/10.24937/2542-2324-2022-1-399-197-210","url":null,"abstract":"Object and purpose of research. This paper reviews the findings of efficiency justification study for pneumatic-jet propulsion of Arctic lifeboat. These results lead to the conclusion that this non-conventional type of propulsion could be a promising solution for fast escape beyond the hazard zone in case of emergency. Materials and methods. The results presented in this paper are based on well-studied and proven methods of solid mechanics, variable-mass mechanics and heat transfer. The relevance of the task of personnel evacuation from marine facilities in ice conditions is confirmed by the summary analysis of publications and patents about this topic, as well as by the experience of KSRC researchers. Main results. The study yielded the data on the lifeboat’s kinematics, as well as the curves of kimematic parameters for various types of the propellant. It also analysed the stability of pneumatic-jet propulsor operation in design conditions under effect of thermal and inertial disturbances. The results obtained for the closed lifeboat’s emergency escape from the hazard zone have shown that this type of lifeboat propulsion surely has practical potential. Conclusion. Pneumatic-jet propulsion might considerably increase the evacuation process efficiency in terms of the fast escape from the hazard zone. Simple design and operation principle reduce the time needed to prepare for the emergency escape. Also, this type of propulsion features robustness against long-term thermal disturbances with respect to its design condi-tions. Pre-defined safety radius may be ensured through variation of the propellant’s thermodynamic properties.","PeriodicalId":33210,"journal":{"name":"Trudy Krylovskogo gosudarstvennogo nauchnogo tsentra","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49028571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}