Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines最新文献

{"title":"Analysis of the strength of the fastening elements of a mechanical pedal with a cable drive","authors":"K. Holenko, O. Dykha, O. Rudyk","doi":"10.20998/2078-9130.2022.1.265433","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.265433","url":null,"abstract":"Strength indicators determination of mechanical pedals structural components of vehicles, in particular the elements of their fastening to the corresponding locations cable drive, is relevant due to the need to comply with the requirements for maximum efforts in accordance with UNECE Regulations No. 13 and No. 35 on the one hand and ensure a sufficient margin of safety according to the technical operating conditions cable drives - on another hand. The topic considered in article acquires additional practical benefit from the point of view of assessing the margin of mechanical pedal components safety under critical operating conditions, which are the basis of boundary conditions in the formation of the task - strength analysis of certain parts by the finite element method in ANSYS environment. \u0000It should be understood that the above analysis is only one of mandatory stages of pedal simulation tests, because, being a relatively simple unit, a mechanical pedal really must be designed in such a way that critical loads should destroy the least critical replaceable elements of the assembly, but not the drives and their corresponding aggregates activated via remote control cable.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125069500","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":"On the modeling of boundary conditions for determining the critical speeds of rotation of rotors","authors":"O. Trubayev, A. Larin","doi":"10.20998/2078-9130.2022.2.270867","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.2.270867","url":null,"abstract":"The article is devoted to the definition of boundary conditions that allow achieving adequate results when calculating the critical speeds of rotation of rotors based on finite element models. Experimental determination of the frequencies of free vibrations of a laboratory rotor on ball bearings was carried out using a vibration measuring complex developed by the authors. Numerical studies of the free vibrations of a laboratory rotor and a cylindrical pipe with a wall thickness to length ratio of 1/10 were performed on the basis of a three-dimensional finite element model under various boundary conditions. Movable and fixed cylindrical hinges corresponding to floating bearings are used as supports in the calculation scheme of the laboratory rotor. Due to the fact that the dimensions of the bearings along the length of the shaft are small compared to the total length, it is assumed in the calculation model that the shaft is hinged along the edges at separate points of one circle on each bearing. Shaft mounting options at two, four and eight points are considered. The options for fastening a cylindrical pipe in the extreme sections at two points, a quarter of a circle and a full circle are considered. Comparison of experimental and numerical results, solutions obtained analytically and on the basis of the finite element method is carried out. An analysis of the modes of natural vibrations showed that with various options for fixing a cylindrical pipe, vibration modes arise associated with the deformation of the pipe as a shell. For example, when fixing a pipe along a quarter of a circle, among the forms №1-№10, only the second corresponds to the deformation of the pipe as a beam. The results of the study of free vibrations of a laboratory rotor show that the best option for boundary conditions, which makes it possible to approach the results of the experiment, is fastening on each bearing at two points located on the neutral line of the cross section when the rotor is bent. Numerical studies of the eigen frequencies of a cylindrical pipe show that it is with this type of boundary conditions that one can obtain results that are closest to the analytical solution.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116368092","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":"Research into the loading of a removable module for transportation of long freight in a combined train by the train ferry","authors":"G. Vatulia, A. Lovska, S. Myamlin, M. Pavliuchenkov","doi":"10.20998/2078-9130.2022.1.264322","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.264322","url":null,"abstract":"The article presents the results of determination of the loading of a removable module for transportation of long freight in a combined train by the train ferry. The article describes the results of the mathematical modelling of the dynamic loading on a removable module placed on the flat car during rolling motion of the train ferry. It suggested that the flat car was rigidly fastened and displaced together with the deck. The displacements of the removable module relative to the flat car frame and the freight relative to the removable module were neglected. The mathematical model was solved with the method of variation of constants and confirmed by means of calculation in Mathcad. It was found that the maximum value of acceleration to the flat car with the removable module was about 2.35 m/s2 (0.24g). The value of acceleration obtained was included in the strength calculation for the removable module. The calculation was based on the finite element method and realized in SolidWorks Simulation with the Mises criterion. The finite element model was formed with spatial isoparametric tetrahedrons. The results of the calculation demonstrated that the maximum equivalent stresses were in the contact area between the vertical posts and the fittings; they amounted to 284.7 MPa. The stresses obtained were lower than the allowable values by 17.5%. The yield strength of the structural material was taken as the allowable stress. The equilibrium stability factor for the removable module was also determined. The strength of the removable module on the flat car without proper displacements and with the long freight inside was provided at the roll angles of the train ferry up to 25°. The results of the research will be of value for those who are dealing with development of transport facilities with better operational efficiency for combined transportation.Key words: removable module, dynamic loading, strength, equilibrium stability, train ferry transportation.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114497448","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":"Коливання балок при розтязі в умовах повзучостіTIONS","authors":"O. Tatarinova, Oleg Morackovsky, D. Breslavsky","doi":"10.20998/2078-9130.2022.2.268919","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.2.268919","url":null,"abstract":"Статтю присвячено підходу та аналітичним методам прогнозування змінювання власних коливань балок в умовах дії сил поздовжнього розтягу при повзучості. На базі класичного рівняння коливань балок при розтязі отримано метод оцінювання власних частот, які можуть змінюватись при повзучості. Отримано вирази для поздовжньої сили, що залежить від фізико-механічних параметрів матеріалу. Знайдено співвідношення для визначення часу істотного впливу повзучості на власні частоти. За допомогою отриманого виразу для значення часу до руйнування балки з використанням параметру суцільності Качанова запропоновано підхід до визначення впливу на частоти процесу накопичення прихованих пошкоджень. Випадок великих прогинів балки розглянуто у геометрично нелінійній постановці з використанням методу багатьох масштабів з розвиненням розв’язку за малим параметром. Розглянуто процеси динамічної повзучості, в якій прискорення швидкості деформацій повзучості в матеріалі забезпечується внеском амплітудних напружень. Розв’язок отриманого рівняння виконується методом зважених відхилів у формі Гальоркіна. Отримано залежності для визначення швидкості релаксації напружень у балці при повзучості. Оцінено граничні значення сили стискання з точки зору втрати стійкості стрижня в заданих умовах повзучості та можливості виникнення коливань. Виконано розрахункове моделювання та отримано результати, що дозволяють визначити чутливість частот власних коливань балок, виготовлених з різних конструктивних матеріалів, до розтягу при повзучості. Розглянуто жароміцні сплави, леговані сталі, титановий, алюмінієвий сплави та олов’яно-свинцевий припій при температурах, які притаманні типовим експлуатаційним умовам конструктивних елементів, що з них виготовляються. Показано, що найменший вплив повзучості на власні частоти виявлено для легких сплавів. За допомогою отриманих співвідношень проаналізовано частоти нелінійних коливань, що можуть відбуватись у балках, та побудовано скелетну криву.\u0000Ключові слова: Коливання, власні частоти, повзучість, балка, розтяг, згин.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124232381","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":"Elastic properties and strength criterion of reinforced composite","authors":"Mykhailo Bohatyr, G. Lvov","doi":"10.20998/2078-9130.2022.1.265161","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.265161","url":null,"abstract":"Woven composite materials are increasingly being used in various fields of modern technology. Unlike composites reinforced with straight fibers, they have a higher shear stress loading strength and improved impact strength characteristics. Woven composites have good technological properties. Blanks with carbon or glass fabrics are well laid out on tooling in the manufacture of thin-walled structural elements of complex shapes. The technological advantages of woven composite materials have determined the economic feasibility of their widespread use in the aviation industry and the automotive industry. The paper presents a numerical method for identifying the elastic and strength characteristics of woven carbon fiber based on the results of a micromechanical analysis of a representative volume based on the known properties of the matrix and fibers. Numerical experiments on uniaxial tension in the x, y, and z axes directions have been carried out. Modeled shift in three coordinate planes. The strength characteristics of the representative volume of the composite under conditions of tension and compression in three directions, shifts in three planes, and three biaxial tensions are determined.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131961801","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":"Mathematical modeling of the vertical load of a hopper-type container placed on a long-base structure of a platform car","authors":"G. Vatulia, A. Lovska, Yevhen Krasnokutskyi","doi":"10.20998/2078-9130.2022.1.264323","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.264323","url":null,"abstract":"Higher operational efficiency of container transportation can be achieved by putting into operation hopper containers. The special feature of a container is its inclined end and sidewalls, which makes it possible to self-discharge bulk freight through the discharging hatches forming the floor. The vertical loading of a hopper container placed on the long-base flat car was determined with the mathematical modelling. The mathematical model described the translational movement of a flat car in the vertical plane, i.e. bouncing oscillations. The flat car for the calculation consisted of three bodies: bearing structure loaded with four containers and two 18-100 bogies. The containers were considered as attached masses that completely repeated the movement pattern of the bearing structure of the flat car in the vertical plane. The mathematical model also included the elastic characteristics of the track. The calculation was made for the containers placed on a long-base 13-7024 flat car. The mathematical model was solved with the Runge-Kutta method in MathCad. The initial conditions were equal to zero. It was found that the maximum acceleration in the mass center of the bearing structure of a flat car loaded with hopper containers was 1.28 m/s2, which did not exceed the allowable values. The vertical dynamic coefficient was 0.13. The motion of the flat car was estimated as excellent.The results of the research will be of value for those who are dealing with development of advanced container structures with better operational efficiency for container transportation.Key words: transport mechanics, hopper container, dynamic loading, dynamic characteristics, container transportation.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115933895","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":"Numerical modeling of the processes of irreversible deformation of rings under explosive loading","authors":"O. Tatarinova, D. Breslavsky","doi":"10.20998/2078-9130.2022.1.262153","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.262153","url":null,"abstract":"the quasi-static problem is discussed. The equations of the incremental theory of plasticity are used to describe fast deformation. The numerical simulation method is implemented based on the use of the Arbitrary Lagrange-Euler (ALE) approach, in which the sequence of boundary value problems in the current configuration of the solid is solved using the Finite Element Method. An axisymmetric finite element of a triangular cross-section was used for modeling. The main system of equations is presented, which, when using the Finite Element Method, describes the deformation of axisymmetric bodies in the current configuration. At each stage of the calculation in the current configuration, the initial problem is solved numerically using the finite difference method. When the limiting value of the strain tensor components is reached, according to the ALE algorithm, the finite element model is rebuilt with the implementation of new boundary conditions. To build a computational model, the RD program was used, in which a two-dimensional model of a section of an axisymmetric body is surrounded by a mesh of special elements. A presented approach for the implementation of the specified boundary conditions of an axisymmetric body in finite element modeling is discussed. Calculations of irreversible deformation were carried out in a program developed on the basis of using the FEM Creep software package in the case of finite strains. Comparison of the numerical simulation data with the experimental results of other authors, obtained in the investigations of the explosive loading of aluminum rings set on a sphere, is presented. The experimental data are processed and the constants included in the constitutive equation, using the hardening law, are determined. Satisfactory agreement between the calculated and experimentally obtained values of the radial strain of the rings at different times is shown. \u0000Key words: numerical simulation, axisymmetric problem, finite strains, FEM, program, explosive loading, aluminum alloy.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"155 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123392956","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":"Dependence of static strength of large crystals of synthetic diamond type ib of octaedric habitus, after chemical-thermal time and time","authors":"M. Tsysar, Anatolii Zakora, A. Babak, Sergii Ivakhnenko, O. Zanevskii, Halina Ilnitska, I. Zakora","doi":"10.20998/2078-9130.2022.1.253664","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.1.253664","url":null,"abstract":"Increasing demands on the quality of drilling tools are forcing us to revise the traditional methods of their production and develop new alternative technologies. Some issues related to the possibility of increasing the efficiency of a drilling tool using diamond single crystals are considered. It has been suggested that a further reserve for improving the quality of drill bits lies in the use of large, high-strength, non-magnetic diamonds. Scientific research in this area has shown that the efficiency of the drilling process largely depends on the mechanical properties of single crystals, such as tensile strength and hardness. The grains operate under a load close to critical, which can lead to the complete destruction of single crystals instead of gradual chipping with the formation of new cutting edges. The results of an experimental study of the influence of individual stages of the drilling tool manufacturing process, namely, chemical-thermal treatment and annealing at 1150°C, on the static strength of large type Ib synthetic diamond crystals with an octahedral habit are presented. The dependence of this quantity on the geometric dimensions of single crystals was obtained for the first time. The achieved maximum value of static strength was 8750 N. It was experimentally confirmed that with an increase in the breaking load, the size of the fragments decreases. In order to ensure sufficient strength of the cutting part of the drilling tool, it is advisable to limit the size of single crystals to 1000–1200 µm, since the critical load values ​​for them are higher than for crystals whose size is 1300 µm or more, which, according to the theory, is associated with an increase in the number of defects and inclusions in proportion to size. The performed analysis made it possible to make adjustments to aspects of the manifestation of the scale effect when testing the strength properties of diamond single crystals.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121537376","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":"Computer simulation of the deformed state and strength of the frame structure of a heavy uav","authors":"D. Breslavsky, V. N. Konkin, O. Marusenko, V. Kortunov","doi":"10.20998/2078-9130.2022.2.270148","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.2.270148","url":null,"abstract":"COMPUTER SIMULATION OF THE DEFORMED STATE AND STRENGTH OF THE FRAME STRUCTURE OF A HEAVY UAV \u0000The paper is devoted to the presentation of the computer simulation results of the stress-strain state and evaluation of the low-cycle strength of the frame structure of a heavy unmanned aerial vehicle (UAV) of the quadcopter type, the prototype of which was developed at NTU \"KhPI\". The quadcopter is built on the basis of the use of four internal combustion engines (ICE), which provide lifting power. The cycle of calculations of the stress-strain state of the frame structure, carried out to select the option required from the point of view of ensuring the required stiffness and strength, was performed using the Finite Element Method (FEM). A macro has been developed for use in the engineering software, which allows you to select the best parameters from the point of view of the required stiffness and strength of the frame. The results of calculations of the variant implemented in the design of the created UAV prototype are presented. According to the results of the analysis of the stress-strain state, it is shown that the structural parameters chosen for the steel frame of the prototype fully satisfy the conditions of minimal deformation and short-term strength. The constants included in the evolution equation for the damage parameter describing low-cycle loading, which occurs during UAV abnormal landings, have been determined. An elastic-plastic analysis of the frame structure deformation for the conditions of dangerous landing of the quadcopter was performed. Calculations of hidden damage accumulation processes in the most heavily loaded frame beams have been carried out. For the steel frame implemented in the created prototype, the possibility of satisfactory resistance to low-cycle deformation under abnormal landing conditions is demonstrated. It is shown that due to the insufficient low-cycle strength of the aluminum alloy structure, it is necessary to make structural changes in the new version of the UAV frame that is being designed. \u0000Key words: computer simulation, quadcopter, macro, beam structure, stress-strain state, FEM, low-cycle strength, damage.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124506765","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":"Algorithm, implementation, data preparation, calculation of statics and dynamics of beam lattice structures in SSKA KIDYM","authors":"Yu. Andrieiev, Oleksiі Marusenko","doi":"10.20998/2078-9130.2022.2.270159","DOIUrl":"https://doi.org/10.20998/2078-9130.2022.2.270159","url":null,"abstract":"The problem of developing a universal analytical description and an algorithm for automatic computer calculations of dynamics, statics and kinetostatics of mechanical models of structures, which include beam lattices, is considered. These can be calculations of transient processes, steady-state free and forced vibrations, determination of equilibrium positions and stress-strain state under static and dynamic loads, etc. The structure itself can be flat or spatial, fixed or movable on a plane or in space. Various equipment can be attached to it. It is shown how it is possible to analytically describe a part of the structure, which is a beam lattice, in a language for preparing computer data of a special computer algebra system KiDyM (SCAS KiDyM). Based on the theory of elasticity of Bernoulli-Euler beams, 2 forms of the canonical representation of the potential energy of an elastic beam are obtained. This allows us to introduce a new element into the accepted language for describing mechanical models - a “Beam”, for which the positions of coordinate systems associated with its extreme sections, its geometric and physical parameters are indicated. The position of these sections is determined by the lattice nodes, as by solid bodies. Thus, the generalized coordinates of the mechanical model are determined. An algorithm for the formation of elements of mechanical models of SCAS KiDyM has been developed. This gives the elastic structure of the mechanical model. The tools available in this program automatically build the equations of dynamics and statics, i.e. form a mathematical model, according to which dynamic and static calculations are carried out. The article demonstrates the proposed method in detail on the example of calculating the deformation of a window frame. A comparison of the results with calculations based on an independent program was made. \u0000Key words: lattice beam structures, Bernoulli-Euler beams, a special system of computer algebra, calculations of the dynamics of spatial mechanical models.","PeriodicalId":186064,"journal":{"name":"Bulletin of the National Technical University «KhPI» Series: Dynamics and Strength of Machines","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124087747","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}