: Automatic position control of the solar cell (APCoSC) is a project of the system, whose task is to direct the surface of the photovoltaic cell perpendicular to the sunrays falling on it and to follow the sun. The main parts are the base and pole, on which the cell is mounted. The base consists of a fixed part that provides a stable mounting on the ground, and a rotating part with mounted motor, which can perform a full 360 * rotation. The mast ends with a handle which, can tilt the solar panel automatically up to 90 degrees vertically by using a motor. The sun position sensor is built of 4 ambient light photosensors (APDS) arranged in the shape of a plus, enclosed in a casing, to which the sun's rays fall through the round opening. The case can be attached directly to the solar cell, or a handle using an adapter, in such a way as to form a parallel plane with the cell. The STM32 microcontroller manages the system and engine operation. The sun position sensor can work at a temperature of -30 to 85 Celsius, which ensures its universal use in many places on the earth. The photovoltaic cell produces the most energy when the sun's rays fall perpendicular to its surface, which is why the automatic tilt adjustment is used. In large cities, APCoSC is used on flat roofs of houses, where there are many obstacles such as other buildings around. The system adapts itself to the position of the sun and selects the most favourable position of the solar panel in real time.
{"title":"AUTOMATIC POSITION CONTROL OF THE SOLAR CELL","authors":"Ł. Magnuszewski, K. Sapiołko, M. Rećko","doi":"10.21495/71-0-239","DOIUrl":"https://doi.org/10.21495/71-0-239","url":null,"abstract":": Automatic position control of the solar cell (APCoSC) is a project of the system, whose task is to direct the surface of the photovoltaic cell perpendicular to the sunrays falling on it and to follow the sun. The main parts are the base and pole, on which the cell is mounted. The base consists of a fixed part that provides a stable mounting on the ground, and a rotating part with mounted motor, which can perform a full 360 * rotation. The mast ends with a handle which, can tilt the solar panel automatically up to 90 degrees vertically by using a motor. The sun position sensor is built of 4 ambient light photosensors (APDS) arranged in the shape of a plus, enclosed in a casing, to which the sun's rays fall through the round opening. The case can be attached directly to the solar cell, or a handle using an adapter, in such a way as to form a parallel plane with the cell. The STM32 microcontroller manages the system and engine operation. The sun position sensor can work at a temperature of -30 to 85 Celsius, which ensures its universal use in many places on the earth. The photovoltaic cell produces the most energy when the sun's rays fall perpendicular to its surface, which is why the automatic tilt adjustment is used. In large cities, APCoSC is used on flat roofs of houses, where there are many obstacles such as other buildings around. The system adapts itself to the position of the sun and selects the most favourable position of the solar panel in real time.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133112568","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}
: Many engineering problems are extremely demanding to solve even on recent hardware. Numerical solutions of these problems on parallel computers can significantly reduce computational time by performing selected tasks concurrently. This paper deals with tuning up the parallel load balancing framework of the finite element software, which is based on domain decomposition paradigm for distributed memory model. The paper describes the technique to determine the actual weights comparing computational performance of individual processing units. These weights are fundamental inputs for mesh (re)partitioning that has to be performed at the beginning of the simulation and whenever the load imbalance is significant. The capabilities and performance of the proposed technique are evaluated on the benchmark problem and discussed. Abstract: Many engineering problems are extremely demanding to solve even on recent hardware. Numerical solutions of these problems on parallel computers can significantly reduce computational time by performing selected tasks concurrently. This paper deals with tuning up the parallel load balancing framework of the finite element software, which is based on domain decomposition paradigm for distributed memory model. The paper describes the technique to determine the actual weights comparing computational performance of individual processing units. These weights are fundamental inputs for mesh (re)partitioning that has to be performed at the beginning of the simulation and whenever the load imbalance is significant. The capabilities and performance of the proposed technique are evaluated on the benchmark problem and discussed.
{"title":"ON TUNING OF FINITE ELEMENT LOAD BALANCING FRAMEWORK","authors":"M. Bošanský, B. Patzák","doi":"10.21495/71-0-61","DOIUrl":"https://doi.org/10.21495/71-0-61","url":null,"abstract":": Many engineering problems are extremely demanding to solve even on recent hardware. Numerical solutions of these problems on parallel computers can significantly reduce computational time by performing selected tasks concurrently. This paper deals with tuning up the parallel load balancing framework of the finite element software, which is based on domain decomposition paradigm for distributed memory model. The paper describes the technique to determine the actual weights comparing computational performance of individual processing units. These weights are fundamental inputs for mesh (re)partitioning that has to be performed at the beginning of the simulation and whenever the load imbalance is significant. The capabilities and performance of the proposed technique are evaluated on the benchmark problem and discussed. Abstract: Many engineering problems are extremely demanding to solve even on recent hardware. Numerical solutions of these problems on parallel computers can significantly reduce computational time by performing selected tasks concurrently. This paper deals with tuning up the parallel load balancing framework of the finite element software, which is based on domain decomposition paradigm for distributed memory model. The paper describes the technique to determine the actual weights comparing computational performance of individual processing units. These weights are fundamental inputs for mesh (re)partitioning that has to be performed at the beginning of the simulation and whenever the load imbalance is significant. The capabilities and performance of the proposed technique are evaluated on the benchmark problem and discussed.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"92 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129325509","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}
: In this contribution, we focus on numerical simulation of discrete elastoplastic microstructures with periodic boundary conditions. The idea of nonuniform transformation field analysis, originally proposed by Michel and Suquet, is used for simplification of the given problem by reducing the number of internal variables represented by plastic strains. For that purpose, the plastic strains are approximated by linear combinations of selected plastic modes. Two approaches to the selection of plastic modes are proposed and compared using a simple two-dimensional example. Their accuracy is evaluated by comparing the results with the exact solution.
{"title":"NONUNIFORM TRANSFORMATION FIELD ANALYSIS APPLIED TO DISCRETE ELASTOPLASTIC MICROSTRUCTURE","authors":"K. Mikeš, M. Jirásek, J. Zeman","doi":"10.21495/71-0-251","DOIUrl":"https://doi.org/10.21495/71-0-251","url":null,"abstract":": In this contribution, we focus on numerical simulation of discrete elastoplastic microstructures with periodic boundary conditions. The idea of nonuniform transformation field analysis, originally proposed by Michel and Suquet, is used for simplification of the given problem by reducing the number of internal variables represented by plastic strains. For that purpose, the plastic strains are approximated by linear combinations of selected plastic modes. Two approaches to the selection of plastic modes are proposed and compared using a simple two-dimensional example. Their accuracy is evaluated by comparing the results with the exact solution.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131210447","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}
: Pressure loss analysis is carried out in the sub parts of the control valve. Attention is devoted to the pressure loss on protective strainer, to the pressure loss in valve chamber and in the diffuser. The influence of the flow vortex under the cone on the loss in the diffuser is analysed. The flow in the valve is considered for specific operational characteristics of the turbine.
{"title":"PRESSURE LOSS ANALYSIS IN THE STEAM TURBINE CONROL VALVE","authors":"L. Bednář, L. Tajč, M. Miczán, M. Hoznedl","doi":"10.21495/71-0-45","DOIUrl":"https://doi.org/10.21495/71-0-45","url":null,"abstract":": Pressure loss analysis is carried out in the sub parts of the control valve. Attention is devoted to the pressure loss on protective strainer, to the pressure loss in valve chamber and in the diffuser. The influence of the flow vortex under the cone on the loss in the diffuser is analysed. The flow in the valve is considered for specific operational characteristics of the turbine.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131792071","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}
: Steel production and processing are connected with high temperatures. Due to a reaction between hot surface of the steel and oxygen contained in surrounding atmosphere, oxides are formed on the surface of the steel. Created layer of oxides is called scales and has influence on cooling and quality of steel. Thickness and structure of scale layer are influenced by chemical composition of the steel, temperature and atmosphere during oxidation. Scale layer can be considerably porous which has a significant influence on thermal conductivity of this layer, because air pores have much lower thermal conductivity compared to scales. Steel samples were prepared and porosity of scale layer was studied. Further, the average thermal conductivity of porous scale layer was determined for different regimes of oxidation by FEM modelling. It was found that the average thermal conductivity of porous scale layer is influenced not only by porosity of scale layer, but also by distribution of air pores, which can has a significant effect.
{"title":"STUDY OF THERMAL CONDUCTIVITY OF THE POROUS OXIDE LAYER","authors":"O. Resl, M. Chabičovský, H. Votavová","doi":"10.21495/71-0-315","DOIUrl":"https://doi.org/10.21495/71-0-315","url":null,"abstract":": Steel production and processing are connected with high temperatures. Due to a reaction between hot surface of the steel and oxygen contained in surrounding atmosphere, oxides are formed on the surface of the steel. Created layer of oxides is called scales and has influence on cooling and quality of steel. Thickness and structure of scale layer are influenced by chemical composition of the steel, temperature and atmosphere during oxidation. Scale layer can be considerably porous which has a significant influence on thermal conductivity of this layer, because air pores have much lower thermal conductivity compared to scales. Steel samples were prepared and porosity of scale layer was studied. Further, the average thermal conductivity of porous scale layer was determined for different regimes of oxidation by FEM modelling. It was found that the average thermal conductivity of porous scale layer is influenced not only by porosity of scale layer, but also by distribution of air pores, which can has a significant effect.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123230561","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}
The basic parameters of a radio proximity sensor include its sensitivity to single (one-time) impacts with different values. Single impacts are both a desirable parameter used for example to trigger the power source during a projectile shot and very undesirable in sense of safety reason for instance in the case of a fall of a projectile with a sensor on a hard surface. The paper presents a description of the measurement stand and the method of its calibration necessary to correctly execute one-time impacts of specific values during research of radio proximity sensors used in artillery projectiles.
{"title":"STAND FOR TESTING SENSITIVITY IMPACT OF RADIO PROXIMITY SENSORS","authors":"S. Grzywiński, S. Żygadło","doi":"10.21495/71-0-133","DOIUrl":"https://doi.org/10.21495/71-0-133","url":null,"abstract":"The basic parameters of a radio proximity sensor include its sensitivity to single (one-time) impacts with different values. Single impacts are both a desirable parameter used for example to trigger the power source during a projectile shot and very undesirable in sense of safety reason for instance in the case of a fall of a projectile with a sensor on a hard surface. The paper presents a description of the measurement stand and the method of its calibration necessary to correctly execute one-time impacts of specific values during research of radio proximity sensors used in artillery projectiles.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114636781","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}
Mobile robot on-road navigation requires fusion of both global and local sensory information with an emphasis on the road detection processing. The paper deals with the road detection based on convolution neural networks (CNN) using commonly available tools such as TensorFlow and Keras. The road is defined by its linear boundaries. Network output is formed by the road definition together with classification parameters and serves as a local sensor in Kalman filter based localization. CNN based road detection is currently capable to successfully detect about 90% of images.
{"title":"UTILIZATION OF CONVOLUTION NEURAL NETWORK BASED ROAD DETECTION IN MOBILE ROBOT LOCALIZATION","authors":"J. Krejsa, S. Vechet","doi":"10.21495/71-0-203","DOIUrl":"https://doi.org/10.21495/71-0-203","url":null,"abstract":"Mobile robot on-road navigation requires fusion of both global and local sensory information with an emphasis on the road detection processing. The paper deals with the road detection based on convolution neural networks (CNN) using commonly available tools such as TensorFlow and Keras. The road is defined by its linear boundaries. Network output is formed by the road definition together with classification parameters and serves as a local sensor in Kalman filter based localization. CNN based road detection is currently capable to successfully detect about 90% of images.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124682946","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}
A. L. Popov, D. Chelyubeev, A. Levitin, V. M. Kozintsev, A. Chentsov
: The stress state estimates accounting for plasticity are obtained at residual stress evaluation performed by hole-drilling method and out-of-plane ESPI. The plasticity zone in the sample is present prior to the probe hole drilling. The sample is a steel composite disc, assembled by fitting rings on the plug. The initial stress distribution in the composite elastic-ideal plastic disk accounting for the formation of a plastic zone in the covering ring is obtained by the solution of Gadolin in elastoplastic formulation. A simple analytical algorithm to adjust the non-axisymmetric stresses in comparison with the calculation according to the elastic model is developed. The case of probe hole drilling in the area of plastic deformations is considered.
{"title":"DETERMINATION OF THE NON-AXISYMMETRIC STRESS STATE IN THE PLASTICITY ZONE BY THE HOLE-DRILLING METHOD WITH OUT-OF-PLANE ESPI","authors":"A. L. Popov, D. Chelyubeev, A. Levitin, V. M. Kozintsev, A. Chentsov","doi":"10.21495/71-0-295","DOIUrl":"https://doi.org/10.21495/71-0-295","url":null,"abstract":": The stress state estimates accounting for plasticity are obtained at residual stress evaluation performed by hole-drilling method and out-of-plane ESPI. The plasticity zone in the sample is present prior to the probe hole drilling. The sample is a steel composite disc, assembled by fitting rings on the plug. The initial stress distribution in the composite elastic-ideal plastic disk accounting for the formation of a plastic zone in the covering ring is obtained by the solution of Gadolin in elastoplastic formulation. A simple analytical algorithm to adjust the non-axisymmetric stresses in comparison with the calculation according to the elastic model is developed. The case of probe hole drilling in the area of plastic deformations is considered.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131944498","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}
: This contribution deals with the simple planar asymmetric pin-connected truss with 3 members. The ways and methods of derivations and solutions according to theories of first and second order and other possible linearizations are shown (i.e. internal forces, reactions, elongations, stresses). There are applied linear and nonlinear approaches and their simplifications via Taylor’s series. Finally, the errors of all approaches are evaluated and compared.
{"title":"COMPARATIVE STUDY OF SIMPLE TRUSS SOLVED ACCORDING TO THE THEORIES OF 1ST AND 2ND ORDER","authors":"K. Frydrýšek, M. Jahodová, Z. Morávková","doi":"10.21495/71-0-117","DOIUrl":"https://doi.org/10.21495/71-0-117","url":null,"abstract":": This contribution deals with the simple planar asymmetric pin-connected truss with 3 members. The ways and methods of derivations and solutions according to theories of first and second order and other possible linearizations are shown (i.e. internal forces, reactions, elongations, stresses). There are applied linear and nonlinear approaches and their simplifications via Taylor’s series. Finally, the errors of all approaches are evaluated and compared.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133334012","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}
: This paper presents the results of research on linear losses in a new ventilation system based on channels with a rounded rectangle cross-section. The friction coefficients of linear pressure losses referred to the unit of the straight length of the duct section 1 m l − as well as generalized dimensionless friction coefficient of linear pressure losses − are presented. The main achievement of the paper is the statement that the lambda coefficient can replace the coefficients l for all 79 examined duct cross-sections.
{"title":"LINEAR PRESSURE LOSSES COEFFICIENTS IN A NEW VENTILATION SYSTEM","authors":"K. Peszyński","doi":"10.21495/71-0-279","DOIUrl":"https://doi.org/10.21495/71-0-279","url":null,"abstract":": This paper presents the results of research on linear losses in a new ventilation system based on channels with a rounded rectangle cross-section. The friction coefficients of linear pressure losses referred to the unit of the straight length of the duct section 1 m l − as well as generalized dimensionless friction coefficient of linear pressure losses − are presented. The main achievement of the paper is the statement that the lambda coefficient can replace the coefficients l for all 79 examined duct cross-sections.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130793699","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}
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