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Vibrations in Physical Systems最新文献

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Analysis of the Relationship between Selected Stability Assessment Indicators on The Example of Leaning out the Human Body from the Upright Position 以人体直立倾出为例分析稳定性评价指标间的关系
Vibrations in Physical Systems Pub Date : 2020-01-01 DOI: 10.21008/J.0860-6897.2020.2.19
Agata Matuszewska, J. Buśkiewicz
{"title":"Analysis of the Relationship between Selected Stability Assessment Indicators on The Example of Leaning out the Human Body from the Upright Position","authors":"Agata Matuszewska, J. Buśkiewicz","doi":"10.21008/J.0860-6897.2020.2.19","DOIUrl":"https://doi.org/10.21008/J.0860-6897.2020.2.19","url":null,"abstract":"The objective of this paper is to study the margin of stability when trying to lean out the body forward and backward. The centre of mass of the body, the velocity of the centre of mass and extrapolated centre of mass were calculated for four participants. The analyzed movement was recorded by using BTS Motion Capture system. Recordings, in which participants were unable to return to the upright position, were also observed. In these cases, it was verified the usefulness of extrapolated centre of mass for predicting the foot support area that enables maintaining the body balance. The relationship between the applied stability indicators and anthropometric parameters was determined. The preliminary results obtained confirm the validity of the use of selected parameters in tests and in assessment of the stability of the human body, and indicate the directions of further tests for a larger group of participants and other movement activities.","PeriodicalId":38508,"journal":{"name":"Vibrations in Physical Systems","volume":"31 1","pages":"2020219-1-2020219-8"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68248420","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}
引用次数: 0
Numerical simulations of the flows past rotating geometries 流动经过旋转几何形状的数值模拟
Vibrations in Physical Systems Pub Date : 2020-01-01 DOI: 10.21008/J.0860-6897.2020.3.18
J. Simon, W. Stankiewicz
{"title":"Numerical simulations of the flows past rotating geometries","authors":"J. Simon, W. Stankiewicz","doi":"10.21008/J.0860-6897.2020.3.18","DOIUrl":"https://doi.org/10.21008/J.0860-6897.2020.3.18","url":null,"abstract":"In the present paper the numerical approach for the modeling of the flow past rotating geometries is presented. Practical methods for two cases are described: the one where whole domain is moving with uniform angular velocity, where the rotation might be included in the governing equations only (in the terms related to Coriolis and centrifugal forces), and the one where part of the domain is rotating, whereas another one is stationary. The second case is illustrated by examples describing the steady and transient flow around a rotating propeller and by a centrifugal pump. Simulations are performed using OpenFOAM CFD solver, with the models covering flow rotation: MRF (multiple reference frame) and AMI (arbitrary mesh interface).","PeriodicalId":38508,"journal":{"name":"Vibrations in Physical Systems","volume":"31 1","pages":"2020318-1-2020318-8"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68248763","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}
引用次数: 0
Stiffness and Damping Coefficients of 8-lobe Journal Bearings 8叶滑动轴承的刚度和阻尼系数
Vibrations in Physical Systems Pub Date : 2020-01-01 DOI: 10.21008/J.0860-6897.2020.3.21
S. Strzelecki
{"title":"Stiffness and Damping Coefficients of 8-lobe Journal Bearings","authors":"S. Strzelecki","doi":"10.21008/J.0860-6897.2020.3.21","DOIUrl":"https://doi.org/10.21008/J.0860-6897.2020.3.21","url":null,"abstract":"High-speed rotating machinery, such as steam turbines, turbo-compressors, pumps, turbo pumps, accelerating gearboxes contain multilobe journal bearings. The bearings with 8 lobes are applied in bearing system of grinding spindle. The reasons for the application of such bearings are not too high temperatures of bearing operation and specific static and dynamic characteristics. Stiffness and damping coefficients of 8-lobe journal bearings with cylindrical and multilobe profile of lobes were calculated by means of perturbation method. Different values of bearing length to diameter ratio, relative clearance and lobe relative clearance were assumed. Reynolds', energy and viscosity equations were solved by means of iterative procedure. Adiabatic oil film, laminar flow in the bearing gap and aligned orientation of journal in the bearing were considered.","PeriodicalId":38508,"journal":{"name":"Vibrations in Physical Systems","volume":"31 1","pages":"2020321-1-2020321-8"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68249280","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}
引用次数: 0
Determination of the Sound Power Level of Modular Machines with Cyclic Operation Mode – Case Study 循环工作模式下组合机器声功率级的测定-案例研究
Vibrations in Physical Systems Pub Date : 2020-01-01 DOI: 10.21008/J.0860-6897.2020.1.01
B. Jakubek, R. Barczewski
{"title":"Determination of the Sound Power Level of Modular Machines with Cyclic Operation Mode – Case Study","authors":"B. Jakubek, R. Barczewski","doi":"10.21008/J.0860-6897.2020.1.01","DOIUrl":"https://doi.org/10.21008/J.0860-6897.2020.1.01","url":null,"abstract":"The sound power level as a parameter characterizing a sound source, as opposed to the sound pressure level, should theoretically not depend on the place of measurement and distance from the source. Therefore, it is often used as a basis for comparing machines and equipment in terms of noise emissions. Manufacturers usually specify this parameter in the technical documentation or on the equipment. The sound power level is also a necessary parameter for modelling the natural and working environment in terms of acoustics. The standards for methods of determining the sound power level define three classes of accuracy depending on the method and environment of measurement. The paper outlines the problems associated with determining the sound power level of non-standard machines in situ. The case study concerns a machine, a modular SRP (shelf ready packaging) production system that can be part of an extensive production line. Specific for this type of machine is the coexistence of many local sources generating sound of different nature, cyclic mode of operation and the possibility to set different capacity.","PeriodicalId":38508,"journal":{"name":"Vibrations in Physical Systems","volume":"31 1","pages":"2020101-1-2020101-12"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68247582","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}
引用次数: 0
Free Vibrations of Iso- and Orthotropic Plates Considering Plate Variable Thickness and Interaction with Water 考虑板厚变及与水相互作用的等各向异性和正交各向异性板的自由振动
Vibrations in Physical Systems Pub Date : 2020-01-01 DOI: 10.21008/J.0860-6897.2020.2.16
A. Lenartowicz, M. Guminiak
{"title":"Free Vibrations of Iso- and Orthotropic Plates Considering Plate Variable Thickness and Interaction with Water","authors":"A. Lenartowicz, M. Guminiak","doi":"10.21008/J.0860-6897.2020.2.16","DOIUrl":"https://doi.org/10.21008/J.0860-6897.2020.2.16","url":null,"abstract":"The natural vibrations of thin (Kirchhoff-Love) plates with constant and variable thickness are considered in the paper. Isotropic and orthotropic rectangular plates with different boundary conditions are analysed. The Finite Element Method and the Finite Difference Method are used to describe structural deformation. The elements of stiffness matrix are derived numerically using author’s approaches of localization of integration points. The plate inertia forces are expressed by diagonal, lumped mass matrix or consistent mass matrix. The presence of the external medium, which can be a fluid, is described by the fluid velocity potential of double layer and the fundamental solution of Laplace equation which leads to the fully-populated mass matrix. The influence of external additional liquid mass on natural frequencies of plate is analysed, too.","PeriodicalId":38508,"journal":{"name":"Vibrations in Physical Systems","volume":"31 1","pages":"2020216-1-2020216-8"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68248379","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}
引用次数: 2
Dynamic Characteristics of the Structure with Viscoelastic Dampers Combined with Inerters and Subjected to Temperature Changes 温度变化下粘弹性阻尼器与惯性器组合结构的动力特性
Vibrations in Physical Systems Pub Date : 2020-01-01 DOI: 10.21008/J.0860-6897.2020.2.22
Z. Pawlak, R. Lewandowski
{"title":"Dynamic Characteristics of the Structure with Viscoelastic Dampers Combined with Inerters and Subjected to Temperature Changes","authors":"Z. Pawlak, R. Lewandowski","doi":"10.21008/J.0860-6897.2020.2.22","DOIUrl":"https://doi.org/10.21008/J.0860-6897.2020.2.22","url":null,"abstract":"The purpose of the work is dynamic analysis of passive dampers used in structural systems to reduce excessive vibrations caused by wind or earthquakes. Special systems are considered that contain inerter, i.e. device using rotational inertia, in combination with a viscoelastic damper. The so-called fractional models of viscoelastic dampers describe their dynamic behavior in a wide frequency range using a small number of model parameters. To describe material behavior over a wider frequency range, the time-temperature superposition principle is used. The shifting factor is calculated from the well-known William-Landel-Ferry formula. This allows for determination of damper parameters at any temperature based on the parameters obtained at the reference temperature. Laplace transformation of the derived equations of motion leads to the non-linear eigenproblem, which could be solved using the continuation method. The influence of temperature on the dynamic characteristics of the system is examined.","PeriodicalId":38508,"journal":{"name":"Vibrations in Physical Systems","volume":"31 1","pages":"2020222-1-2020222-10"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68248479","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}
引用次数: 0
Vibroacoustic Condition Monitoring of the Complex Rotation System Based on Multilevel Signal Processing 基于多电平信号处理的复杂旋转系统振动声状态监测
Vibrations in Physical Systems Pub Date : 2020-01-01 DOI: 10.21008/J.0860-6897.2020.2.24
O. Pazdrii, N. Bouraou
{"title":"Vibroacoustic Condition Monitoring of the Complex Rotation System Based on Multilevel Signal Processing","authors":"O. Pazdrii, N. Bouraou","doi":"10.21008/J.0860-6897.2020.2.24","DOIUrl":"https://doi.org/10.21008/J.0860-6897.2020.2.24","url":null,"abstract":"This work is devoted to further research and improvement of the vibroacoustic condition monitoring of complex rotation system during operation. The low-frequency vibration and acoustic noise in the range 0-10 kHz is used as diagnostic information. We propose to use Bispectrum (BS) Analysis at the first level of signal processing, and Fractal Analysis of BS contour images at the second level of signal processing for the diagnosis of small imbalance of rotation system. The experimental studies of forced vibrations of the physical model (PM) of the rotation system are carried out under steady-state and non-steady-state rotation excitations. The results of the BS Analysis of vibroacoustical signals, which are emitted by a rotating PM during different excitation modes, are processed in order to determine fractal box-counting dimension (Minkowski dimension). The research shows that a small imbalance can be efficiently detected by the proposed multilevel signal processing in all modes of PM operation.","PeriodicalId":38508,"journal":{"name":"Vibrations in Physical Systems","volume":"31 1","pages":"2020224-1-2020224-6"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68248507","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}
引用次数: 0
Numerical Analysis of the Lower Limb Prosthesis Subjected to Various Load Conditions 不同载荷条件下下肢假体的数值分析
Vibrations in Physical Systems Pub Date : 2020-01-01 DOI: 10.21008/J.0860-6897.2020.3.09
M. Kowalczyk, H. Jopek
{"title":"Numerical Analysis of the Lower Limb Prosthesis Subjected to Various Load Conditions","authors":"M. Kowalczyk, H. Jopek","doi":"10.21008/J.0860-6897.2020.3.09","DOIUrl":"https://doi.org/10.21008/J.0860-6897.2020.3.09","url":null,"abstract":"","PeriodicalId":38508,"journal":{"name":"Vibrations in Physical Systems","volume":"31 1","pages":"2020309-1-2020309-11"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68248596","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}
引用次数: 2
Modeling of Sound Power Transmission within Duct Systems 管道系统内声功率传输的建模
Vibrations in Physical Systems Pub Date : 2020-01-01 DOI: 10.21008/J.0860-6897.2020.3.20
T. Stręk
{"title":"Modeling of Sound Power Transmission within Duct Systems","authors":"T. Stręk","doi":"10.21008/J.0860-6897.2020.3.20","DOIUrl":"https://doi.org/10.21008/J.0860-6897.2020.3.20","url":null,"abstract":"External boundaries of acoustic devices can channel sound propagation, and in some cases can create buildup or attenuation of acoustic energy within a confined space. In this paper, it is proposed an efficient practical numerical method (based on FEM) of calculation of attenuation of sound power transmission through ducts. The method shows its viability by presenting the reasonably consistent anticipation of the experimental result. One can observe the mechanical behaviour of the duct’s medium for lower frequencies (high transmission loss) and wave behaviour for higher frequencies (small or zero attenuation). The authors proved that mechanical vibrations of medium reduce the possibility of acoustic energy transmission in duct systems. The radiation impedance for the duct is calculated as well.","PeriodicalId":38508,"journal":{"name":"Vibrations in Physical Systems","volume":"31 1","pages":"2020320-1-2020320-6"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68249698","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}
引用次数: 0
Inertial Position Determination Under Vibration 振动下的惯性位置测定
Vibrations in Physical Systems Pub Date : 2020-01-01 DOI: 10.21008/J.0860-6897.2020.2.01
V. Avrutov, S. Lakoza, L. Ryzhkov, O. Sapegin
{"title":"Inertial Position Determination Under Vibration","authors":"V. Avrutov, S. Lakoza, L. Ryzhkov, O. Sapegin","doi":"10.21008/J.0860-6897.2020.2.01","DOIUrl":"https://doi.org/10.21008/J.0860-6897.2020.2.01","url":null,"abstract":"The main purpose of navigation systems is a position determination different moving objects. For standard inertial navigation systems algorithm, the initial position data are required. Normally these data may be determined by astronomical techniques or satellite and radio navigation systems. However, astronomical techniques depend on climate conditions and satellite and radio systems can be disturbed by electromagnetic countermeasures. It is proposed to use an Inertial Measurement Unit (IMU) and a navigation computer for autonomous determination of an initial position. IMU should be composed of three accelerometers, three gyroscopes and a signal processing circuit. The method proposed the latitude determination uses projections of the Earth’s rate measured by orthogonal IMU gyroscopes and projections of the gravity acceleration measured by orthogonal IMU accelerometers. Experimental tests of the IMU with a ring laser gyros triad and precision pendulum accelerometers confirmed the efficiency of the method on a fixed base. The behavior of the latitude determination under vibration is researched. The latitude determination under vibration was considered analytically by Power Spectral Density theory. It was estimated a variance of the latitude under the broad-band vibration. The method operability under harmonic and random vibration of the base at the real time is considered.","PeriodicalId":38508,"journal":{"name":"Vibrations in Physical Systems","volume":"31 1","pages":"2020201-1-2020201-10"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68247411","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}
引用次数: 1
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