Abstract: Presentation of the numerical model describing a design and functionality of the prototype of surface condition detector is the paper subject. The detector, by monitoring the frictional coupling between so-called “tracking wheel” of the dedicated measuring transducer and a rail can analyse the condition of rail surface (presence of any factor that can deteriorate friction coefficient) . Signal generated at the detector outlet, carrying information about local condition of rail surface, can be used to adjust braking torque of vehicles or machines moving on a track. Authors expect that implementation of the method will eliminated dangerous elongation of braking distance of rail vehicles in the result of loss of adhesion. Structure of detector of rail surface condition is described and its principle of operation is presented in a form of numerical model. Results of numerical simulations are given and they are compared with the measurements taken on the testing facility in real conditions.
Abstract: The Earth’s gravity field tends to change due to various reasons. These are diverse processes occurring inside the Earth or changes initiated by human activity. The increasing accuracy of measurements has enabled to take into consideration fluctuations in the gravity field. The article presents research study on the effect of gravity potential describing variations in the gravity field affecting gravity field elements related to the performed measurements. Due to the effect of the disturbing potential, a change in gravity and the deviation of vertical and equipotential surface deformation have been determined. The paper has analyzed the disturbing effect of the material point or homogeneous sphere and has specified the possibilities of assessing the disturbing effect of any form of the homogeneous body. Based on the tidal potential induced by the celestial body, the disturbing effect of the Moon and Sun onto the Earth’s gravity field has been assessed. The carried out research indicates that the range of deformation changes in the equipotential surface of the Earth’s gravity field induced by the effect of the Moon is equal to 0.4824 m, whereas that of the Sun makes 0.1861 m. The conducted studies prove that, due to the effect of the Moon, the direction of the vertical, in terms of the Earth’s surface, tends to change up to 0.0541", and as a result of the Sun’s effect it could reach 0.0204". Having assessed the Lunisolar effect in the first order vertical network measurements in Lithuania, in a polygon with the perimeter of 451 km, it has been determined that the closing error of normal height difference has decreased by the factor of 1.3.
Abstract: The paper describes on-going research effort at detecting and localizing damage in plate-like structures using mode shape curvature based damage detection algorithm. The proposed damage index uses data on exclusively mode shape curvature from the damaged structure. This method was originally developed for beam-like structures. The article generalizes the method of plate-like structures characterized by two-dimensional mode shape curvature. To examine limitations of the method, several sets of simulated data are applied and the obtained results of the numerical detection of damage are validated by comparing them with the findings of the case of the experimental test. The simulated test cases include the damage of various levels of severity. In order to ascertain the sensitivity of the proposed method for noisy experimental data, numerical mode shapes are corrupted with different levels of random noise. Modal frequencies and corresponding mode shapes of an aluminium plate containing mill-cut damage are obtained via finite element models for numerical simulations and by using a scanning laser vibrometer (SLV) for the experimental study.
Abstract: The aim of this study is to develop a mathematical model of the lubricating oil viscosity changes during the exploitation time of the engine.The aim was achieved by measurements of dynamic viscosity of engine oil used in a passenger car Volkswagen Touran equipped with a turbocharged diesel engine with a capacity of 2.0 liters. The recommended interval for oil change in this engine model is 30000 km. Oil used in this study was Shell Helix AV-L (viscosity grade SAE 5W30, designation VW: 50700).Viscosity tests were made on a Haake MARS III using two measuring systems. The first consisted of a plate-cone system with Peltier element for temperature stabilization. The second one is the high shear rate chamber with temperature control thermostat co-operating with ultra-A40 AC200 which can operate at temperatures ranging from-40 °C to +200 °C. The high shear rate chamber, consisting of a measuring cylinder and the rotor, the shear rate can achieve up to 200000 s–1.Dynamic viscosity measurements were performed at temperatures ranging from 20 °C to 90 °C.The results of the research are shown in the graphs and in tabular form. Obtained graphs made it possible to determine characteristics of the oil ageing for each mileages, temperatures and shear rates.
Abstract: The paper deals with the kinematics problem of a four-degree-of-freedom manipulator and derives equations for forward and inverse kinematics. A simulation model has been created applying SolidWorks program. On the basis of modelling, a real object used for experimental research has been built. Numerical, analytical and experimental results have been compared.
Abstract: The article presents some aspects of several years of work on the use of the vibroacoustic method (Non-Destructive Testing) for assessing a turboprop engine from a trainer aircraft. The functioning engine does not have an operating system for measuring vibration, and therefore the current levels of vibrations and its changes in trends are not known. In order to extend its service life, performing a number of works was required. On the basis of assessing the current state of the engine, opportunities for further exploitation were identified thus developing methodology for evaluating technical condition regarding the whole population. The paper shortly describes the object and equivalent tests on the engine. The article focuses on the methods prepared for extending life between overhauls required for turboprop engines and discusses the results received during their implementation.
Abstract: Drawpieces made of advanced high-strength steel (AHSS) usable for production of self-supporting car bodies are characterized by the presence of the springback phenomenon caused by the stress relaxation of the elastic part which is the result of stamping. Its compensation requires proper verification of die tools. The presented paper describes a methodology using CAE for die design. The methodology solves an optimization problem determining the verified shape of die tools upon taking into account the consistence of the drawpiece shape with the shape postulated in the project. The real drawpiece was used to judge the usefulness of the methodology in die design.
Abstract: The numerous machine exploitation problems in the field of the experimental and numerical wear slide bearing determination problems demand to know information referring the features of the sequence of the existing wear process during the operation time. The above-mentioned information includes the velocity of the wear values increases during the particular time units of the operation and convergence and divergence properties of the wear value increases are very important. If we have two wear value increase processes, then very important is information which process is divergent more slowly. On the other hand, in comparison between two convergent processes, we must decide which process is convergent more quickly.
Abstract: Numerous problems of numerical calculations occurring in power-train tribology and transport concerning the process of determining the problems of worn out bearings demand more and more information referring to the anticipation of the wear of slide bearings in the succeeding years of machine operations. Therefore, the paper presents the methods for working towards solutions to some specific classes of second and higher order non-homogeneous recurrence equations with variable coefficients occurring in the hydrodynamic theory of the problems dealing with bearing wear. Contrary to linear recurrence equations with constant coefficients, linear recurrence equations with variable coefficients rarely have analytical solutions. Numerical answers to such equations are always practicable. With reference to a large number of analytical methods for solutions to linear recurrence equations with variable coefficients, three research directions are usually followed.The first one depends upon the successive determination of particular linear independent solutions to the considered recurrence equation. The second direction can be characterized by a reduction in the order of the recurrence equation for obtaining the first order always solved recurrence equation. The third direction of solutions to recurrence equations with variable coefficients contains the methods for analytical solutions by means of a summation factor.The majority of the general methods of analytical solutions to linear recurrence equations with variable coefficients constitute the adaptation of the methods applied in solutions to suitable differential equations. As regards the final conclusions, the application of the theory presented in this paper contains numerical solutions referring to the wear values of the slide journal-bearing system in the indicated period of operating time.
Abstract: The article presents the operation and structure of a dispersion adhesive applicator dedicated for printing industry. Contrary to the currently used solutions in which the length of the glue layer is defined by the geometry of the glue roller, the original device enables free formation of the relation between the bonding area and adhesive-free areas. Based on the analysis of geometrical and time dependencies characterising the designed device, a mechatronic control system was developed to enable repeated glue application synchronised with the markers commonly used in printing industry and applied onto the paper. Constructed based on a programmable PLC controller, the system has control over all crucial technological parameters of the process (temperature, glue amount, beginning and end of the bonding area). The user-device communication is interactive, and therefore an additional user panel (touch-screen) is employed. The developed solution was used for applying dispersion adhesives in a technological line for producing multilayer ID cards with RFID labels.