Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 14
items per page: 25 50 75
Sort by:

Abstract

This work is an analysis of construction and creation of a 3D model of a wind turbine blade in a CAD environment, using SOLIDWORKS on the basis of forces influencing the blade, which were determined using WIATRAK 1.1 software. The presented process is related to the issues of 3D modelling of a wind turbine blade and simulation of fabrication process in the CAM environment.
Go to article

Abstract

This work analyzes the process of construction and manufacturing of a blade used in a wind turbine. The calculation scheme is presented for forces generated on the blade of a wind turbine and parameters are determined of weather conditions in which the designed element would be working. Subsequently, for the chosen aerodynamic profile the characteristics are calculated of its aerodynamic coefficients, which enables the establishing of the angle of attack which impacts the yield of wind engines. The presented process is an introduction to 3D modelling of a wind turbine’s blade and simulation of its creation in a CAM environment.
Go to article

Abstract

The paper reports on investigation and development of a flywheel device intended for an energy storage prototype. The goal was to design and experimentally verify the concept of self-integrated flywheel with smart control of energy flow and accumulation. The Flywheel Energy Storage System (FESS) must has high energy efficiency and structural robustness. Investigation on structural dynamics of the composite flywheel connected with outer type rotor was carried out using Finite Element Method. The FESS is designed to run in vacuum and is supported on low-energy, controlled, active magnetic bearings (AMBs). The flywheel device of 10 MJ energy density and a weight of 150 kg with two integrated rotors/generators of 50 kW power density each is intended to operate up to 40 000 rpm.
Go to article

Abstract

The effects of filling the core box cavity and sand compaction in processes of core production by blowing methods (blowing, shooting) depend on several main factors. The most important are: geometrical parameters of cavity and complexity of its shape, number, distribution and shape of blowing holes feeding sands as well as the venting of a technological cavity. Values of individual parameters are selected according to various criteria, but mostly they should be adjusted to properties of the applied core sand. Various methods developed by several researchers, including the authors own attempts, allow to assess core sands properties on the basis of special technological tests projecting the process into a laboratory scale. The developed criteria defining a degree or a filling ability factor provide a better possibility of assessing the core sand behavior during flowing and core box filling, which indicate the value and structure of the obtained compacting decisive – after hardening – for strength and permeability. The mentioned above aspects are analyzed – on the basis of authors’ own examinations - in the hereby paper.
Go to article

Abstract

A proper management of sand grains of moulding sands requires knowing basic properties of the spent matrix after casting knocking out. This information is essential from the point of view of the proper performing the matrix recycling process and preparing moulding sands with reclaimed materials. The most important parameter informing on the matrix quality – in case of moulding sands with organic binders after casting knocking out – is their ignition loss. The methodology of estimating ignition loss of spent moulding sands with organic binder– after casting knocking out - developed in AGH, is presented in the paper. This method applies the simulation MAGMA software, allowing to determine this moulding sand parameter already at the stage of the production preparation.
Go to article

Abstract

Theoretical problems concerning the determination of work parameters of the two-phase sand-air stream in the cores making process by blowing methods as well as experimental methods of determination of the main and auxiliary parameters of this process decisive on the cores quality assessed by the value and distribution of their apparent density are presented in the paper. In addition the results of visualisations of the core-box filling with the sand-air stream, from the blowing chamber, obtained by the process filming by means of the quick-action camera are presented in the paper and compared with the results of simulation calculations with the application of the ProCast software.
Go to article

Abstract

A navigation complex of an unmanned flight vehicle of small class is considered. Increasing the accuracy of navigation definitions is done with the help of a nonlinear Kalman filter in the implementation of the algorithm on board an aircraft in the face of severe limitations on the performance of the special calculator. The accuracy of the assessment depends on the available reliable information on the model of the process under study, which has a high degree of uncertainty. To carry out high-precision correction of the navigation complex, an adaptive non-linear Kalman filter with parametric identification was developed. The model of errors of the inertial navigation system is considered in the navigation complex, which is used in the algorithmic support. The procedure for identifying the parameters of a non-linear model represented by the SDC method in a scalar form is used. The developed adaptive non-linear Kalman filter is compact and easy to implement on board an aircraft.
Go to article

Abstract

The single-phase voltage loss is a common fault. Once the voltage-loss failure occurs, the amount of electrical energy will not be measured, but it is to be calculated so as to protect the interest of the power supplier. Two automatic calculation methods, the power substitution and the voltage substitution, are introduced in this paper. Considering the lack of quantitative analysis of the calculation error of the voltage substitution method, the grid traversal method and MATLAB tool are applied to solve the problem. The theoretical analysis indicates that the calculation error is closely related to the voltage unbalance factor and the power factor, and the maximum calculation error is about 6% when the power system operates normally. To verify the theoretical analysis, two three-phase electrical energy metering devices have been developed, and verification tests have been carried out in both the lab and field conditions. The lab testing results are consistent with the theoretical ones, and the field testing results show that the calculation errors are generally below 0.2%, that is correct in most cases.
Go to article

Abstract

In this paper a scaling approach for the solution of 2D FE models of electric machines is proposed. This allows a geometrical and stator and rotor resistance scaling as well as a rewinding of a squirrel cage induction machine enabling an efficient numerical optimization. The 2D FEM solutions of a reference machine are calculated by a model based hybrid numeric induction machine simulation approach. In contrast to already known scaling procedures for synchronous machines the FEM solutions of the induction machine are scaled in the stator-current-rotor-frequency-plane and then transformed to the torque- speed-map. This gives the possibility to use a new time scaling factor that is necessary to keep a constant field distribution. The scaling procedure is validated by the finite element method and used in a numerical optimization process for the sizing of an electric vehicle traction drive considering the gear ratio. The results show that the scaling procedure is very accurate, computational very efficient and suitable for the use in machine design optimization.
Go to article

Abstract

The site preference of some transition metals during B2-type ordering has been investigated in the ternary Cu0.5(Zn1–xMx)0.5 alloys with M = Ti, V, Ag, Au, Cr, Mn, Fe, Co, Ni, Nb, Mo, Hf, Ta, W, Re or Pt (x ≤ 0.01). The statistic-o-thermodynamical theory combined with the electronic theory of alloys has been used to calculate the partial ordering energies, partial short range order parameters and the order-disorder transformation temperatures. The values of partial short range order parameters have been used to determine the site preference of the metal M. The analysis shows that the metals M can be divided into two groups with regard to lattice site occupancy. One group comprising of Cr, Mn, Fe, Co, Ni, Nb, Mo, Hf, Ta, W, Re or Pt was found to prefer Zn sublattice sites, while the second group of Ti, V, Ag or Au atoms prefer Cu sublattice sites. It is found that order-disorder transformation temperature and the site preference of metal M both depend strongly on the partial ordering energies and ternary alloying addition of metal M.
Go to article

Abstract

Fatigue investigations of two 4XXX0-series aluminum alloys (acc. PN-EN 1706) within a range of fewer than 104 cycles at a coefficient of cycle asymmetry of R = –1 were performed in the current paper. The so-called modified low-cycle test, which provided additional information concerning the fatigue life and strength of the tested alloys, was also performed. The obtained results were presented in the form of diagrams: stress amplitude σa – number of cycles before damage N. On the basis of the microscopic images of sample fractures, the influence of the observed casting defects on the decrease of cycle numbers at a given level of stress amplitude were analyzed. Based on the images and dimensions of the observed defects, stress intensity factor KI was analytically determined for each. Their numerical models were also made, and stress intensity factor KI was calculated by the finite element method (FEM).
Go to article

Abstract

This paper presents a general overview of 2D mathematical models for both the inorganic and the organic contaminants moving in an aquifer, taking into consideration the most important processes that occur in the ground. These processes affect, to a different extent, the concentration reduction values for the contaminants moving in a groundwater. In this analysis, the following processes have been taken into consideration: reversible physical non-linear adsorption, chemical and biological reactions (as biodegradation/biological denitrification) and radioactive decay (for moving radionuclides). Based on these 2D contaminant transport models it has been possible to calculate numerically the dimensionless concentration values with and without all the chosen processes in relation to both the chosen natural site (piezometers) and the chosen contaminants.In this paper, it has also been possible to compare all the numerically calculated concentration values to the measured concentration ones (in the chosen earlier piezometers) in relation to both the new unpublished measurement series of May 1982 and the new set of parameters used in these 2D contaminant transport models (as practical verification of these models).
Go to article

Abstract

The effect of the initial porosity on the material response under multi-axial stress state for S235JR steel using the Gurson-Tvergaard-Needleman (GTN) material model was examined. Three levels of initial porosity, defined by the void volume fraction f₀, were considered: zero porosity for fully dense material without pores, average and maximum porosity according to the metallurgical requirements for S235JR steel. The effect of the initial porosity on the material response was noticed for tensile elements under multi-axial stress state defined by high stress triaxiality σₘ/σe = 1.345. This effect was especially noticeable at the range of the material failure. In terms of the load-bearing capacity of the elements, the conservative results were obtained when maximum value of f₀ = 0.0024 was used for S235JR steel under multi-axial stress state, and this value is recommended to use in the calculations in order to preserve the highest safety level of the structure. In usual engineering calculations, the average porosity defined by f₀ = 0.001 may be applied for S235JR.
Go to article

This page uses 'cookies'. Learn more