Orona Sa

Hernani, Spain
Hernani, Spain
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McCloskey A.,University of Mondragon | Arrasate X.,University of Mondragon | Hernandez X.,Orona Sa | Gomez I.,University of Mondragon | Almandoz G.,University of Mondragon
Mechanical Systems and Signal Processing | Year: 2018

Electrical motors are widely used and are often required to satisfy comfort specifications. Thus, vibration response estimations are necessary to reach optimum machine designs. This work presents an improved analytical model to calculate vibration response of an electrical machine. The stator and windings are modelled as a double circular cylindrical shell. As the stator is a laminated structure, orthotropic properties are applied to it. The values of those material properties are calculated according to the characteristics of the motor and the known material properties taken from previous works. Therefore, the model proposed takes into account the axial direction, so that length is considered, and also the contribution of windings, which differs from one machine to another. These aspects make the model valuable for a wide range of electrical motor types. In order to validate the analytical calculation, natural frequencies are calculated and compared to those obtained by Finite Element Method (FEM), giving relative errors below 10% for several circumferential and axial mode order combinations. It is also validated the analytical vibration calculation with acceleration measurements in a real machine. The comparison shows good agreement for the proposed model, being the most important frequency components in the same magnitude order. A simplified two dimensional model is also applied and the results obtained are not so satisfactory. © 2017 Elsevier Ltd

Argatov I.I.,University of Mondragon | Argatov I.I.,Research Institute of Mechanical Engineering Problems | Gomez X.,University of Mondragon | Tato W.,University of Mondragon | Urchegui M.A.,Orona Sa
Wear | Year: 2011

The Archard's wear law based mathematical model of fretting wear between wires is applied to elaboration of the experimental results of the previously reported study of the wear degradation in a stranded steel wire rope subjected to cyclic bending over a sheave. It is shown that the dependence of the coefficient of wear on the contact pressure should be taken into account to explain the observed increase of the wear severity with a reduction of the shave diameter. Accordingly, a mathematical model of fretting wear based on the Archard-Kragelsky wear law was developed, and an example of calibration of the wear law parameters was given. Some implications to fatigue life estimations for stranded wire ropes are discussed. © 2011 Elsevier B.V.

Arrasate X.,University of Mondragon | Kaczmarczyk S.,University of Northampton | Almandoz G.,University of Mondragon | Abete J.M.,University of Mondragon | Isasa I.,Orona Sa
Mechanical Systems and Signal Processing | Year: 2014

Vertical vibrations affect passenger comfort during an elevator travel. This work presents the results of a study of vertical vibrations caused by torque ripple generated at the elevator drive system. Tests are performed on a 1:1 roping configuration laboratory model; the acceleration response at the suspended masses and at the drive machine, the machine shaft velocity and the three phase current intensities supplied to the machine are measured during several travels. The machine torque is estimated from the current intensities. A non-stationary model of an elevator is then developed to simulate the acceleration response. The model accommodates the drive system dynamics. The machine parameters are computed by means of the Finite Element Method simulation software FLUX. FLUX computes the amplitudes of the torque ripple and the radial forces at the air-gap. As the torque ripple computed by FLUX is smaller than that torque estimated from the machine currents, the latter is added as a perturbation to the controller generated torque. With respect to the car-counterweight-sheave-ropes assembly a five degree-of-freedom lumped-parameter model (LPM) and a novel distributed-parameter one (DPM) are developed. The elevator dynamics represented by the DPM is described by a partial differential equation set that is discretised by expanding the vertical displacements in terms of the linear stationary mode shapes of a system composed of three masses constrained by the suspension rope. The models are implemented in the MATLAB/Simulink computational environment and the system response is determined through numerical simulation. It is shown that the LPM forms a good approximation of the DPM. The frequency content of the computed and measured accelerations demonstrates that the elevator car vibrates at frequencies generated at the machine, especially when they are close to the system natural frequencies. © 2013 Elsevier Ltd. All rights reserved.

Cruzado A.,University of Mondragon | Cruzado A.,IMDEA Madrid Institute for Advanced Studies | Urchegui M.A.,Orona Sa | Gomez X.,University of Mondragon
Wear | Year: 2014

This paper completes a series of two papers in which a FE based methodology for the prediction wear scars in thin steel wires under fretting wear conditions is developed. In the first paper 'Finite element modeling and experimental validation of fretting wear scars in thin steel wires' a FE fretting wear simulation model for a common 90° crossed cylinder tribological arrangements was developed and validated. The second paper deals with modeling accurately the elliptical wear scars presented in wire rope systems, in contrast with the simpler circular wear scars presented in the 90° crossed cylinder configuration. The main parameters involved in the wear simulation (mesh size, simulation wear increments per fretting cycle and cycle jump δN) are calibrated to obtain the minimum computational time. An exhaustive validation methodology for elliptical wear scars is presented. The proposed model presents very good correlation with respect to the experimental results, predicting wear scars with errors less than 15%. This FE model is presented as a helpful tool for the wire rope designers in the analysis of the severity of the wear scars under different operational and constructive parameters, so that, due to the complex construction of wire ropes, the wires contact between them with different crossing angles. © 2014 Elsevier B.V.

Bartolome L.,University of Mondragon | Aurrekoetxea J.,University of Mondragon | Urchegui M.A.,Orona Sa | Tato W.,University of Mondragon
Materials and Design | Year: 2013

Thermoplastic polyurethane elastomers under cyclic loading-unloading conditions exhibit inelastic effects, mainly stress softening, hysteresis loss and residual strain. In order to discuss the sensitivity of these effects to deformation state (uniaxial tension and pure shear) and to work conditions (maximum strain, strain-rate and stretching direction), this study is concerned with inelastic effects of an extruded thermoplastic polyurethane elastomer when is subjected to loading-unloading cycles. Based on the behaviour of inelastic effects under both tensile conditions, the present work shows that stress softening and residual strain are sensitive to deformation state only when the maximum strain reached causes permanent set. Furthermore, the hysteresis loss shows an independent behaviour depending on maximum strain. Finally, the behaviour of the hysteresis loss and the residual strain is isotropic for the extruded thermoplastic polyurethane elastomer. © 2013 Elsevier Ltd.

Cruzado A.,University of Mondragon | Leen S.B.,National University of Ireland | Urchegui M.A.,Orona Sa | Gomez X.,University of Mondragon
International Journal of Fatigue | Year: 2013

This paper studies the effect of fretting on fatigue life reduction of thin steel wires, using the frictionally-induced multiaxial contact stresses obtained from a finite element wear model, validated in previous work. The fatigue life prediction model uses a critical-plane SWT approach in a 3D crossed cylinder problem. A new damage accumulation methodology for the adaptive mesh simulation, based on the cyclic material removal, has been developed. Four methods (Manson's universal slope, Muralidharan modified universal slopes, medians and fatigue S-N curves) for estimation of the fatigue coefficients of the wire have been used. Manson's method and medians method give lives closer to those obtained from fretting wear tests in thin steel wires. The other methods are more conservative. The methodology predicts correctly the life reduction of this component due to the increase of normal load (contact pressure), while it is not clearly predicted that an increase of the stroke reduces the life of these components as shown in the experimental testing. Guidelines for developing a more robust methodology are proposed. © 2013 Elsevier B.V. All rights reserved.

Cruzado A.,University of Mondragon | Urchegui M.A.,Orona Sa | Gomez X.,University of Mondragon
Wear | Year: 2012

Fretting wear is one of the main degradation mechanism produced in steel wire ropes. The experimental characterization of this phenomenon is economically costly and too much time consuming. With the aim to reduce this disadvantage, an optimized methodology for wear scars simulation has been developed. This paper presents the two relevant aspects of this methodology, which consist of the reduction of computational time and the validation of the wear scar with respect to the experimental data. This methodology has been implemented via the commercial FE code ABAQUS in a 90° crossed-cylinders configuration. With respect to the reduction in computational time the effect of mesh size, simulation wear increments per fretting cycle and cycle jump technique are studied. An optimum mesh size for minimal computational time that should be in the range from 3% to 4% of the final longitudinal wear width is defined. On the other hand, an optimum value of 40 increments per fretting cycle and 100 fretting cycles with the corresponding cycle jump is enough to simulate the wear scar in any conditions with differences in dimensions less than 4%, in comparison with more refined simulations. The results of the optimized model are validated with respect to the experimental data obtained by the tests carried out in a small sliding amplitudes tribometer for the same crossed cylinder configuration. The validation consists of three steps: wear scar dimensions, wear scar depth and wear scar volume. This procedure demonstrates that within an error of 10% this optimized method predicts accurately the wear scars. © 2012 Elsevier B.V.

Cruzado A.,University of Mondragon | Hartelt M.,BAM Federal Institute of Materials Research and Testing | Wasche R.,BAM Federal Institute of Materials Research and Testing | Urchegui M.A.,Orona Sa | Gomez X.,University of Mondragon
Wear | Year: 2010

Different fretting tests of thin steel wires under different conditions (loads, strokes, number of cycles and mean pressures) were performed. The wires used had 0.45 mm in diameter and the material was a cold-drawn eutectoid carbon steel (0.8% C) with a tensile strength over 2800 MPa. The tests were carried out with 90° "crossed cylinders" configuration varying the stroke, normal load and testing time (number of cycles). Afterwards the volumetric wear was obtained using surface profilometry with diamond stylus. With a classical study of the coefficient of wear with respect to the sliding distance, the results show that the wear coefficient increases with normal load and stroke, consequently, for the same sliding distance, the wear produced was higher when the load and/or stroke is increased. In this work, the coefficient of wear is decreasing continuously as the test is running. In order to analyze better the wear behaviour, another method, in which the volumetric wear is compared with respect to the Archard's loading factor, is proposed. As result of this method, two distinctive behaviours were detected; one corresponds to the running-in period with a more aggressive wear behaviour and the second one to the stable steady state period. In all the tests the running-in period was similar with regard to the wear rates but in the stable period the wear rates were increasing with higher loads or strokes. © 2010 Elsevier B.V. All rights reserved.

Egea A.,University of Mondraon | Almandoz G.,University of Mondraon | Poza J.,University of Mondraon | Ugalde G.,University of Mondraon | Escalada A.J.,Orona Sa
IEEE Transactions on Industry Applications | Year: 2012

This paper deals with the development of analysis tools for axial-flux permanent-magnet machines. Normally, the study of this kind of machine involves three-dimensional (3-D) finite element method (FEM) (FEM-3-D) due to the 3-D nature of the magnetic problem. As it is widely known, the FEM-3-D software could take too much time, and both definition and solving processes of the problem may be very arduous. In this paper, a novel analysis procedure for axial-flux synchronous machines is proposed. This method consists in the combination of 2-D FEM simulations with analytical models based on the Fourier-series theory. The obtained results prove that the proposed method could be a very interesting option in terms of time and accuracy. © 1972-2012 IEEE.

Bilbao E.,Ecole Polytechnique Federale de Lausanne | Barrade P.,Ecole Polytechnique Federale de Lausanne | Etxeberria-Otadui I.,IKERLAN - IK4 | Rufer A.,Ecole Polytechnique Federale de Lausanne | And 2 more authors.
IEEE Transactions on Industry Applications | Year: 2014

Efficiency and energy consumption reduction are becoming a key issue in elevation applications. Energy Storage Systems (ESS) can play a significant role in this field, together with their associated Energy Management Strategy (EMS) to optimize the overall behavior of the elevator. This paper presents an EMS based on Dynamic Programming (DP) for a stochastic application where the cost function is based on the stock management theory. For that purpose, an implementation methodology for DP-based EMS is also proposed. That methodology has been applied on an elevator where the system modeling has been carried out. Due to the stochastic behavior of the application, a novel representation method is also presented (General Energy and Statistical Description). The EMS has been implemented and validated experimentally on a real elevator with energy storage capability reducing grid power peaks by 65% and braking resistor energy losses up to 84%. © 1972-2012 IEEE.

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