The vibration characteristics of stiffened plates with cutouts subjected to in-plane partial edge loadings at one end at the plate boundaries are studied using the finite element method. Buckling loads and vibration frequencies are determined for different cutout ratios and extent of partial edge loading at one end. In the structural modelling, the plate and the stiffeners are treated as separate elements where the compatibility between these two types of elements is maintained. The main elegance of the formulation lies in the treatment of the stiffeners. The stiffeners can be placed anywhere within the plate element, and need not be placed on the nodal lines. The vibration characteristics are discussed and the results are compared with those available in the literature. Numerical results are presented for a range of cutout to plate size from 0 to 0.8.
A.K.L. Srivastava, S.R. Pandey and A. Kumar
P. Szota, D. Strycharska, S. Mróz and A. Stefanik
An analysis of the roll wear in the multi-strand rolling of reinforced concrete ribbed bars has been made in the study. In the technology under consideration, the longitudinal partition of the band takes place in special slitting passes, while the separation of individual strands – in idle separating rollers. During rolling, the slitting passes undergo fast wear compared to the remaining passes of the rolling line. The paper reports the results of theoretical and experimental examinations, on the basis of which the wear of the slitting passes in the 16 mm-diameter ribbed bar three-strand rolling process has been determined. The theoretical examination was done using the Forge2011® software program, while experimental tests were carried out in a D350 medium-size continuous rolling mill. Based on the analysis of the investigation results, the wear coefficient was established for the slitting passes, which allowed the determination of their quantitative wear.
J. Piekło and M. Maj
The article presents the concept of division of a carbon block into single cathode sections to reduce stresses that occur during thermal shock accompanying the operation of pouring cast iron into a shaped groove in which the current-carrying steel pin is mounted. The temperature field and the state of stress were determined by FEM. Experimental measurements were used to determine the core displacement during pouring operation. The calculations were verified by thermovision and photoelastic method. Based on the temperature field and stress field analysis, a method for the block division into sections has been proposed, resulting in a significant reduction of the stress level.
Qinfen Lu, Yunyue Ye and Jianxin Shen
The car access time is a key parameter, especially in a huge stereo-garage, where this one should be decreased as much as possible. This paper proposes a novel stereo-garage. Adopting the linear induction motors (LIMs), the system has a simple structure and rapid response capability. In the stereo-garage, several LIMs are installed below the crossbeam on a lifting platform, and several LIMs are fixed on the top of a moving frame. During the operation of LIMs, the moving frame moves forward and backward to reach the required parking place, whereas the crossbeam moves horizontally in order to take or store the vehicle rapidly. All these LIMs are the same and should be designed at a low frequency. The influences of key structure parameters and dynamic performances are investigated, based on FEM. The predicted results are validated by a prototype. Finally, the designed LIMs are successfully applied in two 8-layer stereo-garages.
A. Świątoniowski, D. Woźniak and J. Szostak
The essential aspect of the MEFASS rolling process is introducing the cyclic axial counter movement of the rolls transverse to the direction of rolling in the course of a band pass through a rolling gap. The effect of a change in the way of deformation obtained in this manner makes it possible to set in one roll pass a deformation several times larger than it is possible in a conventional process. In this paper, upon the basis of the computer model of the MES process, supported by experimental research, the analysis of the influence exerted by the shape of the surface of roll barrels upon the distribution of the intensity of stresses σi and deformations εi in the section of the band being rolled, and also upon the kinematic and force parameters of the process.
Christoph Schmuelling, Christian Kreischer and Marek Gołebiowski
Commonly, the Park model is used to calculate transients or steady-state operations of synchronous machines. The expanded Park theory derives the Park equations from the phase-domain model of the synchronous machine by the use of transformations. Thereby, several hypothesis are made, which are under investigation in this article in respect to the main inductances of two different types of synchronous machines. It is shown, that the derivation of the Park equations from the phase-domain model does not lead to constant inductances, as it is usually assumed for these equations. Nevertheless the Park model is the most common analytic model of synchronous machines. Therefore, in the second part of this article a method using the evolution strategy is shown to obtain the parameters of the Park model.
Ivan Balázs and Jindřich Melcher
The paper deals with geometrically nonlinear analysis of steel beams of monosymmetric thinwalled cross-sections loaded perpendicularly to the plane of symmetry eccentrically to the crosssection shear centre. Numerical analysis of selected transversely loaded beams is performed using Dlubal RFEM code based on finite element method. Accuracy of interaction formula for bending with lateral torsional buckling and torsion is studied.
Bogdan Szybinski and Andrzej Trojnacki
The paper deals with experimental investigations of a set of metal wave-ring gaskets of different thickness and different assembly interference. The gaskets were examined under assembly conditions, i.e. pressed in their seats with no operating pressure applied. The electric resistance wire strain gauges were used to measure the circumferential and axial strains at the inner surface of the gaskets. The traces of contact at the working surface of the gaskets were measured after disassembly the gaskets from their seats. The material tests were carried out to determine the real mechanical properties of materials applied for the gaskets and the seats. The results of experiment were verified by FEM calculations and compared with the analytical approach based on the simplified shell model proposed for the gasket.
Przemysław Stasiuk, Aleksander Karolczuk and Wiesław Kuczko
Welded joints are areas of increased stresses in construction. The reason for this phenomenon is associated with the nonhomo-geneous mechanical, structural and geometrical properties of the weld seams. Generally, in the majority of the calculation it is assumed that the shape of the weld is uniform over the entire length and it is not deviating from the theoretical one. This article shows the distribution of stress in the butt-weld made of S355J2+N steel specimens. The shape of a joint was transferred to the finite element analysis by application of 3D scanning. Selected multiaxial fatigue criteria and probability mass function were used for a description of the results. Theoretical model prepared for comparison to the scanned joints was consistent with recommendations of International Institute of Welding for the effective notch method.
In order to obtain reliable results of computations in civil engineering, the numerical procedures that are used at the stage of design should be calibrated by comparison of the theoretical results with an observed behavior of previously modeled and then executed structures. The hybrid Finite Element code with an Artificial Neural Network inserted as a representation of a constitutive law, offers a possibility to adjust not only parameters of the constitutive relationships but also its qualitative form. Because of this, the representation of constitutive law by the ANN is presented in this paper. The constitutive data should be calibrated to fit well the observable values, measured in experiments. If the constitutive law is expressed by ANN, the inverse problem can be reduce to a training of the ANN inserted into the Finite Element code. An example of a solution of the inverse problem in calibration of constitutive law is presented. An identification of parameters of flow of pollutant in soils is described as another example of application of ANN in engineering