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C. Werner and R.S.R. Gorla

Abstract

The dynamic bone remodeling process is a computationally challenging research area that struggles to understand the actual mechanisms. It has been observed that a mechanical stimulus in the bone greatly affects the remodeling process. A 3D finite element model of a femur is created and a probabilistic analysis is performed on the model. The probabilistic analysis measures the sensitivities of various parameters related to the material properties, geometric properties, and the three load cases defined as Single Leg Stance, Abduction, and Adduction. The sensitivity of each parameter is based on the calculated maximum mechanical stimulus and analyzed at various values of probabilities ranging from 0.001 to 0.999. The analysis showed that the parameters associated with the Single Leg Stance load case had the highest sensitivity with a probability of 0.99 and the angle of the force applied to the joint of the proximal femur had the overall highest sensitivity

Open access

Iwona Adamiec-Wójcik, Andrzej Nowak and Stanisław Wojciech

Abstract

Dry electrostatic precipitators (ESPs) are widely used for purification of exhaust gases in industrial applications. Maintenance of their high efficiency depends primarily on periodical cleaning of the collecting electrodes (CEs). Dust removal (regeneration of CEs) is realized by inducing periodical vibrations of the electrodes. The paper presents results of vibration modelling of a system of CEs; the results were obtained by means of the finite element method, the hybrid finite element method, the finite strip method and a model formulated using Abaqus. Numerical results are compared with those obtained from experimental measurements. Conclusions concerning numerical effectiveness and exactness of the methods are formulated and reasons for differences are discussed.

Open access

Iwona Adamiec-Wójcik, Andrzej Nowak and Stanisław Wojciech

Abstract

The rigid finite element method (RFEM) has been used mainly for modelling systems with beam-like links. This paper deals with modelling of a single set of electrodes consisting of an upper beam with electrodes, which are shells with complicated shapes, and an anvil beam. Discretisation of the whole system, both the beams and the electrodes, is carried out by means of the rigid finite element method. The results of calculations concerned with free vibrations of the plates are compared with those obtained from a commercial package of the finite element method (FEM), while forced vibrations of the set of electrodes are compared with those obtained by means of the hybrid finite element method (HFEM) and experimental measurements obtained on a special test stand.

Open access

Maksym Grzywiński and Iwona Pokorska

Abstract

The paper deals with some aspects of structural sensitivity analysis in shell structures. The finite element method has been used for modeling of cylindrical structure. The direct differentiation method has been applied in solution of the problem considered. The examples of sensitivity have been presented concerning displacement sensitivity to variations of thickness in cylindrical shell structural element clamped at boundaries under uniformly distributed pressure. The algorithms presented have been prepared and programmed in the POLSAP code system [1].

Open access

Ryszard Sygulski, Michał Guminiak and Łukasz Polus

Abstract

The stability of the element of a steel welded girder subjected to bending and shear forces is considered. The considered element is a rectangular plate supported on boundary. The type of a plate boundary conditions depend on the types (thickness) of the stiffeners. Considered plate is loaded by in-plane forces causing bending and shear effects. The Finite Element Method was applied to carry out the analysis. Additionally the Boundary Element Method in terms of boundary-domain integral equation was applied to evaluate the critical shear loading.

Open access

M. Dhamodaran, S. Jegadeesan and R. Praveen Kumar

Abstract

This paper presents a fundamental and accurate approach to study numerical analysis of fluid flow and heat transfer inside a channel. In this study, the Finite Element Method is used to analyze the channel, which is divided into small subsections. The small subsections are discretized using higher number of domain elements and the corresponding number of nodes. MATLAB codes are developed to be used in the analysis. Simulation results showed that the analyses of fluid flow and temperature are influenced significantly by the changing entrance velocity. Also, there is an apparent effect on the temperature fields due to the presence of an energy source in the middle of the domain. In this paper, the characteristics of flow analysis and heat analysis in a channel have been investigated.

Open access

Krzysztof Kowalski, Lech Nowak, Łukasz Knypiński and Paweł Idziak

Abstract

The paper considers the influence of core saturation on the dynamics of magnetostrictive fast-acting actuator. The field-circuit mathematical model of the dynamic operation of the capacitor-actuator system is applied. Two kinds of magnetostrictive core nonlinearity are taken into account. It has been proved that the saturation of the B-H curve practically does not affect the current, and capacitor voltage waveforms, but significantly affects a core elongation waveform. The computed results are compared with experimental ones.

Open access

Balázs Móczár, Zsuzsanna Polgár and András Mahler

Abstract

Design and modelling of raft foundations and selecting the value of coefficient of vertical subgrade reaction are still actively discussed topics in geotechnical and structural engineering. In everyday practice, soil–structure interaction is mostly taken into account by using the theory of ‘beam on elastic foundation’, in which the soil is substituted by a certain set of coefficients of subgrade reaction. In this study, finite element analysis of a building was performed using a geotechnical software (Plaxis 3D), which is capable of modelling the subsoil as a continuum, and a structural software (Axis VM), which uses the concept of ‘beam on elastic foundation’. The evaluation of the results and recommendations for everyday engineering practice are introduced in this paper.

Open access

Juraj Hrabovský, Roman Gogola, Justín Murín and Tibor Sedlár

Abstract

In this contribution, the analysis of ice-shedding from Aluminium Conductor Steel Reinforced (ACSR) power lines is presented. The impact of the icing position on the overhead power lines, the resulting jump height, and impact on attachment tension points after ice-shedding is examined. In the numerical simulations the effective material properties of the ACSR conductor is calculated using the homogenisation method. Numerical analysis of one power line and double-bundle power lines with icing over the whole range or only on certain sections of single and double-bundle power lines are performed

Open access

Mario A. González-Montenegro, Roberto Jordan, Arcanjo Lenzi and Jorge P. Arenas

Abstract

A numerical method is developed for estimating the acoustic power of any baffled planar structure, which is vibrating with arbitrary surface velocity profile. It is well known that this parameter may be calculated with good accuracy using near field data, in terms of an impedance matrix, which is generated by the discretization of the vibrating surface into a number of elementary radiators. Thus, the sound pressure field on the structure surface can be determined by a combination of the matrix and the volume velocity vector. Then, the sound power can be estimated through integration of the acoustic intensity over a closed surface. On the other hand, few works exist in which the calculation is done in the far field from near field data by the use of radiation matrices, possibly because the numerical integration becomes complicated and expensive due to large variations of directivity of the source. In this work a different approach is used, based in the so-called Propagating Matrix, which is useful for calculating the sound pressure of an arbitrary number of points into free space, and it can be employed to estimate the sound power by integrating over a finite number of pressure points over a hemispherical surface surrounding the vibrating structure. Through numerical analysis, the advantages/disadvantages of the current method are investigated, when compared with numerical methods based on near field data. A flexible rectangular baffled panel is considered, where the normal velocity profile is previously calculated using a commercial finite element software. However, the method can easily be extended to any arbitrary shape. Good results are obtained in the low frequency range showing high computational performance of the method. Moreover, strategies are proposed to improve the performance of the method in terms of both computational cost and speed.