Chosen Numerical Algorithms for Interval Finite Element Analysis

AbstractOur paper presents chosen computational algorithms for solution of finite element models with structural uncertainties. An application of the chosen approaches will be presented–the first one, a simple combination of only inf-values or only sup-values; the second one presents full combination of all inf-sup values; the third one uses the optimizing process as a tool for finding out an inf-sup solution and last one is the Monte Carlo method as a comparison tool

Modeling of multiaxial state of stress and determine the fatigue lifetime for aluminum alloy during cyclic loading under in-and-out of phase shift φ = 0° and φ = 90°

This article deals with determining of fatigue lifetime of structural materials during by multiaxial cyclic loading. Thetheoretical part deals with the fatigue and with the criterions for evaluation of multiaxial fatigue lifetime. The experimental part deals with modeling of combined bending - torsion loading and determining the number of cycles to fracture in region low-cycle and high-cycle fatigueand also during of loading with the sinusoidal wave form under in phase φ = 0° and out phase φ = 90°.This article deals with determining of fatigue lifetime of structural materials during by multiaxial cyclic loading. The theoretical part deals with the fatigue and with the criterions for evaluation of multiaxial fatigue lifetime. The experimental part deals with modeling of combined bending - torsion loading and determining the number of cycles to fracture in region low-cycle and high-cycle fatigue and also during of loading with the sinusoidal wave form under in phase φ = 0° and out phase φ = 90°

Numerical study of large scale truss construction with structural uncertainties

The paper deals with efficiency and usability problem for the chosen solution methods for mechanical systems with structural uncertainties. They are significantly influencing the analysis results and the analysis itself. An application of the chosen approaches will be presented – the first one, a simple combination of only inf-values or only sup-values; the second one presents full combination of all inf-sup values; the third one uses the optimizing process as a tool for finding out an inf-sup solution and last one is Monte Carlo method as a comparison tool.The paper deals with efficiency and usability problem for the chosen solution methods for mechanical systems with structural uncertainties. They are significantly influencing the analysis results and the analysis itself. An application of the chosen approaches will be presented – the first one, a simple combination of only inf-values or only sup-values; the second one presents full combination of all inf-sup values; the third one uses the optimizing process as a tool for finding out an inf-sup solution and last one is Monte Carlo method as a comparison tool

Optimization of the Induction Heating Process in Order to Achieve Uniform Surface Temperature

AbstractThe physics of the induction heating is based on coupling of the electromagnetism and heat transfer. The main heat source during induction heating is resistive heating caused by eddy currents in the heated specimen. The geometrical position of the inductors influences the final surface temperature distribution. There are many technological processes which require uniform surface temperature like process of induction hardening. The scope of the article is to show the numerical approach to optimize geometrical dimensions of the induction heating process in order to reach uniform surface temperature on heated specimen

The simulation and the experimental verification of the influence of the tig – welding of the aluminium alloy ALMGSI07 on changes of the mechanical properties in comparison with the basic material

The aim of this investigation is to evaluate the influence on fatigue behavior of the welded aluminum alloy AlMgSi07. For the experimental measurement of fatigue of these welds, it is needed to analyse all the changes, which will occur in the weld material in comparison with the basic material. The modern computer simulation and the experimental verification are strong tools for achievement of the required results, for instance a change of the structure, residual stress, a range of the heat affected zone, a deformation of the workpiece etcThe aim of this investigation is to evaluate the influence on fatigue behavior of the welded aluminum alloy AlMgSi07. For the experimental measurement of fatigue of these welds, it is needed to analyse all the changes, which will occur in the weld material in comparison with the basic material. The modern computer simulation and the experimental verification are strong tools for achievement of the required results, for instance a change of the structure, residual stress, a range of the heat affected zone, a deformation of the workpiece et

Methods of pre-identification of TITO systems

The content of this article is the presentation of methods used to identify systems before actual control, namely decentralized control of systems with Two Inputs, Two Outputs (TITO) and with two interactions. First, theoretical assumptions and reasons for using these methods are given. Subsequently, two methods for systems identification are described. At the end of this article, these specific methods are presented as the pre-identification of the chosen example. The Introduction part of the paper deals with the description of decentralized control, adaptive control, decentralized control in robotics and problem formulation (fixing the identification time at the existing decentralized self-tuning controller at the beginning of control and at the beginning of any set-point change) with the goal of a new method of identification. The Materials and methods section describes the used decentralized control method, recursive identification using approximation polynomials and least-squares with directional forgetting, recursive instrumental variable, self-tuning controller and suboptimal quadratic tracking controller, so all methods described in the section are those ones that already exist. Another section, named Assumptions, newly formulates the necessary background information, such as decentralized controllability and the system model, for the new identification method formulated in Pre-identification section. This section is followed by a section showing the results obtained by simulations and in real-time on a Coupled Drives model in the laboratory. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.European Regional Development Fund under the project CEBIA-Tech [CZ.1.05/2.1.00/03.0089]; Ministry of Education, Science, research and Sport of the Slovak Republic [1247/2018]Ministerstvo školstva, vedy, výskumu a športu Slovenskej republiky; European Regional Development Fund, ERDF: CZ.1.05/2.1.00/03.008

Numerical methods for analysis of mechanical systems with uncertain parameters

The paper presents new and improved numerical methods designed for analysis of mechanical systems with uncertain parameters. Uncertain parameters in mechanical systems are described by means of possibility theory. The main representatives of this theory are fuzzy and interval numbers. Algorithms using interval and fuzzy numbers are incorporated into the analysis. The possibilities and efficiency of suggested methods and algorithms are tested by programs created in the environment of the software package MATLAB

Modeling and Experimental Analysis of the Aluminium Alloy Fatigue Damage in the case of Bending – Torsion Loading

AbstractThe article deals with determining of fatigue lifetime of structural materials during by multiaxial cyclic loading. The theoretical part focuses on fatigue and criterions for evaluation of the multiaxial fatigue lifetime. The experimental part deals with modeling of combined bending -torsion loading and determining the number of cycles to fracture in region low-cycle fatigue and also during of the loading with the sinusoidal wave form under in phase φ = 0°. Based on the experimental results the fatigue design curves are compared to fatigue data from base metal and weldments

Comparison study of the computational methods for eigenvalues IFE analysis

The goal of the paper is to present a non-traditional computational tool for structural analysis with uncertainties in material, geometric and load parameters. Uncertainties are introduced as bounded possible values— intervals. The main objective has been to propose algorithms for interval modal and spectral computations on FEM models suggested by authors and their comparison with Monte Carlo

Numerical methods for analysis of mechanical systems with uncertain parameters

The paper presents new and improved numerical methods designed for analysis of mechanical systems with uncertain parameters. Uncertain parameters in mechanical systems are described by means of possibility theory. The main representatives of this theory are fuzzy and interval numbers. Algorithms using interval and fuzzy numbers are incorporated into the analysis. The possibilities and efficiency of suggested methods and algorithms are tested by programs created in the environment of the software package MATLAB