Wyniki wyszukiwania - BazTech

1

Organization of reverse engineering using modern calculation methods in the process of reproducing a gears

Pacana Andrzej, Pacana Jacek, Straka Martin, Woźny Artur

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2023

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z. 170

371--382

EN

Purpose: The main purpose of this article is to present modern possibilities for the reproduction of a machine element. If there are no replacements for the damaged part, and there is no technical documentation, then the only options is to use reverse engineering (RE) methods to reproduce it. Design/methodology/approach: On the example of a damaged gear, the process of measuring the wheel and manufacturing a physical model using 3D printing. An additional step has been added to the classic reverse engineering process to modify the model to improve its strength. Findings: Strength analysis was carried out in the Abaqus program using the finite element method (FEM). Based on the results obtained, it was proposed to change the tooth profile of the gear, which will improve its durability. Research limitations/implications: An extension of the proposed scheme may be a modification of the production process in order to implement the reverse engineering method to the serial production of machine elements. Practical implications: The use of a modified reverse engineering (RE) process will not only allow the components to be reproduced but will also allow extended uptime of the components, and this will reduce production costs. Originality/value: The proposed new reverse engineering process can be successfully used to reconstruct machine components with even very complex shapes. The digital model obtained as a result of scanning has been used to improve the geometry of the toothed rim, but it can be successfully used for other analyses, research, or calculations.

2

Free vibration analysis of imperfect functionally graded sandwich plates: analytical and experimental investigation

Njim E.K., Bakhy S.H., Al-Waily M.

Archives of Materials Science and Engineering

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2021

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Vol. 111, nr 2

49--65

EN

Purpose: This paper develops a new analytical solution to conduct the free vibration analysis of porous functionally graded (FG) sandwich plates based on classical plate theory (CPT). The sandwich plate made of the FGM core consists of one porous metal that had not previously been taken into account in vibration analysis and two homogenous skins. Design/methodology/approach: The analytical formulations were generated based on the classical plate theory (CPT). According to the power law, the material properties of FG plates are expected to vary along the thickness direction of the constituents. Findings: The results show that the porosity parameter and the power gradient parameter significantly influence vibration characteristics. It is found that there is an acceptable error between the analytical and numerical solutions with a maximum discrepancy of 0.576 % at a slenderness ratio (a/h =100), while the maximum error percentage between the analytical and experimental results was found not exceeding 15%. Research limitations/implications: The accuracy of analytical solutions is verified by the adaptive finite elements method (FEM) with commercial ANSYS 2020 R2 software. Practical implications: Free vibration experiments on 3D-printed FGM plates bonded with two thin solid face sheets at the top and bottom surfaces were conducted. Originality/value: The novel sandwich plate consists of one porous polymer core and two homogenous skins which can be widely applied in various fields of aircraft structures, biomedical engineering, and defense technology. This paper presents an analytical and experimental study to investigate the free vibration problem of a functionally graded simply supported rectangular sandwich plate with porosities. The objective of the current work is to examine the effects of some key parameters, such as porous ratio, power-law index, and slenderness ratio, on the natural frequencies and damping characteristics.

3

Non destructive evaluation based on time stepping finite element electromagnetic fields and mechanical structural deformation coupling models

Abba Faiza, Rachek M’hemed

Przegląd Elektrotechniczny

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2020

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R. 96, nr 7

135--140

EN

The paper deal with high sensitive Non Destructive Testing of ferromagnetic materials based on the maximum mechanical structural deformation versus maximum eddy current electromagnetic force behaviors. Both physical quantities are computed from the transient electromagnetic fields and mechanical structural deformations models solved using the finite element method combined with the Newton–Raphson (N–R) algorithm. The proposed models are applied for an electromagnetic actuator (EMAs) evaluation through the comparison between the maximum deformation-maximum force profiles for healthy and geometrical defect cases under various lift-offs.

PL

W artykule przestawiono czułą metodę defektoskopii materiałów ferromagnetycznych bazującą na związku miedzy deformacją I prądami wirowymi. Do analizy defektów struktury wykorzystano metodę elementów skończonych oraz algorytm Newtona-Raphsona.

4

Behaviour of frictional joints in steel arch yielding supports

Horyl P., Snuparek R., Marsalek P.

Archives of Mining Sciences

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2014

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Vol. 59, no. 3

781--792

EN

The loading capacity and ability of steel arch supports to accept deformations from the surrounding rock mass is influenced significantly by the function of the connections and in particular, the tightening of the bolts. This contribution deals with computer modelling of the yielding bolt connections for different torques to determine the load-bearing capacity of the connections. Another parameter that affects the loading capacity significantly is the value of the friction coefficient of the contacts between the elements of the joints. The authors investigated both the behaviour and conditions of the individual parts for three values of tightening moment and the relation between the value of screw tightening and load-bearing capacity of the connections for different friction coefficients. ANSYS software and the finite element method were used for the computer modelling. The solution is nonlinear because of the bi-linear material properties of steel and the large deformations. The geometry of the computer model was created from designs of all four parts of the structure. The calculation also defines the weakest part of the joint’s structure based on stress analysis. The load was divided into two loading steps: the pre-tensioning of connecting bolts and the deformation loading corresponding to 50-mm slip of one support. The full Newton-Raphson method was chosen for the solution. The calculations were carried out on a computer at the Supercomputing Centre VSB-Technical University of Ostrava.

PL

Nośność stalowych podpór łukowych i ich zdolność do przenoszenia odkształceń spowodowanych przez sąsiadujące warstwy skalne w dużej mierze uwarunkowana jest przez działanie połączeń, w szczególności przez siłę dokręcenia śrub. Praca niniejsza zajmuje się modelowaniem komputerowym podatnych połączeń śrubowych dla różnych momentów skręcających w celu określenia wielkości obciążeń przenoszonych przez połączenia. Innym parametrem w znacznym stopniu warunkującym nośność jest wartość współczynnika tarcia na połączeniach pomiędzy komponentami złączy. Autorzy zbadali zachowanie i warunki pracy poszczególnych elementów dla trzech wartości momentu dokręcającego, a także zbadali związek pomiędzy stopniem dokręcenia śruby a nośnością całego połączenia dla różnych wartości współczynnika tarcia. W modelowaniu komputerowym wykorzystano oprogramowanie ANSYS oraz metodę elementów skończonych. Rozwiązanie problemu jest nieliniowe ze względu na bi-liniowe właściwości materiałowe stali i z uwagi na wielkość odkształceń. Geometrię modelu komputerowego stworzono na podstawie projektów wszystkich czterech elementów konstrukcji. Obliczenia pozwalają także na zidentyfikowanie najsłabszego elementu w połączeniu w oparciu o analizę wytrzymałościową. Obciążenie przykładane podzielono na dwa etapy: wstępne naprężenie śrub i obciążenie odkształcające odpowiadające 50-mm przesunięciu jednej z podpór. W rozwiązaniu wykorzystano pełną metodę Newtona-Raphsona. Obliczenia przeprowadzono na komputerze w centrum obliczeniowym Supercomputing Centre na Uniwersytecie Technicznym w Ostravie.

5

Hybrid computational systems instructural mechanics

Waszczyszyn Z., Pabisek E., Kaliszuk J.

Czasopismo Techniczne. Mechanika

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2010

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R. 107, z. 4-M

135-146

EN

The first problem discussed in the paper is related to the reliability of structures. The simulation of the ultimate load of a steel girder is analized by means of a hybrid computational system FEM & ANN & p-EMP. The system consists of three components, with a low fusion grade. FEM is applied for 'off line' computing of the patterns for ANN training and testing. The trained ANN is then used for very fast generation of MC trials for the hybrid Monte Carlo method (HMC). The second problem corresponds to the identification of a neural material model (NMM) in elasto-plastic plane stress problems. The autoprogressive method (APM) was applied in a formulated hybrid system FEM/NMM/p-EMP with a very high fusion grade of components. The 'on line' interaction of all the components is applied at each load incremental step. In the third part of the paper the standing seminar on the application of ANN s in civil engineering, inspired by the ideas of the famous Professor Życzkowski's Seminar on applied mechanics, is briefly described.

PL

Pierwszy problem, analizowany w tym artykule, dotyczy analizy niezawodności konstrukcji. Nośność graniczna dźwigara stalowego jest symulowana za pomocą hybrydowego systemu obliczeniowego FEM & p-EMP. FEM jest stosowana do obliczania wzorców uczących i testujących ANN. Nauczona sieć służy do szybkiego generowania pseudolosowych próbek w symulacjach hybrydowej metody Monte Carlo (HMC). Drugi problem odnosi się do identyfikacji neuronowego modelu materiału ekwiwalentnego (NMM) w wybranych problemach płaskiego stanu naprężeń. Zastosowano system hybrydowy FEM/NMM/p-EMP charakteryzujący się bardzo wysokim stopniem integracji użytych komponentów. Do identyfikacji NMM zastosowano metodę autoprogresywną (AMP), która opiera się na interakcji 'on line' wszystkich komponentów na każdym przyroście obciążenia. Trzecia część pracy jest poświecona stałemu seminarium nt. stosowania ANNs w inżynierii lądowej, inspirowanego przez słynne Seminarium Profesora Życzkowskiego z zakresu mechaniki stosowanej.

6

Analysis of three-dimensional binary alloy solidification with shrinkage cavity formation

Skrzypczak T., Węgrzyn-Skrzypczak E.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 4

199--204

EN

The paper focuses on modeling of binary alloy solidification process with using Finite Element Method (FEM). The process is characterized by liquidus and solidus temperatures which are constant because solutal segregation is neglected. Analysed region is threedimensional and consists of casting and riser. Mathematical and numerical models of solidification process are presented in the paper. The main focus is put on the algorithm of shrinkage cavity creation process. On the base of mathematical and numerical model computer program has been made. It is capable to simulate shrinkage cavity formation. Two examples show the results of different calculations performed by the program. The first example shows shrinkage cavity created during fast cooling of the top part of the riser while the second one was performed by significantly slower cooling. The shape and localization of shrinkage cavity obtained from simulation is compared to defect which was created during experiment.

7

Design of basic chamber of the Main Control Valve

Lee S., Shin Y., Byun C.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 28, nr 2

175-178

EN

Purpose: The development of a control valve for closed circuit requires comprehensive technologies in the overall precision machinery industry, from the development of casting materials for the housing to various types of parts. The development of a new type of control valve would have great advantage with a long lifecycle. Therefore, it is necessary to secure the MCV (Main Control Valve) development technology that applies various sensors. This paper aims at providing a fundamental base for the establishment of design systems including the flow chamber design database of the MCV for wheel loaders, strength and rigidity design system, and the system for energy efficiency improvement. Particularly, this study set up the basic design database for the flow chamber design to establish the flow chamber design database, and secured the stability of the flow chamber from the basic design stage. In addition, major design variables were determined by utilizing a statistical technique in order to design such flow chamber. Design/methodology/approach: This study uses the I-DEAS to analyze the MCV structure characteristics. In addition, it uses the factorial design and sensitivity analysis to select important factors for the MCV design. Findings: This study establishes the unit flow chamber database for the MCV housing unit and the governing equation for the flow chamber. Research limitations/implications: Since the MCV damage often occurs due to the problem with the material itself and in the manufacturing process, it is difficult to tell clearly whether it occurred as the MCV reached the failure pressure. Practical implications: The basic data needed to design the MCV can be provided, and the required time for the design and the reliability of the design can be reduced and improved respectively. Originality/value: The verification of the design factors obtained from the flow analysis and structural analysis as well as the DOE was made by fabricating a sample MCV and performing tests on it.