Numeričko modeliranje dinamičkih procesa deformiranja tankih bakrenih limova

master's thesis

• Title (english): Numerical modeling of dynamic deformation processes of thin copper sheets
• Author: Denis Pevec
• Mentor: Zdenko Tonković (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2016-07-15, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Krimpanje je jedan od osnovnih postupaka spajanja žica i konektora koji se vrlo često koristi zbog svoje jednostavnosti, pouzdanosti i niskih troškova. Ostvaruje se deformiranjem konektora u kojem se pojavljuju plastične deformacije koje omogućuju čvrsti spoj između žica i konektora. Cilj je ostvariti kvalitetan kontakt između konektora i žica uz odgovarajuću vlačnu čvrstoću. Računanje potrebne plastične deformacije konektora kod koje se ostvaruje kvalitetan spoj najčešće se provodi metodom konačnih elemenata. Točnost numeričkog proračuna ovisi o ispravnom postavljanju numeričkog modela, a provjerava se validacijom, odnosno verifikacijom. Kako je eksperimentalno modeliranje procesa krimpanja žica i mjerenje fizikalnih veličina vrlo složeno, validacija numeričkog modela provedena je dinamičkim deformiranjem šest bakrenih limova postavljenih jedan na drugi. Tijekom deformiranja bakrenih limova provedeno je mjerenje raspodjele pomaka i temperature modela. Rezultati dobiveni numeričkom analizom u računalnom paketu Abaqus su uspoređeni s eksperimentalnim mjerenjima. Kako bi se smanjilo računalno vrijeme, geometrija uzoraka diskretizirala se s 2D konačnim elementima te su rezultati uspoređeni s 3D numeričkim modelom. Rad se sastoji od šest poglavlja. U prvom poglavlju dan je kratki uvod i osvrt na proces krimpanja. U drugom poglavlju prikazane su teorijske osnove procesa dinamičkog deformiranja s osnovnim jednadžbama prijenosa topline i čvrstoće materijala koji čine matematički model dinamičkog procesa deformiranja, dok su u trećem poglavlju dani temelji numeričkog modela metodom konačnih elemenata. U četvrtom poglavlju opisan je eksperimentalni model dinamičkog procesa deformiranja bakrenih limova i prikazani su rezultati eksperimenta. U petom poglavlju opisan je numerički model dinamičkog procesa deformiranja bakrenih limova s 3D konačnim elementima te je dana usporedba rezultata s eksperimentalnim mjerenjima. Također, prikazan je pojednostavljeni numerički model diskretiziran s 2D elementima. U šestom poglavlju dan je zaključak rada. Zaključeno je da se zbog horizontalnog pomaka čeličnog prizmatičnog bloka rezultati dobiveni u Abaqusu malo razlikuju od eksperimentalnih rezultata. Također, zaključeno je da 2D numerički model dobro opisuje dinamičko deformiranje bakrenih limova te se mogu koristiti za parametarska istraživanja.

Abstract (english)

Crimping is one of the basic wire and connector connecting procedures that is commonly used because of its simplicity, reliability and low cost. It is achieved by deforming the connector in which the plastic deformation appears which enables rigid connection between the wires and connector. The aim is to achieve quality contact between the connector and the wires with appropriate tensile strength. Calculation of the required plastic deformation of connectors at which they achieve a good bond is usually carried out by finite element method. The accuracy of numerical calculation depends on the correct numerical modelling and it is checked by the validation or verification. As the experimental modelling of the crimping wire process and measurement of the physical quantities is very complex, validation of numerical model is carried out by the dynamic deformation of six copper plates on top of each other. During the deformation of the copper plates, the displacement and temperature distribution was measured. The results obtained by numerical analysis in the computer package Abaqus were compared with experimental measurements. In order to reduce the computing time, the geometry of samples was discretized with 2D finite elements and the results were compared with the 3D numerical model. The thesis is divided in six chapters. The first chapter is a brief introduction and overview of the crimping process. In the second chapter, the theoretical foundations of the process of dynamic deformation with the basic equations of heat transfer and strength of materials that makes the mathematical model of the dynamic processes of deformation are shown. Third chapter shows the foundations of numerical modelling using finite element method. The fourth chapter describes the experimental model of dynamic deformation processes of copper sheets and shows the experimental results. The fifth chapter describes the numerical modelling of dynamic deformation processes of copper sheets with 3D finite elements, and gives the result comparison with experimental measurements. Also, a simplified numerical model discretized with 2D elements is shown. The sixth chapter is the conclusion of the thesis. Conclusion follows that due to the horizontal displacement of steel prismatic block results obtained in Abaqus are a bit different from the experimental results. Also, it is concluded that the 2D numerical model describes the dynamic deformation of the copper plates well and can be used for parametric studies.

• Keywords: krimpanje; metoda konačnih elemenata; dinamičko deformiranje; bakreni limovi
• Keywords (english): crimping; finite element analysis; dynamic deformation; copper sheets
• Language: croatian
• URN:NBN: urn:nbn:hr:235:055584
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-22 17:06:19