1. Fatigue behaviour of PA66 GF30 at different temperaturesMarko Zadravec, Janez Kramberger, Branko Nečemer, Srečko Glodež, 2024, izvirni znanstveni članek Opis: A comprehensive experimental investigation to understand the mechanical properties and fatigue behaviour of glass-reinforced polyamide (PA66 GF30) at different temperatures is presented in this paper. The specimens for quasi-static and fatigue testing were machined from previously extruded plates, where two orientations were considered: (i) the extrusion direction (ED) and (ii) the direction perpendicular to extrusion (PED). Both the quasi-static and fatigue tests were performed under different temperatures (22 ◦C and 100 ◦C). The fatigue tests were performed in a load control regime under pulsating loading (R = 0.1) to create S–N curves for all the temperatures and loading directions. The experimental results of the quasi-static tests showed that the test specimens manufactured in the extrusion direction have better mechanical properties when compared to those of the specimens manufactured perpendicular to the extrusion direction. Furthermore, the analysis of the quasi-static tensile test results showed that tensile strength, yield strength, and the modulus of elasticity are significantly dependent on the temperature and deteriorate when the temperature is increased from 22 ◦C to 100 ◦C. The results of the fatigue tests showed that at both the temperatures (22 ◦C and 100 ◦C), the samples produced in the direction of extrusion exhibited higher fatigue strength than those produced perpendicular to the direction of extrusion. For all the sample orientations, the fatigue strength decreased significantly with increasing temperature. The obtained experimental results could be very useful when designing and dimensioning different dynamically loaded engineering components made of PA66 GF30 subjected to high temperatures.
Ključne besede: PA66 GF30, increased temperatures, fatigue, experimental testing
Objavljeno v DKUM: 10.03.2025; Ogledov: 0; Prenosov: 2
 Celotno besedilo (1,93 MB)
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2. Vibration fatigue analysis of two different variants of oil suction pipesMarko Zadravec, Srečko Glodež, Christian Buzzi, Peter Brunnhofer, Martin Leitner, Janez Kramberger, 2024, izvirni znanstveni članek Opis: In order to reduce the overall mass of the product, an improved variant of the engine oil suction pipe in hybrid design is developed and analysed as part of this paper. The vibration fatigue analysis of a simple all-metal suction pipe and the new hybrid suction pipe variant is derived using computer FEA simulations and vibration measurements on the shaker. The hybrid design of the technical components makes it possible to combine different types of materials in order to achieve the best possible properties and behaviours for the components under the influence of external loads. In our case, we combine a suction pipe made of S235JR mild steel with a 3D-printed polyamide intake funnel featuring a grid designed to prevent particles from entering the engine’s lubrication circuit. This design reduces the mass and shifts the centre of gravity closer to the attachment point of the pipe, as well as to the engine crankcase, which has a positive effect on the values of natural frequencies and vibration amplitudes. The main objective of such a hybrid suction pipe is precisely to reduce vibrations, and thus extend the service life of the components.
Ključne besede: oil suction pipe, vibration fatigue, failure analyses, experimental testing, numerical simulations
Objavljeno v DKUM: 26.02.2024; Ogledov: 641; Prenosov: 641
Celotno besedilo (6,90 MB)
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3. Analiza vibracijskega utrujanja sesalne cevi črpalke olja v motorju z notranjim zgorevanjem : magistrsko deloMarko Zadravec, 2021, magistrsko delo Opis: S pomočjo numeričnih simulacij po metodi končnih elementov, izračuna lastnih vrednosti, vzbujanja in izračuna varnostnih faktorjev, nam je v okviru magistrskega dela uspelo medsebojno primerjati in oceniti dve varianti sesalne cevi za olje motorja TCD 3.6 L4. Vrednotenje konceptnih variant je potekalo na podlagi realnih obremenitev, pridobljenih z meritvami med delovanjem motorja. Ugotovili smo, da je nova konceptna varianta ustrezna, saj je bistveno bolj toga kot obstoječa varianta sesalne cevi za olje.
Ključne besede: sesalna cev črpalke olja, vrednotenje variant, MKE
Objavljeno v DKUM: 28.09.2021; Ogledov: 824; Prenosov: 5
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4. Numerična analiza nosilca kompresorja klime : diplomsko deloMarko Zadravec, 2019, diplomsko delo Opis: V okviru diplomskega dela smo s pomočjo statičnih analiz nosilca kompresorja klime, izvedenih v programskem paketu ABAQUS CAE 2018, rešili problem, povezan s prevelikimi pomiki nosilca in kompresorja. Na podlagi rezultatov računalniških simulacij posameznih variant smo s postopnim dodajanjem reber in pritrditvijo dodatnega podpornega nosilca direktno na blok motorja TCD 2.2 L3 dosegli kar 40,8 % zmanjšanje pomika nosilca, iz začetnih 0,1463 mm na končnih 0,0866 mm.
Ključne besede: Nosilec kompresorja klime, MKE, Statične analize
Objavljeno v DKUM: 13.09.2019; Ogledov: 1404; Prenosov: 37
Celotno besedilo (3,54 MB) |
5. Vodenje linearnega pogona s Siemens PLKMarko Zadravec, 2017, diplomsko delo Opis: Povzetek
Linearni pogoni so v montažni industriji zelo pomemben člen avtomatizacije procesov. Uporabljamo jih za prestavljanje elementov, ki so sestavni deli izdelka, premikanje orodij ipd. V diplomskem delu je bil izdelan demonstracijski sistem z linearnim pogonom, s katerim je možno izvajati vaje, raziskave ter različne projektne naloge. Omenjeni sistem je sestavljen iz linearnega pogona z jermenskim prenosom, gnanim s servomotorjem. Ta servomotor krmili namenski krmilnik, ki je preko vhodov in izhodov ter komunikacijskega protokola PROFIBUS povezan na programirljivi logični krmilnik (PLK). Krmilniška konfiguracija je sestavljena iz Siemensove serije krmilnikov S7-1500, linearni pogon in vso pripadajočo strojno opremo pa proizvaja FESTO.
Ključne besede: PLK, linearni pogon, servo motor, vodenje, PROFIBUS
Objavljeno v DKUM: 24.10.2017; Ogledov: 1876; Prenosov: 247
Celotno besedilo (7,52 MB) |
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