1. Fatigue of triply periodic minimal surface (TPMS) metamaterials – a reviewŽiga Žnidarič, Branko Nečemer, Matej Vesenjak, Srečko Glodež, 2025, review article Abstract: A review of the fatigue behavior of triply periodic minimal surface (TPMS) metamaterials with consideration for their fabrication is presented in this paper. The review analyses the most common TPMS geometries used due to their mechanical characteristics. Production methods and the base materials used are presented with the key advantages and drawbacks. Furthermore, the mechanical characteristics of cellular structures with emphasis on TPMS geometries are described. Lastly, the state-of-the-art findings of their fatigue behavior are analyzed and explained. Based on the findings in this article, cellular geometries based on TPMS are superior to conventional cellular structures when comparing their fatigue life. Because of the smooth transitions between struts or surfaces, the stress distribution is much more uniform without stress concentration zones.
Keywords: cellular structures, TPMS metamaterials, production technologies, mechanical characterization, fatigue behavior
Published in DKUM: 09.12.2025; Views: 0; Downloads: 2
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2. Termo-mehanska analiza nosilca za valjeŽan Gorenšek, 2025, master's thesis Abstract: V magistrskem delu analiziramo nosilec za valje, ki je skupaj z valji izpostavljen ciklični toplotni obdelavi. Pri tej temperature močno narastejo, kar povzroča pojav lezenja. Mehanizem lezenja, njegovi vplivi ter uporabljene metode analize so sistematično predstavljeni. Na tej podlagi pripravimo numerični model in izvedemo preračune ključnih parametrov prestopa toplote. Sledi termo-mehanska numerična simulacija obravnavane toplotne obdelave. Na podlagi dobljenih rezultatov ocenimo življenjsko dobo nosilca oziroma določimo število ciklov toplotnih obdelav do porušitve.
Keywords: lezenje, dimenzioniranje na življenjsko dobo, numerična simulacija, toplotne obdelave, prestop toplote
Published in DKUM: 09.12.2025; Views: 0; Downloads: 0
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3. Fatigue and fracture characterisation of copper-brazed 316L stainless steelTonica Bončina, Franc Zupanič, Branko Nečemer, Roman Satošek, Erik Rihter, Srečko Glodež, 2026, original scientific article Abstract: This study focuses on the mechanical, fatigue and metallographic characterisation of copper-brazed 316L stainless steel for the potential use in different plate heat exchangers (PHE) applications. The quasi-static and fatigue tests have been performed on the specially designed copper-brazed tensile specimens to obtain the engineering stress–strain diagram and the fatigue life curve of the analysed brazed joint. Furthermore, a comprehensive metallographic investigation has been done, focusing on (i) material characterisation of asreceived stainless steel 316L, (ii) characterisation of the brazed joint and (iii) fractographic analyses of fractured surfaces by quasi-static and fatigue loading. The obtained experimental results may be beneficial for designing copper-brazed plate heat exchangers in the future.
Keywords: brazed joint, fatigue, experimental testing, metallographic investigation
Published in DKUM: 28.11.2025; Views: 0; Downloads: 2
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4. Parametrično modeliranje podpor iz nerjavnih in konstrukcijskih jekel za podpiranje cevnih sistemovBlaž Ojsteršek, 2025, undergraduate thesis Abstract: Delo obravnava razvoj parametričnih 3D-modelov cevnih podpor, ki pokrivajo najpogostejše izvedbe (stenske, talne in stropne). Komponente so zasnovane v PTC Creo z uporabo relacij in logike (npr. IF–ELSE), zato se ključne mere in standardni elementi, kot je U-objemka, samodejno prilagodijo izbranemu premeru cevi ter montažnim zahtevam. Metodologija združuje osnovne analitične preračune z statičnimi numeričnimi simulacijami, s katerimi se preverita togost in varnost podpore pri tipičnih obremenitvah. Za prikaz materialnega vpliva sta primerjana S235JR in AISI 304; prvi je praviloma ekonomsko ugodnejši za manj zahtevna okolja, drugi pa primernejši za korozijsko izpostavljene aplikacije. Izvedena je tudi kontrola numeričnih simulacij, kar poveča zanesljivost rezultatov. Predlagan pristop omogoča hitrejše projektiranje, lažje standardiziranje kosovnic in risb ter ponovljivo pripravo tehnične dokumentacije, s čimer se skrajšata čas in strošek razvoja ter izboljša sledljivost pri spremembah.
Keywords: parametrično modeliranje, cevne podpore, PTC Creo, U-objemka, stenska/talna/stropna podpora, S235JR, AISI 304, numerična simulacija
Published in DKUM: 02.10.2025; Views: 0; Downloads: 7
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5. Uporaba generativnega oblikovanja za optimizacijo okvirja kolesaVid Lunežnik, 2025, undergraduate thesis Abstract: V zaključnem delu je obravnavana uporaba generativnega oblikovanja pri optimizaciji okvirja cestnega kolesa. Prvo je bil izdelan referenčni model okvirja kolesa kateri predstavlja zasnovo klasičnega sodobnega okvirja cestnega kolesa in nam je služil za primerjavo z generativno oblikovanim okvirjem. Nato je bil s procesom generativnega oblikovanja v programu Autodesk Fusion ustvarjen optimiziran okvir. Na osnovi treh obremenitvenih primerov so bile izvedene trdnostne analize z namenom vrednotenja napetostih in deformacij obeh okvirjev, na podlagi katerih je bila nato izvedena primerjava izvedb okvirjev.
Keywords: generativno oblikovanje, okvir kolesa, Fusion, optimizacija, 3D modeliranje
Published in DKUM: 01.10.2025; Views: 0; Downloads: 9
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6. Izboljšanje mehanskih lastnosti 3d tiskane polilaktične kisline (pla) s postopkom žarjenja za uporabo pri izdelavi protetičnih ležišč : magistrsko deloMatjaž Mir, 2025, master's thesis Abstract: Magistrsko delo raziskuje vpliv toplotne obdelave na mehanske in geometrijske spremembe 3D tiskanih izdelkov iz PLA. Cilj raziskave je preveriti možnost izboljšanja mehanskih lastnosti za uporabo pri izdelavi protetičnih ležišč. Uporabljene so metode 3D tiska, toplotne obdelave, DMA analiza in izvajanje nateznih preizkusov. Prav tako je bil analiziran vpliv toplotne obdelave na geometrijske spremembe protetičnega ležišča. Rezultati so pokazali, da natezne trdnosti žarjenje ne izboljša. Žarjenje je povečalo modul elastičnosti in povzročilo velike spremembe geometrije.
Keywords: PLA, žarjenje, protetično ležišče, mehanske lastnosti, 3D tisk
Published in DKUM: 27.08.2025; Views: 0; Downloads: 27
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7. Fatigue behaviour of different chiral auxetic structures using a numerical approachBranko Nečemer, Patrik Lampret, Srečko Glodež, 2025, original scientific article Abstract: This study presents the computational analysis for determining the fatigue life of different chiral auxetic structures made of aluminium alloys 5083-H111. The influence of Poisson's ratio on the loading process was investigated to determine which structures exhibited the auxetic effect and how intense it was. Finally, the fatigue life calculation was performed using the strain life approach in the framework of the ANSYS software. The fatigue life determination was evaluated using the approach of amplitude strains, amplitude forces, and strain energy density per cycle. The computational results were described and presented according to predefined approaches, from which it was determined which chiral structure can withstand the highest number of loading cycles at the prescribed load, and which structure shows the most favourable combination of mechanical and physical properties.
Keywords: advanced metamaterials, chiral auxetic structures, fatigue behaviour, numerical simulations, aluminium alloys
Published in DKUM: 20.05.2025; Views: 0; Downloads: 12
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8. Geometrijske in mehanske lastnosti celičnih metamaterialovNejc Novak, Branko Nečemer, 2025, reviewed university, higher education or higher vocational education textbook Abstract: Učbenik z naslovom "Mehanske in geometrijske lastnosti celičnih metamaterialov" je namenjen kot študijsko gradivo pri predavanjih predmetov Konstruiranje s celičnimi gradivi in Dimenzioniranje lahkih konstrukcij za študente Univerze v Mariboru. Učbenik temelji na raziskavah naprednih metamaterialov, ki združujejo edinstvene mehanske in geometrijske lastnosti. Vsebuje pregled sodobnih celičnih metamaterialov in izdelovalnih tehnologij, uporaba eksperimentalnih in numeričnih pristopov, ter izsledke opravljenih raziskav mehanske in geometrijske karakterizacije. Vsebina učbenika je v skladu z učnimi načrti omenjenih predmetov.
Keywords: celični metamateriali, mehanske lastnosti, geometrijske lastnosti, mehansko testiranje, računalniške simulacije
Published in DKUM: 13.05.2025; Views: 0; Downloads: 104
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9. Fatigue behaviour of copper-brazed 316L stainless steelJernej Kralj, Blaž Hanželič, Srečko Glodež, Janez Kramberger, Roman Satošek, Branko Nečemer, 2024, original scientific article Abstract: The plate heat exchanger (PHE) is a component that provides heat to be transferred from hot water to domestic cold water with-out mixing them with high efficiency. Over the lifetime of the PHE, cyclic pressure acts on the brazing points and the plates, andthis can lead to fatigue failure. The fatigue behaviour of the PHE, designed by using copper-brazed 316L (also known as 1.4404) stainless steel, was investigated by performing fatigue tests to obtain the S-N curve of the analysed brazed joint. The fatigue tests were performed on a Vibrophore 100 testing machine under the load ratio R= 0.1 for different values of calculated ampli-tude stress. Based on the obtained experimental results, an appropriate material model of the analysed brazed joint was created, which was validated with a numerical calculation in the framework of a program code Ansys. A validated material model canthen be used for the subsequent numerical analysis of the PHE.
Keywords: plate heat exchanger, brazed joint, fatigue, experimental testing
Published in DKUM: 10.04.2025; Views: 0; Downloads: 24
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10. Fatigue behaviour of PA66 GF30 at different temperaturesMarko Zadravec, Janez Kramberger, Branko Nečemer, Srečko Glodež, 2024, original scientific article Abstract: 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.
Keywords: PA66 GF30, increased temperatures, fatigue, experimental testing
Published in DKUM: 10.03.2025; Views: 0; Downloads: 11
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